AN645: Si477x Programming Guide

AN645
S i477 X P ROGRAMMING G UIDE
1. Introduction
This document provides an overview of the programming requirements for the Si477x AM/FM receiver with support
for an external IBOC HD demodulator. The hardware control interface and software commands are detailed along
with several examples of the required steps to configure the device for various modes of operation. Table 1
provides a programming guide cross-reference for each Si477x part released by Silicon Labs to date. This
programming guide focuses on the Si477x-A20 release.
Table 1. Si477x Programming Guide and Firmware Revisions
Part #
Si477x-A20
Part Revision
FMRX
Component
AMRX
Component
Programming
Guide Revision
2.0
10.1.0
9.1.0
0.2
2. Overview
This family of products is programmed using commands and responses. To perform an action, the system
controller writes a command byte and associated arguments, which cause the device to execute the given
command. The device will, in turn, provide a response depending on the type of command that was sent.
The device has a slave control interface that allows the system controller to send commands to and receive
responses from the device using 2-wire mode (I2C compatible).
3. Terminology
to send
Complete
NVM—Non-volatile internal device memory
Device—Refers to the AM/FM Receiver
System Controller—Refers to the system microcontroller
CMD—Command byte
ARGn—Argument byte (n = 1 to 7)
STATUS—Status byte
RESPn—Response byte (n = 1 to 15)
CTS—Clear
STC—Seek/Tune
Rev. 0.3 8/13
Copyright © 2012 by Silicon Laboratories
AN645
AN645
4. Control Interface
The Si477x provides an I2C-compatible, 2-wire control interface.
In powerdown mode, all circuitry is disabled except for the device control interface. The device comes out of
powerdown mode when the POWER_UP command is written to the command register. Once in powerup mode,
the device accepts additional commands such as tuning. The device will not accept commands while in
powerdown mode, with the exception of the powerup command. If the system controller writes a command other
than POWER_UP when in powerdown mode, the device does not respond, and the command is ignored.
Setting the RSTB pin low places the device in reset mode. In reset mode, all circuitry is disabled including the
device control interface; registers are set to their default settings, and the control bus is disabled.
4.1. 2-Wire Control Interface
Figure 1 and Figure 2 show the 2-wire control interface read and write timing parameters and diagrams,
respectively. Refer to the Si477x data sheet for timing parameter values.
SCL
SDA
tSU:STA tHD:STA
tLOW
START
tr:IN
tHIGH
tr:IN
tf:IN
tSP
tSU:STO
tBUF
70%
30%
70%
30%
tHD:DAT tSU:DAT
tf:IN,
tf:OUT
tPD:DAT
STOP
START
Figure 1. I2C Control Interface Read and Write Timing Parameters
SCL
SDA
(Write)
Command
7-0
A6-A0, 0
START
SDA
(Read)
ADDRESS + R/W
ACK
ADDRESS + R/W
ACK
Status
7-0
A6-A0, 1
START
DATA
Arg1
7-0
ACK
DATA
DATA
Rev. 0.3
STOP
ACK
STOP
Response
7-0
ACK
DATA
Figure 2. I2C Control Interface Read and Write Timing Diagram
2
ACK
AN645
Two-wire bus mode uses the SCL and SDA pins for signaling. A transaction begins with the START condition,
which occurs when SDA falls while SCL is high. Next, the system controller drives an 8-bit control word serially on
SDA, which is captured by the device on rising edges of SCL. The control word consists of a seven-bit device
address followed by a read/write bit (read = 1, write = 0). The device acknowledges the control word by driving
SDA low on the next falling edge of SCL.
For write operations, the system controller next sends a data byte on SDA, which is captured by the device on
rising edges of SCL. The device acknowledges each data byte by driving SDA low for one cycle on the next falling
edge of SCL. For each write transaction, the first byte is a command and the following bytes are arguments.
For read operations, after the device has acknowledged the control byte, it will drive an eight-bit data byte on SDA,
changing the state of SDA on the falling edges of SCL. The system controller acknowledges each data byte by
driving SDA low for one cycle on the next falling edge of SCL. If a data byte is not acknowledged by the system
controller, the transaction will end. For each read transaction, the first byte is the status byte and the following bytes
are the response data from the receiver.
A 2-wire transaction ends with the STOP condition, which occurs when SDA rises while SCL is high.
Rev. 0.3
3
AN645
5. Powerup and Powerdown
There are two procedures for powering up a receiver to move it from powerdown mode to the powerup mode. The
first is a powerup from internal receiver memory. The second is a powerup from a firmware component patch that is
stored in system controller memory. Patches can be applied to a firmware component by the system controller via
a download mechanism to address field issues, errata, or adjust device behavior. Patches are encrypted and
unique to a particular device firmware version, cannot be generated by customers, and can be used to replace a
portion of the component (to address errata, for example) or to download an entirely new component. The user
must verify that the device contains the correct base firmware to support the patch as described later in this
section.
It is possible to configure the receiver for operation with a crystal or an external clock. Refer to Table 2 below.
Table 2. Clocking Options
Frequency
(MHz)
Crystal
External
Clock
37.209375
X
X
36.4
X
X
37.8
X
X
Powerup from device memory is described in section “5.1. Powerup from Internal Memory” using a patch is
described in section “5.2. Powerup from a Patch”.
4
Rev. 0.3
AN645
5.1. Powerup from Internal Memory
START
1. Supply VA, VD, VIO1 and
VIO2 while keeping the RSTB
=0
2. After a minimum of 100uS,
set RSTB = 1
3. After a minimum of 100uS,
continue to the next step
4. Send the POWER_UP
command for the desired
function (AM, FM)
5. Commence normal
operation
6. Send POWER_DOWN
command
1. Supply VA, VD, VIO1 and VIO2 while keeping the RSTB=0. Power supplies may be sequenced in any order.
2. After a minimum of 100 µs, set RSTB=1.
3. After a minimum of 100 µs, continue to the next step.
4. Send the POWER_UP command for the desired function (AM, FM). Example (with crystal 36.4 MHz, FM
function):
Rev. 0.3
5
AN645
POWER_UP Command
Action
Data
Description
CMD
0x01
POWER_UP
ARG1
0xF7
Normal operation.
ARG2
0x28
Crystal load capacitance=11.08pF
ARG3
0x07
Disables CTS interrupt, crystal bias=7.
ARG4
0x12
FM function, crystal frequency 36.4 MHz.
ARG5
0x11
Crystal, receiver 1.
STATUS
→0x80
Example (with external clock 36.4 MHz, FM function):
POWER_UP Command
Action
Data
Description
CMD
0x01
POWER_UP
ARG1
0x77
Normal operation.
ARG2
0x00
Crystal load capacitance=0pF
ARG3
0x03
Disables CTS interrupt, crystal bias = 3.
ARG4
0x12
FM function, crystal frequency 36.4 MHz.
ARG5
0x12
External clock, receiver.
STATUS
→0x80
5. The device is ready to commence normal operation and accept additional commands. Refer to Figure 3.
Figure 3. Powerup Timing
6. If desired, send the POWER_DOWN command.
6
Rev. 0.3
AN645
Example:
POWER_DOWN Command
Action
Data
Description
CMD
0x11
POWER_DOWN
ARG1
0x00
Disable oscillator (ARG1 may be omitted with the same result)
STATUS
→0x80
CTS=1
7. It is now possible to move to the powerup state by returning to step 4.
Rev. 0.3
7
AN645
5.2. Powerup from a Patch
START
A
1. Supply VA, VD, VIO1 and
VIO2 while keeping the RSTB
=0
4. Send the POWER_UP
command for the desired
function (AM, FM)
2. After a minimum of 100uS,
set RSTB = 1
5. Send PART_INFO
command.
3. After a minimum of 100uS,
continue to the next step
6. Send POWER_DOWN
command.
Verify Firmware and ROM
revision?
B
A
B
7. Send the POWER_UP
command with boot loader
function
8. Send patch data.
9. Send the POWER_UP
command for the desired
function (AM, FM)
10. Commence normal
operation.
11. Send POWER_DOWN
command.
8
Rev. 0.3
AN645
1. Supply VA, VD, VI01 and VI02 while keeping the RSTB=0. Power supplies may be sequenced in any order.
2. After a minimum of 100 µs, set RSTB=1.
3. After a minimum of 100 µs, proceed to the next step.
4. (Optional – step 1 of 3 to verify part firmware revision and ROM revision.) Both part firmware revision and
ROM revision must be compatible with a partial patch and ROM revision must be compatible with a full
patch. Send the POWER_UP command for the desired function (AM, FM). Example (with crystal
36.4 MHz, FM function):
POWER_UP Command
Action
Data
Description
CMD
0x01
POWER_UP
ARG1
0x77
Normal operation.
ARG2
0x28
Crystal load capacitance = 11.08 pF.
ARG3
0x07
Disables CTS interrupt, crystal bias=7.
ARG4
0x12
FM function, crystal frequency 36.4 MHz.
ARG5
0x11
Crystal, receiver 1.
STATUS
→0x80
Example (with external clock 36.4 MHz, FM function):
POWER_UP Command
Action
Data
Description
CMD
0x01
POWER_UP
ARG1
0x77
Normal operation.
ARG2
0x00
Crystal load capacitance = 0 pF.
ARG3
0x03
Disables CTS interrupt, crystal bias=3.
ARG4
0x12
FM function, clock frequency 36.4 MHz.
ARG5
0x12
External clock, receiver 1.
STATUS
→0x80
5. (Optional—step 2 of 3 to verify part firmware revision and ROM revision). Verify part firmware revision and
ROM revision. Send the PART_INFO command.
Rev. 0.3
9
AN645
Example:
PART_INFO Command
Action
Data
Description
CMD
0x02
PART_INFO
STATUS
→0x80
CTS=1
RESP1
→0x06
Chip revision, 6
RESP2
→0x43
Part number, Si47+ last two digits, 0x4D=77, or Si4777
RESP3
→0x02
Firmware major revision=1
RESP4
→0x00
Firmware minor revision=0
RESP5
→0x00
Firmware build version=0
RESP6
→0x00
Reserved, values will vary.
RESP7
→0x00
Reserved, values will vary.
RSP8
→0x04
ROM ID
RESP9
→0x00
Reserved, values will vary.
In this example, the part revision is 2.0.0 and the ROM ID is 4. Ensure that partial patches received from Silicon
Labs are intended for use with the part firmware revision and ROM, and that full patches are intended for use with
the ROM ID as shown in Table 3. It is possible to verify the FM and AM component firmware revisions with the
FUNC_INFO command, however, this is not necessary because there is always a unique mapping of component
revision to part revision.
Table 3. Si477x Firmware and ROM Compatibility
Part #
Si477x-A20
Firmware Revision
ROM ID
2.0
5
FM Revision
10.1.0
AM Revision
9.1.0
6. (Optional—step 3 of 3 to verify part firmware revision and ROM revision.) Send the POWER_DOWN
command. This step is required before proceeding with the patching procedure if steps 4 and 5 have been
followed.
Example
POWER_DOWN Command
Action
Data
Description
CMD
0x11
POWER_DOWN
ARG1
0x00
Disable oscillator (ARG1 may be omitted with the same result)
STATUS
→0x80
CTS=1
7. Send the POWER_UP command for boot loader function.
Example (with crystal 36.4 MHz, boot loader function):
10
Rev. 0.3
AN645
POWER_UP Command
Action
Data
Description
CMD
0x01
POWER_UP
ARG1
0x77
Normal operation.
ARG2
0x28
Crystal load capacitance = 11.08 pF.
ARG3
0x07
Disables CTS interrupt, crystal bias=7.
ARG4
0x02
Boot loader function, crystal frequency 36.4 MHz.
ARG5
0x11
Crystal, receiver 1.
STATUS
→0x80
Example (with external clock 36.4 MHz, boot loader function):
POWER_UP Command
Action
Data
Description
CMD
0x01
POWER_UP
ARG1
0x77
Normal operation.
ARG2
0x00
Crystal load capacitance = 0 pF.
ARG3
0x03
Disables CTS interrupt, crystal bias=3.
ARG4
0x02
Boot loader function, clock frequency 36.4 MHz.
ARG5
0x12
External clock, receiver 1.
STATUS
→0x80
8. Send the patch data.
The patch file provided by Silicon Labs typically has a .csg extension. The system controller must send each line of
8 bytes, wait for a CTS, then send the next line of 8 bytes, etc., until the entire patch has been sent. An example
showing the first few lines and final line of a patch file is shown below. Note that the “#” character indicates a
comment and the patch file indicates the required ROM ID for a partial or full download. If the checksum fails, the
part issues an error code, ERR (bit 6 of the STATUS byte received after each 8-byte transfer), and halts. The part
must be reset to recover from this error condition.
The following is an example of a patch file:
# COPYRIGHT=2011 Silicon Laboratories, Inc.
# GENERATED=13:53 May 23 2011
# ROMID=0x04
# PATCHID=0x228C
# REQUIRES=NONE
# SIZE=8272
# FUNCTION=FMRX
# MAJOR=8
# MINOR=0
# BUILD=8
Rev. 0.3
11
AN645
# CRCT=0x81CF
# CRCM=0x0A6C
# CRCP=0xEC8D
# CRCX=0x66EE
# CRCY=0x6381
# CRCZ=0xA805
0x04,0x11,0x81,0xCF,0x00,0x00,0x0D,0xC6
0x05,0xAE,0xE1,0xBD,0xB4,0x90,0x07,0x33
0x06,0xD9,0x3D,0x11,0xF7,0x25,0xCB,0x06
0x17,0x7A,0xF8,0xD0,0x71,0x10,0x3F,0xB7
0x1F,0xBF,0xFF,0x7E,0x42,0xE7,0x53,0x05
…
[Additional Lines]
…
0x08,0x21,0xAB,0xB5,0xF1,0x7A,0xD6,0x5A
0x08,0x10,0x0E,0x9E,0x3B,0xD1,0x01,0xF4
0x08,0xBF,0x8D,0x94,0xB0,0x2D,0xCF,0xFF
0x05,0x8D,0xB1,0x22,0xF2,0x8D,0x22,0x8C
# END
12
Rev. 0.3
AN645
Example:
First line of the patch file example
Action
Data
CMD
0x04
ARG1
0x11
ARG2
0x81
ARG3
0xCF
ARG4
0x00
ARG5
0x00
ARG6
0x0D
ARG7
0xC6
STATUS
→0x80
Description
Second line of the patch file example
CMD
0x05
ARG1
0xAE
ARG2
0xE1
ARG3
0xBD
ARG4
0xB4
ARG5
0x90
ARG6
0x07
ARG7
0x33
STATUS
→0x80
9. Send the POWER_UP command for the desired function (AM, FM).
Example (with crystal 36.4 MHz, FM function):
POWER_UP Command
Action
Data
Description
CMD
0x01
POWER_UP
ARG1
0x77
Normal operation.
ARG2
0x28
Crystal load capacitance = 11.08 pF.
ARG3
0x07
Disables CTS interrupt, crystal bias=3.
ARG4
0x12
FM function, crystal frequency 36.4 Hz.
ARG5
0x11
Crystal, receiver 1.
STATUS
→0x80
Example (with external clock 36.4 MHz, FM function):
Rev. 0.3
13
AN645
POWER_UP Command
Action
Data
Description
CMD
0x01
POWER_UP
ARG1
0x77
Normal operation.
ARG2
0x00
Crystal load capacitance = 0 pF.
ARG3
0x03
Disables CTS interrupt, crystal bias=3.
ARG4
0x12
FM function, crystal frequency 36.4 MHz.
ARG5
0x12
External clock, receiver 1.
STATUS
→0x80
10. The device is ready to commence normal operation and accept additional commands.
11. If desired, send the POWER_DOWN command.
Example:
POWER_DOWN Command
Action
Data
Description
CMD
0x11
POWER_DOWN
ARG1
0x00
Disable oscillator (ARG1 may be omitted with the same result)
STATUS
→0x80
CTS=1
12. It is now possible to move to the powerup state by returning to step 7.
14
Rev. 0.3
AN645
6. Digital Audio Interface
The digital audio interface operates in slave mode and supports 5 different audio data formats:
2
I S
Audio
Left-Justified
Audio
Right-Justified Audio
DSP Audio
DSP Left-Justified Audio
In I2S mode, the MSB is captured on the second rising edge of DCLK following each DFS transition. The remaining
bits of the word are sent in order down to the LSB. The Left Channel is transferred first when the DFS is low, and
the Right Channel is transferred when the DFS is high.
In left-justified mode, the MSB is captured on the first rising edge of DCLK following each DFS transition. The
remaining bits of the word are sent in order down to the LSB. The Left Channel is transferred first when the DFS is
high, and the Right Channel is transferred when the DFS is low.
In right-justified format, by default, the LSB is captured on the last rising edge of DCLK in each valid DFS interval.
The left channel is transferred first when the DFS is high, and the right channel is transferred when the DFS is low.
In DSP format, the DFS becomes a pulse with a width of one DCLK period. The left channel is transferred first,
followed right away by the right channel. There are two options in transferring the digital audio data in DSP format;
the MSB of the left channel can be transferred on the first rising edge of DCLK following the DFS pulse (leftjustified DSP format) or on the second rising edge.
In all audio formats, depending on the word size, DCLK frequency, and sample rates, there may be unused DCLK
cycles after the LSB of each word before the next DFS transition and MSB of the next word. In addition, the user
can configure the MSB to be captured on the falling edge of DCLK via properties. The number of audio bits can be
configured for 8, 16, 20, or 24 bits.
Rev. 0.3
15
AN645
DCLK
DFS
LEFT CHANNEL
I2S
RIGHT CHANNEL
1 DCLK
DOUT
1
1 DCLK
2
n-2
3
n-1
MSB
n
1
LSB
MSB
2
n-2
3
n-1
n
LSB
Figure 4. I2S Audio Format
DCLK
DFS
DOUT
LEFT CHANNEL
1
2
3
n-2
RIGHT CHANNEL
n-1
MSB
n
1
LSB
MSB
2
n-2
3
n-1
n
LSB
Figure 5. Left-Justified Audio Format
DCLK
DFS
DOUT
LEFT CHANNEL
1
MSB
2
3
RIGHT CHANNEL
n-2
n-1
n
1
LSB
MSB
Figure 6. Right-Justified Audio Format
16
Rev. 0.3
2
3
n-2
n-1
n
LSB
AN645
DCLK
DFS
LEFT CHANNEL
1 DCLK
DOUT
(MSB at 2nd rising edge)
1
2
3
n-2
RIGHT CHANNEL
n-1
MSB
n
1
LSB
MSB
2
3
n-2
n-1
n
LSB
Figure 7. DSP Audio Format
DCLK
DFS
RIGHT CHANNEL
LEFT CHANNEL
DOUT
(MSB at 1st rising edge)
1
MSB
2
3
n-2
n-1
n
1
LSB
MSB
2
3
n-2
n-1
n
LSB
Figure 8. DSP Left-Justified Audio Format
Rev. 0.3
17
AN645
7. Digital ZIF I/Q Interface
The digital ZIF I/Q output can provide the down converted channelized AM/FM signal at baseband to a third-party
processor for AM/FM HD radio processor for IBOC signal processing (Si4777 only). The Si4777 provide a 500 kHz
BW signal for FM IBOC signal processing and a 30 kHz BW signal for AM IBOC signal processing. The ZIF I/Q 4pin interface consists of two data serial lines containing I and Q data, a bit clock, and a word frame for each data
sample. The interface operates in master mode and supports five different data formats:
I2S
ZIF
Left-Justified
ZIF
Right-Justified ZIF
DSP ZIF
DSP Left-Justified ZIF
Table 4. ZIF I/Q Interface Description
Pin
Description
IOUT
16-bit baseband I word
QOUT
16-bit baseband Q word
IQFS
Word frame sync for I and Q words
IQCLK
Bit clock for I and Q data
7.1. ZIF I/Q Data Formats
In I2S format, by default, the MSB is captured on the second rising edge of IQCLK following each IQFS transition.
The remaining bits of the word are sent in order, down to the LSB.
In Left-Justified format, by default, the MSB is captured on the first rising edge of IQCLK following each IQFS
transition. The remaining bits of the word are sent in order, down to the LSB.
In Right-Justified format, by default, the LSB is captured on the last rising edge of IQCLK in each valid IQFS
interval.
In DSP format, the IQFS becomes a pulse with a width of 1 IQCLK period. There are two options in transferring the
digital baseband I/Q data in DSP format: the MSB of I and Q data can be transferred on the first rising edge of
IQCLK following the IQFS pulse (left-justified DSP format) or on the second rising edge.
In all data formats, depending on the word size, IQCLK frequency, and sample rates, there may be unused IQCLK
cycles after the LSB of each word before the next IQFS transition and MSB of the next word. In addition, if
preferred, the user can configure the MSB to be captured on the falling edge of IQCLK via properties. The number
of baseband I/Q bits is configured for 16 bits.
18
Rev. 0.3
AN645
IQCLK
Sample n
IQFS
Sample n+1
1 IQCLK
1 IQCLK
1
IOUT
2
n-2
3
n-1
MSB
QOUT
1
2
n-2
3
n
1
LSB
MSB
n
1
LSB
MSB
n-1
MSB
2
n-2
3
n-1
n
LSB
2
n-2
3
n-1
n
LSB
Figure 9. I2S ZIF Format
IQCLK
IQFS
IOUT
Sample n
1
2
3
Sample n+1
n-2
n-1
MSB
QOUT
1
2
3
n-2
n-1
MSB
n
1
LSB
MSB
n
1
LSB
MSB
2
n-2
3
n-1
n
LSB
2
n-2
3
n-1
n
LSB
Figure 10. Left-Justified ZIF Format
IQCLK
IQFS
IOUT
Sample n
1
2
3
Sample n+1
n-2
n-1
MSB
QOUT
1
MSB
2
3
n-2
n-1
n
1
LSB
MSB
n
1
LSB
MSB
2
3
n-2
n-1
n
LSB
2
3
n-2
n-1
n
LSB
Figure 11. Right-Justified ZIF Format
Rev. 0.3
19
AN645
IQCLK
IQFS
Sample n
1 IQCLK
IOUT
(MSB at 2nd rising edge)
1
2
3
Sample n+1
n-2
n-1
MSB
n
1
LSB
MSB
2
3
QOUT
(MSB at 2nd rising edge)
1
2
3
n-1
Sample n+1
n-2
n-1
MSB
n
1
LSB
MSB
2
3
n-2
n-1
IQCLK
IQFS
Sample n
1
2
3
Sample n+1
n-2
n-1
MSB
n
1
LSB
MSB
2
1
MSB
2
3
n-1
n
LSB
Sample n+1
n-2
n-1
n
LSB
1
2
3
MSB
Figure 13. DSP Left-Justified ZIF Format
20
n-2
3
Sample n
QOUT
(MSB at 1st rising edge)
Rev. 0.3
n
LSB
Figure 12. DSP ZIF Format
IOUT
(MSB at 1st rising edge)
n
LSB
Sample n
1 IQCLK
n-2
n-2
n-1
n
LSB
AN645
7.2. ZIF I/Q Sample Rates and Clocking Requirements
The device supports a number of industry-standard sampling rates including 650, 675, and 744.1875 kHz.
The external crystal and/or reference clock frequency must be the following to support the following ZIF I/Q
samples rates for interface to an HD radio demodulator/decoder or DSP.
Table 5. Crystal/Reference Clock Frequency Requirements for the ZIF I/Q Sample Rates and
Bit Clock Rates Supported
RCLK/XTAL
Frequency (MHz)
36.4000
37.8000
37.209375
IQFS ZIF I/Q
Sample Rate (kHz)
IQCLK
I/Q Bit Clock (MHz)
Broadcast Reception
Modes
650.0000
10.4000
AM/FM HD-Radio
325.0000
5.2000
FM Analog
40.6250
2.2750
AM Analog
675.0000
10.8000
AM/FM HD-Radio
337.5000
5.4000
FM Analog
42.1875
2.3625
AM Analog
744.1875
14.88375
AM/FM HD-Radio
372.0938
7.4419
FM Analog
46.5117
1.8605
AM Analog
Sample n
1
2
3
Sample n+1
n-2
n-1
MSB
n
1
LSB
MSB
2
3
MSB
2
3
n-1
n
LSB
Sample n
1
n-2
Sample n+1
n-2
n-1
n
LSB
Rev. 0.3
1
MSB
2
3
n-2
n-1
n
LSB
21
AN645
8. Timing
8.1. Command and Property Timing
When the user reads a response over the I2C bus, the first 8 bits returned are the STATUS register. Bit 7 of the
STATUS register is the CTS bit (Clear to Send). When CTS is 1, it indicates that the chip is ready to receive a new
command. Seek and Tune commands may take longer to complete than most other commands, so they also use
the STC bit (Seek/Tune Complete) to indicate they have completed. STC is bit 0 of the STATUS register.
When the user sends any command, the CTS bit will immediately reset to 0. CTS will remain 0 while the chip
processes the command. When the chip is finished processing the command, the CTS bit will be set back to 1.
Before sending another command, the user may poll CTS by reading the first byte of response until CTS=1. If the
user has enabled the optional CTS interrupt, then the INTB pin will pulse low immediately after CTS has been set to
1, to notify the user that the previous command has completed. For information on how to enable the CTS interrupt,
see the INT_CTL_ENABLE property and CTSIEN bit in the arguments for the POWER_UP command.
The commands for seek and tune (FM_TUNE_FREQ, FM_SEEK_START, etc.) will cause CTS to reset to 0 for a
short time, but they will set CTS back to 1 after the seek or tune has started. The seek or tune is progressing even
though CTS has been set back to 1. Although the user is free to send another command at this time, it is highly
recommended to wait until the STC (Seek/Tune Complete) bit has been set to 1 before sending another command.
The only exception is the AM/FM/WB_RSQ_STATUS command, which may be sent at any time because it can be
used to cancel the seek/tune in progress and check the status of which station seek is currently on.
When the seek/tune completes, the STC bit will be set to 1. The user may poll STC by reading the first byte of
response until STC=1. If the user has enabled the optional STC interrupt, then the INTB pin will pulse low
immediately after STC has been set to 1, to notify the user that the seek or tune has completed. For information on
how to enable the STC interrupt, see the INT_CTL_ENABLE property.
After the seek or tune has completed, the user may acknowledge the completion by sending the AM/FM/
WB_RSQ_STATUS command with the STCACK bit set to 1. This will reset the STC bit back to 0. After this, the user
may send another seek or tune command. Alternatively a new seek or tune command will also clear the STC bit
when it begins.
Figure 14 shows a seek or tune command with the optional CTS and STC interrupts enabled. The timing
parameters are shown in Table 6.
Control
Bus
Command
Command
FM_TUNE_FREQ
FM_RSQ_STATUS
CTS
Bit
STC
Bit
INTB
tINT
tCTS
tSTC
Figure 14. CTS and STC Timing Model
22
Rev. 0.3
AN645
Table 6. Command Timing Parameters for Common Commands
Command
tCTS
tSTC
tINT
POWER_UP
100 ms
—
3 µs
POWER_DOWN
<1000 ms
—
3 µs
FUNC_INFO
<200 µs
—
3 µs
SET_PROPERTY
<200 µs
—
3 µs
GET_PROPERTY
<200 µs
—
3 µs
GET_INT_STATUS
<200 µs
—
3 µs
AGC_STATUS
<200 µs
—
3 µs
DIG_AUDIO_PIN_CFG
<200 µs
—
3 µs
ZIF_PIN_CFG
<200 µs
—
3 µs
GPIO_CTL_PIN_CFG
<200 µs
—
3 µs
ANA_AUDIO_PIN_CFG
<200 µs
—
3 µs
Table 7. Command Timing Parameters for FM Receiver
Command
tCTS
tSTC
tINT
FM_TUNE_FREQ
<200 µs
21 ms
3 µs
FM_TUNE_FREQ (fast tune)
<200 µs
5 ms
3 µs
FM_SEEK_START
<200 µs
See Note below.
3 µs
FM_RSQ_STATUS
<200 µs
—
3 µs
FM_ACF_STATUS
<200 µs
—
3 µs
FM_RDS_STATUS
<200 µs
—
3 µs
FM_RDS_BLOCKCOUNT
<200 µs
—
3 µs
*Note: tSTC is seek time per channel. Total seek time depends on bandwidth, channel spacing, and
number of channels to next valid channel.
Worst case seek time complete for FM_SEEK_START is
– FM_SEEK_BAND_BOTTOM
  FM_SEEK_BAND_TOP

-------------------------------------------------------------------------------------------------------------------------------------------------
 + 1  t STC
FM_SEEK_FREQ_SPACING
The seek time will require an additional 26 ms for channel spacings other than 200 kHz
Rev. 0.3
23
AN645
Table 8. Command Timing Parameters for AM Receiver
Command
tCTS
tSTC
tINT
AM_TUNE_FREQ
100 µs
40 ms
3 µs
AM_SEEK_START
100 µs
See Note below.
3 µs
AM_RSQ_STATUS
100 µs
—
3 µs
AM_ACF_STATUS
100 µs
—
3 µs
*Note: tSTC is seek time per channel. Total seek time depends on bandwidth, channel spacing, and
number of channels to next valid channel.
8.2. Fast Tune Timing
The timing diagram for fast tune is shown in Figure 15.
F1
}
F1
F2
F2
Audio
Audio
T2
T1
T1
Fast Tune
command
issued
Fast Tune
Initiated
T1 ~ 0.5 ms
T2 ~ 1 ms
Figure 15. Fast Tune Timing Diagram
24
Rev. 0.3
AN645
9. Commands and Properties
9.1. Common Commands and Properties
The following properties and commands are common to all receiver modes.
Table 9. Common Receiver Command Summary
Number
Name
Summary
0x01
POWER_UP
Power-up device and mode selection. Modes include operational
function (AM, FM) and audio interface configuration.
0x02
PART_INFO
Returns the part information of the device.
0x11
POWER_DOWN
0x12
FUNC_INFO
0x13
SET_PROPERTY
Sets the value of a property.
0x14
GET_PROPERTY
Retrieve a property's value.
0x15
GET_INT_STATUS
Read interrupt status bits.
0x17
AGC_STATUS
0x18
DIG_AUDIO_PIN_CFG
0x19
ZIF_PIN_CFG
0x1A
GPIO_CTL_PIN_CFG
0x1B
ANA_AUDIO_PIN_CFG
0x1C
INTB_PIN_CFG
Power-down the device.
Returns the firmware revision and patch revision.
Reports the status of the AGC.
Configures the digital audio pins.
Configures the digital I/Q pins. (Si4777 only)
Configures GPIO1 and GPIO2 pins.
Configures the analog audio pins.
Configures behavior of INTB and A1 pins.
Table 10. Common Receiver Property Summary
Number
Name
Default
0x0000
INT_CTL_ENABLE
0x0200
DIGITAL_IO_INPUT_SAMPLE_RATE
0x0201
DIGITAL_IO_INPUT_FORMAT
0x0202
DIGITAL_IO_OUTPUT_SAMPLE_RATE
0x0203
DIGITAL_IO_OUTPUT_FORMAT
0x0000
0
Summary
Interrupt enable property.
0xBB80 Sets the digital input sample rate in units of
48000 Hz. (Si4777 only)
0x3600
13824
Configures digital audio input format.
(Si4777 only)
0xBB80 Sets the digital output sample rate in units of
48000 Hz.
0x3600
13824
Rev. 0.3
Configures digital audio output format.
25
AN645
Table 10. Common Receiver Property Summary (Continued)
Number
Name
Default
0x0300
AUDIO_ANALOG_VOLUME
0x0301
AUDIO_MUTE
0x0600
ZIF_OUTPUT_CFG
0x003F
63
0x0000
0
0X0801
2049
Summary
Sets the analog audio volume.
Audio mute property.
Enables or disables ZIF and configures ZIF
interface format (Si4777only).
Table 11. Status Response for the FM Receiver
26
Bit
7
6
STATUS
CTS
ERR
5
4
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
Bit
Name
Function
7
CTS
Clear to Send.
0 = Wait before sending next command.
1 = Clear to send next command.
6
ERR
Error.
0 = No error.
1 = Error.
5:4
Reserved
Values may vary.
3
RSQINT
Received Signal Quality Interrupt.
0 = Received Signal Quality measurement has not been triggered.
1 = Received Signal Quality measurement has been triggered.
2
RDSINT
Radio Data System Interrupt.
0 = Radio data system interrupt has not been triggered.
1 = Radio data system interrupt has been triggered.
1
ACFINT
Automatically Controlled Features Interrupt.
0 = ACF measurement has not been triggered.
1 = ACF measurement has been triggered.
0
STCINT
Seek/Tune Complete Interrupt.
0 = Tune complete has not been triggered.
1 = Tune complete has been triggered.
Rev. 0.3
AN645
Table 12. Status Response for the AM Receiver
Bit
7
6
STATUS
CTS
ERR
5
4
XX
3
2
1
0
RSQINT
X
ACFINT
STCINT
Bit
Name
7
CTS
Clear to Send.
0 = Wait before sending next command.
1 = Clear to send next command.
6
ERR
Error
0 = No error.
1 = Error.
5:4
Reserved
Values may vary.
3
RSQINT
Received Signal Quality Interrupt
0 = Received Signal Quality measurement has not been triggered.
1 = Received Signal Quality measurement has been triggered.
2
Reserved
Value may vary.
1
ACFINT
Automatically Controlled Features Interrupt.
0 = ACF measurement has not been triggered.
1 = ACF measurement has been triggered.
STCINT
Seek/Tune Complete Interrupt.
0 = Tune complete has not been triggered. Do not send a new TUNE/SEEK
command.
1 = Tune complete has been triggered. It is safe to send a new TUNE/
SEEK command.
0
Function
Rev. 0.3
27
AN645
If the ERR bit in the STATUS response is set for a command or property, the response is redefined as follows:
Table 13. Response When ERR Bit is Set
Bit
STATUS
7
6
CTS
1
5
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
ERROR
RESP1
RESP
1
28
4
Bit
Name
7:0
ERROR
Rev. 0.3
Function
Error definitions.
0x10=Bad command.
0x11=Bad ARG1.
0x12=Bad ARG2.
0x13=Bad ARG3.
0x14=Bad ARG4.
0x18=Command busy.
0x20=Bad internal memory.
0x30=Bad patch.
0x31=Bad boot mode.
0x40=Bad property.
AN645
9.1.1. Common Receiver Commands
Command 0x01 POWER_UP
The POWER_UP command initiates the boot process to move the device from powerdown to powerup mode. The
boot can occur from internal device memory or a system controller downloaded patch. This command powers up
the device with the specified function (FM Receive, AM Receive). Power-up is complete when the CTS bit is set.
This is the only command that may be sent while the device is powered down.
Command
Bit
7
6
5
4
IBIAS7X
CTSIEN
INTSEL
0
XIBIASHC
0
Bit
7
XIBIAS[2:0]
FREQ[3:0]
00010
ARG5
1
FASTBOOT
FUNC[3:0]
ARG4
ARG
1
XSTART
XCLOAD[5:0]
00
ARG2
ARG3
2
0x01
CMD
ARG1
3
XMODE[2:0]
Name
Function
IBIAS7X
Crystal 7x bias current.
0=All other configurations.
1=Receiver 1 in a two/three receiver configuration with 37.209375, 36.4,
or 37.8 MHz crystal.
1
6:0
XSTART
Oscillator Startup.
0010001=Start up multiple tuner.
1110111=Normal operation.
2
7:6
Reserved
Always write 00.
Selects the amount of additional on-chip capacitance to be connected
between XTAL1 and gnd and between XTAL2 and gnd. One half of the
capacitance value shown here is the additional load capacitance presented to the xtal. The minimum step size is 0.277 pF. The required
value will be layout-dependent. Range is 0–0x3F i.e.(0–16.33 pF) The
Si477x EVB sets XCLOAD=0x28.
2
5:0
XCLOAD[5]
3
7
CTSIEN
CTS interrupt enable.
0=Disable.
1=Enable.
3
6
INTSEL
CTS interrupt pin select.
0=A1 pin.
1=INTB pin.
3
5
FASTBOOT
3
3
XIBIASHC
Speeds boot time when set. It is recommended to set this bit with all
crystals.
Crystal high current.
0=Single receiver configuration.
1=Multiple receiver configuration.
Rev. 0.3
29
AN645
ARG
Bit
Name
3
2:0
XIBIAS
4
7:4
FUNC[3:0
Function
Crystal bias current.
0=37.209375, 36.4, or 37.8 MHz crystal or external clock.
7=37.209375, 36.4, or 37.8 MHz crystal.
Selects the boot function of the device.
0 = Boot Loader.
1 = FM Receive.
2 = AM Receive.
Note: Values other than those listed may result in unpredictable behavior.
30
4
3:0
FREQ[3:0]
Selects the crystal frequency.
1 = 37.209375 MHz.
2 = 36.4 MHz.
3 = 37.8 MHz.
5
4
Reserved
Always write 00010.
5
2:0
XMODE[2:0]
Crystal mode.
1=Crystal.
2=External clock.
Rev. 0.3
AN645
Command 0x02 PART_INFO
The PART_INFO command returns the chip revision, part firmware major, minor, and build revision, and ROM ID.
The command is complete when the CTS bit (and optional interrupt) is set. The command may only be sent in
powerup mode.
Command
Bit
7
6
5
4
3
2
1
0
0x02
CMD
Response
Bit
7
6
STATUS
CTS
ERR
5
4
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
RESP1
CHIPREV[7:0]
RESP1
PART[7:0]
RESP3
PMAJOR[7:0]
RESP4
PMINOR[7:0]
RESP5
PBUILD[7:0]
RESP6
Reserved
RESP7
Reserved
RESP8
ROMID[7:0]
RESP
Bit
Name
Function
1
7:0
CHIPPREV
Chip Revision
2
7:0
PART
Part Number, last two digits of part number
3
7:0
PMAJOR
Part Major Revision
4
7:0
PMINOR
Part Minor Revision
5
7:0
PBUILD
Part Build Version
6
7:0
Reserved
Values may vary.
7
7:0
Reserved
Values may vary.
8
7:0
ROMID
ROM ID
Rev. 0.3
31
AN645
Command 0x11 POWER_DOWN
The POWER_DOWN command moves the device from powerup to powerdown mode. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This command may only be sent when in powerup
mode. Note that only the POWER_UP command is accepted in powerdown mode. If the system controller writes a
command other than POWER_UP when in powerdown mode, the device will not respond. The device will only
respond when a POWER_UP command is written. It is possible to power down a device and leave the oscillator
running. This may be desirable in multiple receiver applications in which the device driving the oscillator for other
devices is to be placed in powerdown without affecting the other devices.
Command
Bit
7
6
5
4
3
2
1
0
0x11
CMD
0
ARG1
ARG
Bit
Name
1
7:0
Reserved
2
0
XOSC
XOSC
Function
Always write 0.
0=Full powerdown.
1=Powerdown and leave oscillator running.
Response
Bit
7
6
STATUS
CTS
ERR
5
4
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
Note: The above response shows status bits for FM Receive mode (see Table 11). See Table 12 for status bits for AM
Receive mode.
32
Rev. 0.3
AN645
Command 0x12 FUNC_INFO
The FUNC_INFO command returns the firmware revision and patch revision for currently-loaded functional mode
firmware (AM, FM). The command is complete when the CTS bit (and optional interrupt) is set. This command may
only be sent in powerup mode.
Command
Bit
7
6
5
4
3
2
1
0
0x12
CMD
Response
Bit
7
6
STATUS
CTS
ERR
5
4
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
RESP1
FWMAJOR[7:0]
RESP2
FWMINOR1[7:0]
RESP3
FWMINOR2[7:0]
RESP4
PATCHH[7:0]
RESP5
PATCHL[7:0]
RESP6
FUNC[7:0]
Note: The above response shows status bits for FM Receive mode (see Table 11 on page 26). See Table 12 on page 27 for
status bits for AM Receive mode.
RESP
Bit
Name
Function
1
7:0
FWMAJOR[7:0]
Firmware Major Revision.
2
7:0
FWMINOR1[7:0]
Firmware Minor1 Revision.
3
7:0
FWMINOR2[7:0]
Firmware Minor2 Revision.
4
7:0
PATCHH[7:0]
Patch ID High Byte (HEX).
5
7:0
PATCHL[7:0]
Patch ID Low Byte (HEX).
6
7:0
FUNC[7:0]
Returns the current functional mode:
1 FM Receive
2 AM Receive
Rev. 0.3
33
AN645
Command 0x13 SET_PROPERTY
The SET_PROPERTY command sets the value of a property. The CTS bit (and optional interrupt) is set when it is
safe to send the next command. This command may only be sent in powerup mode.
Command
Bit
7
6
5
4
3
CMD
0x13
ARG1
00000000
ARG2
PROPH[7:0]
ARG3
PROPL[7:0]
ARG4
PROPDH[7:0]
ARG5
PROPDL[7:0]
2
1
0
ARG
Bit
Name
Function
1
7:0
Reserved
2
7:0
PROPH
[7:0]
Property Address High Byte
This byte, in combination with PROPL, is used to specify the property to modify.
3
7:0
PROPL
[7:0]
Property Address Low Byte
This byte, in combination with PROPH, is used to specify the property to modify.
4
7:4
PROPDH
[7:0]
Property Value High Byte
This byte, in combination with PROPDL, is used to set the property value.
5
7:0
PROPDL
[7:0]
Property Value Low Byte
This byte, in combination with PROPDH, is used to set the property value.
Always write to 0.
Response
Bit
7
6
STATUS
CTS
ERR
5
4
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
Note: The above response shows status bits for FM Receive mode (see Table 11 on page 26). See Table 12 on page 27 for
status bits for AM Receive mode.
34
Rev. 0.3
AN645
Command 0x14 GET_PROPERTY
The GET_PROPERTY command retrieves a property's value. The CTS bit (and optional interrupt) is set when it is
safe to send the next command. This command may only be sent in powerup mode
Command
Bit
7
6
5
4
3
CMD
0x14
ARG1
00000000
ARG2
PROPH[7:0]
ARG3
PROPL[7:0]
ARG
Bit
Name
1
7:0
Reserved
2
1
0
Function
Always write 0.
2
7:0
PROPH[7:0]
Property Address High Byte.
This byte, in combination with PROPL, is used to specify
the property to get.
3
7:0
PROPL[7:0]
Property Address Low Byte.
This byte, in combination with PROPH, is used to specify
the property to get.
Response
Bit
7
6
5
STATUS
CTS
ERR
4
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
RESP1
XXXXXXXX
RESP2
PROPDH[7:0]
RESP3
PROPDL[7:0]
Note: The above response shows status bits for FM Receive mode (see Table 11 on page 26). See Table 12 on page 27 for
status bits for AM Receive mode.
RESP
Bit
Name
Function
1
7:0
Reserved
2
7:0
PROPDH[7:0]
Property Value High Byte.
This byte, in combination with PROPDL, represents
the requested property value.
3
7:0
PROPDL[7:0]
Property Value Low Byte.
This byte, in combination with PROPDH, represents
Response values may vary.
the requested property value.
Rev. 0.3
35
AN645
Command 0x15 GET_INT_STATUS
The GET_INT_STATUS command updates the bits of the status byte. This command should be called after any
command that sets the STCINT, ACFINT, RDSINT, ASQINT, or RSQINT bits. When polling, this command should
be periodically called to monitor the STATUS byte, and, when using interrupts, this command should be called after
the interrupt is set to update the STATUS byte. The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This command may only be set in powerup mode.
Command
Bit
7
6
5
4
3
2
1
0
0x15
CMD
Response
Bit
7
6
STATUS
CTS
ERR
5
4
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
Note: The above response shows status bits for FM Receive mode (see Table 11 on page 26). See Table 12 on page 27 for
status bits for AM Receive mode.
Command 0x17 AGC_STATUS
The AGC_STATUS command reports the current status of the AGC for FM mode. The command is complete when
the CTS bit (and optional interrupt) is set. This command may only be sent when in powerup mode.
Bit
7
6
5
4
2
1
0
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
LNAHI
LNALO
X
X
0x17
CMD
RESP
7
6
STATUS
CTS
ERR
RESP1
3
XX
5
4
XX
MIXHI
MXLO
RESP2
FMAGC1
RESP3
FMAGC2
RESP4
PGAGAIN
RESP5
FMLNAG
Note: The above response shows status bits for FM Receive mode (see Table 11 on page 26). See Table 12 on page 27 for
status bits for AM Receive mode.
36
Rev. 0.3
AN645
RESP
Bit
Name
1
7:6
Reserved
1
5
MXHI
0 = FM Mixer PD high threshold is not tripped.
1 = FM Mixer PD high threshold is tripped.
1
4
MXLO
0 = FM Mixer PD low threshold is not tripped.
1 = FM Mixer PD low threshold is tripped.
1
3
LNAHI
0 = FM LNA PD high threshold is not tripped.
1 = FM LNA PD high threshold is tripped.
1
2
LNALO
0 = FM LNA PD low threshold is not tripped.
1 = FM LNA PD low threshold is tripped.
1
1:0
Reserved
Values may vary.
FMAGC1
The parallel combination of these resistors indicates
the current FMAGC1 attenuator resistance. The total
resistance value at the pin is 800/FMAGC1.
0 = 10 k—no attenuation
1 = 800 
2 = 400 
4 = 200 
8 = 100 
16 = 50 
32 = 25 
64 = 12.5 
128 = 6.25 
2
7:0
Function
Values may vary.
3
7:0
FMAGC2
The parallel combination of these resistors indicates
the current FMAGC2 attenuator resistance. The total
resistance value at the pin is 800/FMAGC2.
0 = 10 k—no attenuation
1 = 800 
2 = 400 
4 = 200 
8 = 100 
16 = 50 
32 = 25 
64 = 12.5 
128 = 6.25 
4
7:0
PGAGAIN
PGA gain in dB
Range: 8–33
5
7:0
FMLNAG
FM LNA Gain in dB
Range: 2–14
Rev. 0.3
37
AN645
Command 0x18 DIG_AUDIO_PIN_CFG
The DIG_AUDIO_PIN_CFG command configures the digital audio pins. Ensure that DCLK and DFS are stable
before this command is sent. Writing an argument byte to a non-zero value will change the state of a pin. Writing an
argument byte to 0 will not change the state of the pin and is useful when using this command to query the state of
the pins. The command is complete when the CTS bit (and optional interrupt) is set. This command may only be
sent in powerup mode.
Command
Bit
7
6
5
4
2
1
0
0x18
CMD
ARG1
0
DCLK[6:0]
ARG2
0
DFS[6:0]
ARG3
0
DOUT[6:0]
ARG4
0
BLEND[6:0]
ARG
Bit
Name
1
7
Reserved
Always write 0.
Function
1
6:0
DCLK[6:0]
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is completely
inactive. 1 M pull down is enabled.
10 = Configure this pin as part of the digital audio interface in slave
mode.
2
7
Reserved
Always write 0.
2
6:0
DFS[6:0]
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is completely
inactive. 1 M pull down is enabled.
10 = Configure this pin as part of the digital audio interface in slave
mode.
3
7
Reserved
Always write 0.
3
6:0
DOUT[6:0]
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is completely
inactive. 1 M pull down is enabled.
12 = Configure this pin as digital out on I2S port 1.
13 = Configure this pin as digital in on I2S port 1. (Si4777 only)
4
7
Reserved
Always write 0.
4
38
3
6:0
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is completely
inactive. 1 M pull down is enabled.
BLEND[6:0]
13 = Configure this pin as digital in on I2S port 1. (Si4777 only)
23 = Configure this pin as the input that selects the mode of the I2S
audio combiner (analog or HD) (Si4777 only).
Rev. 0.3
AN645
Response
Bit
7
6
5
4
STATUS
CTS
ERR
RESP1
Reserved
DCLK[6:0]
RESP2
Reserved
DFS[6:0]
RESP3
Reserved
DOUT[6:0]
RESP4
Reserved
BLEND[6:0]
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
Note: The above response shows status bits for FM Receive mode (see Table 11 on page 26). See Table 12 on page 27 for
status bits for AM Receive mode.
RESP
Bit
Name
Function
1
7
Reserved
Values may vary.
1
6:0
DCLK[6:0]
1 = Disabled.
10 = Configured as part of the digital audio interface
in slave mode.
2
7
Reserved
Values may vary.
2
6:0
DFS[6:0]
1 = Disabled.
10 = Configured as part of the digital audio interface
in slave mode.
3
7
Reserved
Values may vary.
3
6:0
DOUT[6:0]
1 = Disabled.
12 = Configured as digital out on I2S port 1.
13 = Configured as digital in on I2S port 1. (Si4777
only)
4
7
Reserved
Values may vary.
4
6:0
BLEND[6:0]
1 = Disabled.
13 = Configured as digital in on I2S port 1.
23 = Configured as the input that selects the mode of
the I2S audio combiner (analog or HD).
(Si4777 only)
Rev. 0.3
39
AN645
Command 0x19 ZIF_PIN_CFG
(Si4777 Only)
The ZIF_PIN_CFG command configures the digital I/Q pins. Writing an argument byte to a non-zero value will
change the state of a pin. Writing an argument byte to 0 will not change the state of the pin and is useful when
using this command to query the state of the pins.The command is complete when the CTS bit (and optional
interrupt) is set. This command may only be sent in powerup mode.
Command
Bit
7
6
5
4
2
1
0
0x19
CMD
ARG1
0
IQCLK[6:0]
ARG2
0
IQFS[6:0]
ARG3
0
IOUT[6:0]
ARG4
0
QOUT[6:0]
ARG
Bit
Name
1
7
Reserved
Function
Always write 0.
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is completely inactive. 1 M pull down is enabled.
21 = Configure this pin as part of the I/Q interface in master
mode.
1
6:0
IQCLK[6:0]
2
7
Reserved
Always write 0.
2
6:0
IQFS[6:0]
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is completely inactive. 1 M pull down is enabled.
21 = Configure this pin as part of the I/Q interface in master
mode.
3
7
Reserved
Always write 0.
3
6:0
IOUT[6:0]
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is completely inactive. 1 M pull down is enabled.
22 = Configure this pin as I out.
4
7
Reserved
Always write 0.
QOUT[6:0]
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is completely inactive. 1 M pull down is enabled.
22 = Configure this pin as Q out.
4
40
3
6:0
Rev. 0.3
AN645
Response
Bit
7
6
5
4
STATUS
CTS
ERR
RESP1
Reserved
IQCLK[6:0]
RESP2
Reserved
IQFS[6:0]
RESP3
Reserved
IOUT[6:0]
RESP4
Reserved
QOUT[6:0]
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
Note: The above response shows status bits for FM Receive mode (see Table 11 on page 26). See Table 12 on page 27 for
status bits for AM Receive mode.
RESP
Bit
Name
Function
1
7
Reserved
1
6:0
IQCLK[6:0]
2
7
Reserved
Values may vary.
2
6:0
IQFS[6:0]
1 = Disabled.
21 = Configured as part of the I/Q interface in master
mode.
3
7
Reserved
Values may vary.
3
6:0
IOUT[6:0]
1 = Disabled.
22 = Configured I out.
4
7
Reserved
Values may vary.
4
6:0
QOUT[6:0]
1 = Disabled.
22 = Configured Q out.
Values may vary.
1 = Disabled.
21 = Configured as part of the I/Q interface in master
mode.
Rev. 0.3
41
AN645
Command 0x1A GPIO_CTL_PIN_CFG
Configures the state (high or low) of GPO1 and GPO2 pins. The command is complete when the CTS bit (and
optional interrupt) is set. This command may only be sent in powerup mode.
Command
Bit
7
6
5
4
2
1
0
0x1A
CMD
ARG1
Reserved
ICIN [6:0]
ARG2
Reserved
ICIP [6:0]
ARG3
Reserved
ICON[6:0]
ARG4
Reserved
ICOP[6:0]
ARG
Bit
Name
1
7
Reserved
Always write 0.
Function
1
6:0
ICIN [6:0]
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is completely inactive. 1 M pull down in enabled.
2 = Configure this pin as an output (GPO1) and drive it low.
3 = Configure this pin as an output (GPO1) and drive it high.
2
7
Reserved
Always write 0.
2
6:0
ICIP [6:0]
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is completely inactive. 1 M pull down in enabled.
2 = Configure this pin as an output (GPO2) and drive it low.
3 = Configure this pin as an output (GPO2) and drive it high.
3
7
Reserved
Always write 0.
3
6:0
ICON[6:0]
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is completely inactive. 1 M pull down in enabled.
10 = Configure this pin as part of the digital audio interface in
slave mode (DCLK). (Si4777 only).
4
7
Reserved
Always write 0.
ICOP[6:0]
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is completely inactive. 1 M pull down in enabled.
14 = Configure this pin as part of the digital audio interface in
slave mode (DOUT). (Si4777 only).
4
42
3
6:0
Rev. 0.3
AN645
Response
Bit
7
6
5
4
STATUS
CTS
ERR
RESP1
Reserved
ICIN[6:0]
RESP2
Reserved
ICIP[6:0]
RESP3
Reserved
ICON[6:0]
RESP4
Reserved
ICOP[6:0]
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
Note: The above response shows status bits for FM Receive mode (see Table 11 on page 26). See Table 12 on page 27 for
status bits for AM Receive mode.
RESP
Bit
Name
Function
1
7
Reserved
Values may vary.
1
6:0
ICIN[6:0]
1 = Disabled.
2 = GPO1 output, Driving low.
3 = GPO1 output, Driving high.
2
7
Reserved
Values may vary.
2
6:0
ICIP[6:0]
1 = Disabled.
2 = GPO2 output, Driving low.
3 = GPO2 output, Driving high.
3
7
Reserved
Values may vary.
3
6:0
ICON[6:0]
1 = Disabled.
10 = Configured as part of the digital audio interface in
slave mode on I2S port 2. (DCLK). (Si4777 only)
4
7
Reserved
Values may vary.
4
6:0
ICOP[6:0]
1 = Disabled.
14 = Configured as digital out on I2S port 2 (DOUT).
(Si47777 only).
Rev. 0.3
43
AN645
Command 0x1B ANA_AUDIO_PIN_CFG
The ANA_AUDIO_PIN_CFG command configures the analog audio pins. Writing an argument byte to 0 will not
change the state of the pin and is useful when using this command to query the state of the pins. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup
mode.
Command
Bit
7
6
5
4
2
1
0
0x1B
CMD
ARG1
0
ARG
Bit
Name
1
7
Reserved
1
3
LROUT[6:0]
6:0
Function
Always write 0.
LROUT[6:0]
0 = Do not modify the behavior of this pin.
1 = Disable the output drivers, so the pins are completely inactive and can be left floating.
2 = Configure the LOUT/ROUT pins to output audio.
3 = Configure LOUT for MPX and disable ROUT.
4 = Configure LOUT/ROUT for HD Split mode: ROUT = Analog out; LOUT = HD out.
Response
Bit
7
6
STATUS
CTS
ERR
RESP1
X
5
4
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
LROUT[6:0]
Note: The above response shows status bits for FM Receive mode (see Table 11 on page 26). See Table 12 on page 27 for
status bits for AM Receive mode.
RESP
Bit
Name
1
7
Reserved
1
44
6:0
LROUT[6:0]
Function
Values may vary.
1 = The output drivers are disabled, so the pins are completely inactive and can be left floating.
2 = LOUT/ROUT pins configured to output audio.
3 = LOUT is configured for MPX out and ROUT is disabled.
Rev. 0.3
AN645
Command 0x1C INTB_PIN_CFG
The INTB_PIN_CFG command configures INTB and A1 pins. Writing an argument byte to 0 will not change the
state of the pin and is useful when using this command to query the state of the pins. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode.
Command
Bit
7
6
5
4
3
2
1
0
0x1C
CMD
ARG1
Reserved
INTB[6:0]
ARG2
Reserved
A1[6:0]
ARG
Bit
Name
Function
1
7
Reserved
Always write to 0.
1
6:0
INTB[6:0]
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is
completely inactive and can be left floating.
10 = Configure this pin as part of the digital audio interface in slave mode.
40 = Configure this pin as the interrupt.
2
7
Reserved
Always write to 0.
2
6:0
0 = Do not modify the behavior of this pin.
1 = Disable both the output and input drivers so the pin is
completely inactive and can be left floating.
40 = Configure this pin as the interrupt.
A1[6:0]
Response
Bit
7
6
5
4
Status
CTS
ERR
RESP1
Reserved
INTB[6:0]
RESP 2
Reserved
A1[6:0]
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
Note: The above response shows status bits for FM Receive mode (see Table 11 on page 26). See Table 12 on page 27 for
status bits for AM Receive mode.
Rev. 0.3
45
AN645
46
RESP
Bit
Name
Function
1
7
Reserved
Values may vary.
1
6:0
INTB[6:0]
1 = Disabled.
10 = Configured as part of the digital audio interface in
slave mode.
40 = Configured as the interrupt.
2
7
Reserved
Values may vary.
2
6:0
A1[6:0]
1 = Disabled.
40 = Configured as the interrupt.
Rev. 0.3
AN645
9.1.2. Common Receiver Properties
Property 0x0000 INT_CTL_ENABLE
The INT_CTL_ENABLE property enables top-level interrupt sources. The CTS bit (and optional interrupt) is set
when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0x0000
INT_CTL_ENABLE
15:13
12
11
10
9
000
ASQREP
RSQREP
RDSREP
ACFREP
000
0
0
0
0
8
7
6
STCREP CTSIEN ERRIEN
0
0
0
5
4
3
2
1
0
0
ASQIEN
RSQIEN
RDSIEN
ACFIEN
STCIEN
0
0
0
0
0
0
Bit
Name
Function
15:13
Reserved
Always write 0.
12
ASQREP
Repeat interrupt pulse when ASQINT is set, even if a previous interrupt was
generated but not acknowledged.
11
RSQREP
Repeat interrupt pulse when RSQINT is set, even if a previous interrupt was
generated but not acknowledged.
10
RDSREP
Repeat interrupt pulse when RDSINT is set, even if a previous interrupt was
generated but not acknowledged.
9
ACFREP
Repeat interrupt pulse when ACFINT is set, even if a previous interrupt was
generated but not acknowledged.
8
STCREP
Repeat interrupt pulse when STCIEN is set, even if a previous interrupt was
generated but not acknowledged.
7
CTSIEN
Interrupt when CTS is set.
6
ERRIEN
Interrupt when ERR is set.
5
Reserved
Always write 0.
4
ASQIEN
Interrupt when ASQINT is set.
3
RSQIEN
Interrupt when RSQIEN is set.
2
RDSIEN
Interrupt when RDSINT is set.
1
ACFIEN
Interrupt when ACFINT is set.
0
STCIEN
Interrupt when STCIEN is set.
Rev. 0.3
47
AN645
Property 0x0200 DIGITAL_IO_INPUT_SAMPLE_RATE (Si4777 only)
The DIGITAL_IO_INPUT_SAMPLE_RATE property sets the digital input sample rate in units of Hz. Set the sample
rate to 0 to disable digital audio. The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 48000
Units: Hz
DIGITAL_IO_INPUT_SAMPLE_RATE
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
INPUT_SAMPLE_RATE[15:0]
0xBB80
48
Bit
Name
Function
15:0
INPUT_SAMPLE_RATE[15:0]
Sets the digital input sample rate in units of Hz.
Default is 48000. Range is 32000–48000.
Rev. 0.3
AN645
Property 0x0201 DIGITAL_IO_INPUT_FORMAT (Si4777 only)
The DIGITAL_IO_INPUT_FORMAT property configures digital audio input format. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be sent. This property may only
be set or read in powerup mode.
Default: 0x3600
DIGITAL_IO_INPUT_FORMAT
15
14
0x0
13
12
11
SLOT_SIZE[2:0]
Bit
Name
15:14
Reserved
13:11
10:8
10
SLOT_SIZE[2:0]
SAMPL_SIZE[2:0]
BITORDER
6
SWAP
4:1
0
CLKINV
8
7
6
5
SAMPL_SIZE[2:0] BITORDER SWAP
7
5
9
CLKINV
4
3
2
1
0
FRAMING_MODE[3:0]
0
Function
Always write 0.
Defines the width of the data channel. This is only used in right justified
modes.
2 = 8 bits.
4 = 16 bits.
5 = 20 bits.
6 = 24 bits.
Determines the number of bits in a sample. Only the specified number of
bits per sample are used. The value of any bits sent over the sample size
will be 0. Default is 24 bits.
2 = 8 bits.
4 = 16 bits.
5 = 20 bits.
6 = 24 bits.
Determine if the MSB or LSB is transmitted first. Default is 0.
0 = Transmit MSB first.
1 = Transmit LSB first.
SWAP—Swap position of the left and right channels. Default is 0.
0 = Transmit the left sample first.
1 = Transmit the right sample first.
Inverts the data clock. Default is 0.
0 = The bit clock is not inverted. DFS will be captured on rising edge of
DCLK.
1 = The bit clock is inverted. DFS will be captured on falling edge of DCLK.
Determines when the data is transmitted relative to frame sync.
0x0 = I2S mode.
0x6 = DSP mode.
FRAMING_MODE[3:0]
0x7 = Left-justified DSP mode.
0x8 = Left-justified mode.
0x9 = Right-justified mode.
Reserved
Always write 0.
Rev. 0.3
49
AN645
Property 0x0202 DIGITAL_IO_OUTPUT_SAMPLE_RATE
The DIGITAL_IO_OUTPUT_SAMPLE_RATE property sets the digital output sample rate in units of Hz. The CTS
bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 48000
Units: Hz
DIGITAL_IO_OUTPUT_SAMPLE_RATE
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
OUTPUT_SAMPLE_RATE[15:0]
0xBB80
50
Bit
Name
Function
15:0
OUTPUT_SAMPLE_RATE[15:0]
Sets the digital output sample rate in units of
Hz. Default is 48000. Range is 32000–48000.
Rev. 0.3
AN645
Property 0x0203 DIGITAL_IO_OUTPUT_FORMAT
The DIGITAL_IO_OUTPUT_FORMAT property configures digital audio output format. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0x3600
DIGITAL_IO_OUTPUT_FORMAT
15
14
0x0
13
12
11
SLOT_SIZE[2:0]
Bit
Name
15:14
Reserved
13:11
10:8
10
SLOT_SIZE[2:0]
SAMPL_SIZE[2:0]
BITORDER
6
SWAP
4:1
0
CLKINV
8
7
6
5
SAMPL_SIZE[2:0] BITORDER SWAP
7
5
9
CLKINV
4
3
2
1
0
FRAMING_MODE[3:0]
0
Function
Always write 0.
Defines the width of the data channel. This is only used in right-justified
modes.
2 = 8 bits.
4 = 16 bits.
5 = 20 bits.
6 = 24 bits.
Determines the number of bits in a sample. Only the specified number of
bits per sample are used. The value of any bits sent over the sample size
will be 0. Default is 24 bits.
2 = 8 bits.
4 = 16 bits.
5 = 20 bits.
6 = 24 bits.
Determine if the MSB or LSB is transmitted first. Default is 0.
0 = Transmit MSB first.
1 = Transmit LSB first.
SWAP—Swap position of the left and right channels. Default is 0.
0 = Transmit the left sample first.
1 = Transmit the right sample first.
Inverts the data clock. Default is 0.
0 = The bit clock is not inverted. DFS will be captured on rising edge of
DCLK.
1 = The bit clock is inverted. DFS will be captured on falling edge of DCLK.
Determines when the data is transmitted relative to frame sync.
0x0 = I2S mode.
0x6 = DSP mode.
FRAMING_MODE[3:0]
0x7 = Left-justified DSP mode.
0x8 = Left-justified mode.
0x9 = Right-justified mode.
Reserved
Always write 0.
Rev. 0.3
51
AN645
Property 0x0300 AUDIO_ANALOG_VOLUME
The AUDIO_ANALOG_VOLUME property sets the analog audio volume. A value of 0 will mute the audio; a value
of 1 applies 62 dB of attenuation, and a value of 63 applies no attenuation. Each step accounts for 1 dB of change
in the output. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property
may only be set or read in powerup mode.
Default: 63
AUDIO_ANALOG_VOLUME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
0x000
VOL[5:0]
0x000
0x3F
Bit
Name
15:6
Reserved
Always write 0.
5:0
VOL[5:0]
Sets the analog audio volume. Default is 63. Range is 0–63.
1
0
Function
Property 0x0301 AUDIO_MUTE
The AUDIO_MUTE property mutes/unmutes each audio output (analog left or analog right).The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read when in
the powerup mode.
Default: 0x0000
AUDIO_MUTE
15
52
14
13
12
11
10
Bit
Name
15:2
Reserved
1
RIGHTMUTE
0
LEFTMUTE
9
8
7
6
5
4
3
2
1
0
0x0000
RIGHTMUTE
LEFTMUTE
0x0000
0
0
Function
Always write 0.
0 = Right audio is not muted.
1 = Right audio is muted.
0 = Left audio is not muted.
1 = Left audio is muted.
Rev. 0.3
AN645
Property 0x0600 ZIF_OUTPUT_CFG
(Si4777 Only)
The ZIF_OUTPUT_CFG property enables/disables ZIF and configures the ZIF interface format. The ZIF data rate
depends on RCLK and the radio's operational mode. Changes to this property will take effect at tune time.
The ZIF pins must also be configured, see ZIF_PIN_CFG on page 40. Refer to the Si477x data sheet for details on
interface format and data rates. The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be sent in power-up mode.
Default: 0x0801
ZIF_OUTPUT_CFG
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FILL[1:0]
RESERVED[7:0]
FALL
ZIF_FORMAT[3:0]
RESERVED
0x0
0x20
0
0x0
1
Bit
Name
15:14
FILL[1:0]
13:6
RESERVED[7:0]
5
FALL
4:1
ZIF_FORMAT[3:0]
0
RESERVED
Function
FILL[1:0]—Defines the fill value for unused data bits. Default 0.
0 = The unused bits are filled with 0s.
1 = The unused bits are filled with 1s.
2 = The unused bits are sign extended.
3 = The unused bits are filled with a random sequence.
Always write as 0x20
FALL—IQCLK invert. Default 0.
0 = Output data changes concurrently with the falling edge of IQCLK.
1 = Output data changes concurrently with the rising edge of IQCLK.
Default: 0x0
0x0 = I2S ZIF format (Default).
0x8 = Left-justified ZIF format.
0x9 = Right-justified ZIF format.
0xE = DSP ZIF format .
0xF = DSP Left-justified ZIF format.
Always write 1.
Rev. 0.3
53
AN645
9.2. Commands and Properties for FM Receiver
Table 14. FM Receiver Command Summary
Number
Name
Summary
0x30
FM_TUNE_FREQ
Tunes the FM receiver to a frequency in 10 kHz steps.
0x31
FM_SEEK_START
Initiates a seek for a channel that meets the validation criteria for
FM.
0x32
FM_RSQ_STATUS
Returns status information about the received signal quality.
0x35
FM_ACF_STATUS
Returns status information about automatically-controlled features
for the tuned station.
0x36
FM_RDS_STATUS
Returns RDS information for current channel and reads an entry
from the RDS FIFO.
0x37
FM_RDS_BLOCKCOUNT
Returns RDS expected, received, and uncorrectable block statistic
information.
Table 15. FM Receiver Property Summary
Number
Name
0x0302
AUDIO_DE_EMPHASIS
Default
Summary
0x0000
Sets the FM Receive de-emphasis.
0
0x0008
0x0400
FM_SOFT_MUTE_MAX_ATTENUATION
Sets the maximum soft mute attenuation.
8
0x0401
0x0008
FM_SOFT_MUTE_TRIGGER_
THRESHOLD
Sets the SNR threshold for soft mute to start.
8
0x0000
0x0402
FM_SOFT_MUTE_END_THRESHOLD
0
0x01F4
0x0403
FM_SOFT_MUTE_RELEASE_TIME
500
Sets the SNR threshold where soft mute will
stop attenuating.
Sets the maximum soft mute release time in
ms.
0x0078
0x0404
FM_SOFT_MUTE_ATTACK_TIME
Sets the maximum soft mute attack time in ms.
120
0x0000
0x0700
FM_AGC_FE_CONFIG
0
54
Rev. 0.3
Specified the input path for RF signal and other
FE configuration options.
AN645
Table 15. FM Receiver Property Summary (Continued)
Number
Name
0x0701
FM_AGC_PD_CONFIG
Default
0x0270
624
Summary
Specifies the behavior of the FM peak detectors and attenuators.
FM_LNA_AGC_ATTACK_MS
0x0004 Sets the number of milliseconds the wideband
RF
high-peak detector must be exceeded before
4
attenuating the appropriate block.
0x0703
FM_LNA_AGC_RELEASE_MS
0x0050 Sets the number of milliseconds the wideband
RF low-peak detector must not be exceeded
before increasing the gain of the appropriate
80
block.
0x0704
FM_LNA_AGC_PD_THRESHOLD
0x0702
0x4F05
20229
Sets the high threshold and hysteresis for the
LNA peak detector.
FM_MIXER_AGC_ATTACK_MS
0x0004 Sets the number of milliseconds the wideband
mixer high-peak detector must be exceeded
before attenuating the appropriate block.
4
0x0706
FM_MIXER_AGC_RELEASE_MS
0x0050 Sets the number of milliseconds the wideband
mixer low-peak detector must not be exceeded
before increasing the gain of the appropriate
80
block.
0x0707
FM_MIXER_AGC_PD_THRESHOLD
0x0705
0x5503
21763
0x0000
0x0710
FM_AGC_OVERRIDE
0
Sets the high threshold and hysteresis for the
mixer peak detector.
Overrides the AGC setting by disabling the
AGC and forcing the gain to be maximum.
0x1100
FM_SEEK_BAND_BOTTOM
0x222E Sets the lower seek boundary of the FM band
8750 in multiples of 10 kHz.
0x1101
FM_SEEK_BAND_TOP
0x2A26 Sets the upper seek boundary for the FM band
10790 in multiples of 10 kHz.
0x1102
FM_SEEK_FREQUENCY_SPACING
0x000A Sets the frequency spacing for the FM band in
multiples of 10 kHz when performing a seek.
10
0x1200
FM_RSQ_INTERRUPT_SOURCE
0x0000 Configures interrupt related to Received Signal
Quality metrics (FM_RSQ_STATUS).
0
0x1201
FM_RSQ_SNR_HIGH_THRESHOLD
0x007F Sets high threshold which triggers the RSQ
interrupt if the SNR is above this threshold.
127
0x1202
FM_RSQ_SNR_LOW_THRESHOLD
0xFF80 Sets low threshold which triggers the RSQ
–128 interrupt if the SNR is below this threshold.
Rev. 0.3
55
AN645
Table 15. FM Receiver Property Summary (Continued)
Number
Name
0x1203
FM_RSQ_RSSI_HIGH_THRESHOLD
0x007F Sets high threshold which triggers the RSQ
interrupt if the RSSI is above this threshold.
127
0x1204
FM_RSQ_RSSI_LOW_THRESHOLD
0xFF80 Sets low threshold which triggers the RSQ
–128 interrupt if the RSSI is below this threshold.
0x1207
FM_RSQ_MULTIPATH_HIGH_
THRESHOLD
0x007F Sets high threshold which triggers the RSQ
interrupt if Multipath is above this threshold.
127
0x1208
FM_RSQ_MULTIPATH_LOW_
THRESHOLD
0x0000 Sets low threshold which triggers the RSQ
interrupt if Multipath is below this threshold.
0
0x1300
FM_ACF_INTERRUPT_SOURCE
0x1301
FM_ACF_SM_THRESHOLD
0x1302
FM_ACF_CHBW_THRESHOLD
0x0000 Sets the Channel Filter Bandwidth interrupt
threshold in units of kHz.
0
0x1303
FM_ACF_HICUT_THRESHOLD
0x0000 Sets the Hi-cut interrupt threshold in units of
100 Hz.
0
0x1304
FM_ACF_HIBLEND_THRESHOLD
0x1305
FM_ACF_BLEND_THRESHOLD
0x1306
FM_ACF_CONTROL_SOURCE
0x2000
FM_VALID_MAX_TUNE_ERROR
0x2001
FM_VALID_RSSI_TIME
0x0006 Sets the amount of time in milliseconds to
allow the RSSI metric to settle before evaluat6
ing.
0x2002
FM_VALID_SNR_TIME
0x0012 Sets the amount of time in milliseconds to
allow the SNR metric to settle before evaluat18
ing.
0x2003
FM_VALID_SNR_THRESHOLD
0x0008 Sets the SNR threshold for a valid FM Seek/
Tune.
8
0x2004
FM_VALID_RSSI_THRESHOLD
0x000C Sets the RSSI threshold for a valid FM Seek/
Tune.
12
0x200A
FM_VALID_ASSI_THRESHOLD
0x503C Sets the ASSI/ASSI200 threshold for a valid
20540 FM Seek/Tune.
56
Default
0x0000
0
0x001F
31
Summary
Enables the ACF interrupt sources.
Sets the softmute interrupt threshold in dB.
0x0000 Sets the Hi-blend interrupt threshold in units of
100 Hz.
0
0x0000 Sets the Stereo Blend interrupt threshold in
units of % L-R gain.
0
0x0001
1
Sets the controlling metric for ACF features.
0x004B Sets the maximum frequency error in 2 ppm
allowed before setting the AFCRL indicator.
75
Rev. 0.3
AN645
Table 15. FM Receiver Property Summary (Continued)
Number
Name
Default
Summary
0x2200
FM_CHBW_RSSI_MIN_MAX
0x2201
FM_CHBW_SQ_HIGH_THRESHOLD
0x000C Sets the RSSI/DEV threshold for maximum
channel filter bandwidth.
12
0x2202
FM_CHBW_SQ_LOW_THRESHOLD
0xFFFC Sets the RSSI/DEV threshold for minimum
channel filter bandwidth.
–4
0x2203
FM_CHBW_SQ_WIDENING_TIME
0x2204
FM_CHBW_SQ_NARROWING_TIME
0x2205
FM_CHBW_ASSI_MIN_MAX
0x9623 Sets the 100 kHz blocker delta (difference
between HASSI and LASSI) for maximum and
38435 minimum channel BW in units of kHz.
0x2206
FM_CHBW_ASSI_LOW_THRESHOLD
0x0007 Sets the 100kHz blocker delta (difference
between HASSI and LASSI) threshold for max7
imum channel filter bandwidth.
0x2207
FM_CHBW_ASSI_HIGH_THRESHOLD
0x0014 Sets the 100kHz blocker delta (difference
between HASSI and LASSI) threshold for mini20
mum channel filter bandwidth.
0x2208
FM_CHBW_ASSI_WIDENING_TIME
0x0C80 Sets the channel filter bandwidth widening time
based on the 100 kHz blocker delta (difference
3200 between HASSI and LASSI).
0x2209
FM_CHBW_ASSI_NARROWING_TIME
0x0140 Sets the channel filter bandwidth narrowing
time based on the 100 kHz blocker delta (dif320
ference between HASSI and LASSI).
0x220A
FM_CHBW_ASSI200_MIN_MAX
0x9650 Sets the 200 kHz blocker strength maximum
38480 and minimum channel BW in units of kHz.
0x220B
FM_CHBW_ASSI200_LOW_THRESHOLD
0xFFF6 Sets the 200 kHz blocker strength threshold for
maximum channel filter bandwidth.
–10
0x220C
FM_CHBW_ASSI200_HIGH_THRESHOLD
0x000A Sets the 200 kHz blocker strength threshold for
minimum channel filter bandwidth.
10
0x220D
FM_CHBW_ASSI200_WIDENING_TIME
0x0C80 Sets the channel filter bandwidth widening time
3200 based on 200 kHz blocker strength.
0x220E
FM_CHBW_ASSI200_NARROWING_
TIME
0x220F
FM_CHBW_WEAKSIG_THR
0x9637 Sets the maximum and minimum channel BW
38455 in units of kHz based on RSSI/DEV.
0x0010 Sets the channel filter bandwidth widening time
based on RSSI/DEV.
16
0x0800 Sets the channel filter bandwidth narrowing
2048 time based on RSSI/DEV.
0x140
320
Sets the channel filter bandwidth narrowing
time based on 200 kHz blocker strength.
0x100D Sets the hysteresis window for the weak signal
4109 channel filter bandwidth engine.
Rev. 0.3
57
AN645
Table 15. FM Receiver Property Summary (Continued)
Number
Name
0x2210
FM_CHBW_BLOCKER_THR
0x3105
FM_LOWCUT_MIN_FREQ
0x3106
FM_LOWCUT_MAX_FREQ
0x3300
FM_IBOC_CONTROL
0x3301
FM_IBOC_ANALOG_TO_HD_
CROSSFADE_TIME
0x03E8 Sets the crossfade time between full analog
1000 and full HD Digital audio in ms. (Si4777 only).
0x3302
FM_IBOC_HD_TO_ANALOG_
CROSSFADE_TIME
0x03E8 Sets the crossfade time from full HD Digital
1000 audio to full analog audio in ms. (Si4777 only).
0x3303
FM_IBOC_DYNAMIC_GAIN
0x007F Sets the digital audio dynamic linear scaling
factor. (Si4777 only).
127
0x3304
FM_IBOC_STATIC_GAIN
0x0100 Sets the digital audio static linear gain factor.
(Si4777 only).
256
0x3400
FM_MULT_EQ_CTL
0x3401
FM_MULT_EQ_NOISE_DISABLE
0xFC81 Sets the RSSI threshold below which the channel equalizer will use noise measurements to
64641 enable/disable the channel equalizer.
0x3500
FM_BLEND_RSSI_THRESHOLDS
0x3719 Sets the thresholds for the RSSI metric for the
14105 stereo blend mitigation engine.
0x3501
FM_BLEND_RSSI_STEREO_SEP
0x2D00 Set the limits for the stereo separation when
driven by RSSI on the stereo blend mitigation
11520 engine.
0x3502
FM_BLEND_RSSI_ATTACK_TIME
0x3503
FM_BLEND_RSSI_RELEASE_TIME
0x3508
FM_BLEND_MULTIPATH_
THRESHOLDS
0x1E3C Sets the thresholds for the multipath metric for
7740 the stereo blend mitigation engine.
0x3509
FM_BLEND_MULTIPATH_
STEREO_SEP
0x2D00 Sets the limits for the stereo separation when
driven by multipath on the stereo blend mitiga11520 tion engine.
58
Default
0x140A
5130
0x0000
0
0x0000
0
0x0000
0
0x1401
5121
0x0010
16
0x0FA0
4000
Rev. 0.3
Summary
200 kHz stereo blocker threshold control
Sets the minimum LowCut cutoff frequency
Sets the maximum LowCut cutoff frequency
Control property for IBOC Blend (Si4777 only).
Controls the multipath channel equalizer.
Sets the stereo blend attack time in ms.
Sets the stereo blend release time in ms.
AN645
Table 15. FM Receiver Property Summary (Continued)
Number
Name
Default
0x350A
FM_BLEND_MULTIPATH_ATTACK_TIME
0x350B
FM_BLEND_MULTIPATH_
RELEASE_TIME
0x3510
FM_BLEND_USN_THRESHOLDS
0x341B Set the thresholds for the USN metric for the
13339 stereo blend mitigation engine.
0x3511
FM_BLEND_USN_STEREO_SEP
0x2D00 Sets the limits for the stereo separation when
driven by USN on the stereo blend mitigation
11520 engine.
0x3512
FM_BLEND_USN_ATTACK_TIME
0x3513
FM_BLEND_USN_RELEASE_TIME
0x3600
FM_HICUT_RSSI_THRESHOLDS
0x230F Sets the thresholds for the RSSI metric for the
8975 high cut mitigation engine.
0x3601
FM_HICUT_RSSI_CUTOFF_FREQ
0xB428 Sets the limits for the cutoff frequency when
driven by RSSI on the high cut mitigation
46120 engine.
0x3602
FM_HICUT_RSSI_ATTACK_TIME
0x3603
FM_HICUT_RSSI_RELEASE_TIME
0x3608
FM_HICUT_ MULTIPATH_THRESHOLDS
0x3250 Sets the thresholds for the multipath metric for
12880 the high cut mitigation engine.
0x3609
FM_HICUT_ MULTIPATH_CUTOFF_FREQ
0xB428 Set the limits for the cutoff frequency when
driven by multipath on the high cut mitigation
46120 engine.
0x360A
FM_HICUT_ MULTIPATH_ATTACK_TIME
0x360B
FM_HICUT_ MULTIPATH_RELEASE_TIME
0x3610
FM_HICUT_ USN_THRESHOLDS
0x0010
16
0x0FA0
4000
0x0010
16
0x0FA0
4000
0x0010
16
0x0FA0
4000
0x0010
16
0xFA0
4000
Summary
Sets the stereo blend attack time in ms.
Sets the stereo blend release time in ms.
Sets the stereo blend attack time in ms.
Sets the stereo blend release time in ms.
Sets the high cut attack time in ms.
Sets the high cut release time in ms.
Sets the high cut attack time in ms.
Sets the high cut release time in ms.
0x250F Sets the thresholds for the USN metric for the
9487 high cut mitigation engine.
Rev. 0.3
59
AN645
Table 15. FM Receiver Property Summary (Continued)
Number
Name
0x3611
FM_HICUT_ USN_CUTOFF_FREQ
0x3612
FM_HICUT_USN_ATTACK_TIME
0x3613
FM_HICUT_USN_RELEASE_TIME
0x3700
FM_HIBLEND_RSSI_THRESHOLDS
0x371B Sets the thresholds for the RSSI metric for the
14107 high blend mitigation engine.
0x3701
FM_HIBLEND_RSSI_CUTOFF_FREQ
0xB41E Sets the limits for the cutoff frequency when
driven by RSSI on the high blend mitigation
46110 engine.
0x3702
FM_HIBLEND_RSSI_ATTACK_TIME
0x3703
FM_HIBLEND_RSSI_RELEASE_TIME
0x3708
FM_HIBLEND_MULTIPATH_
THRESHOLDS
0x193C Sets the thresholds for the multipath metric for
6460 the high blend mitigation engine.
0x3709
FM_HIBLEND_MULTIPATH_
CUTOFF_FREQ
0xB41E Sets the limits for the cutoff frequency when
driven by multipath on the Hi-blend mitigation
46110 engine.
0x370A
FM_HIBLEND_MULTIPATH_
ATTACK_TIME
0x0004
0x370B
FM_HIBLEND_MULTIPATH_
RELEASE_TIME
0x1F40
0x3710
FM_HIBLEND_USN_
THRESHOLDS
0x3711
FM_HIBLEND_USN_CUTOFF_FREQ
0x3712
FM_HIBLEND_USN_ATTACK_TIME
0x3713
FM_HIBLEND_USN_RELEASE_TIME
0x4000
FM_RDS_INTERRUPT_SOURCE
60
Default
Summary
0xB428 Sets the limits for the cutoff frequency when
driven by USN on the high cut mitigation
46120 engine.
0x0010
16
0x0FA0
4000
0x0004
4
0x1F40
8000
4
8000
Sets the high cut attack time in ms.
Sets the high cut release time in ms.
Sets the high blend attack time in ms.
Sets the high blend cut release time in ms.
Sets the high blend attack time in ms.
Sets the high blend release time in ms.
0x371E Sets the thresholds for the USN metric for the
14110 high blend mitigation engine.
0xB41E Sets the limits for the cutoff frequency when
driven by USN on the high blend mitigation
46110 engine.
0x0004
4
0x1F40
8000
0x0000
0
Rev. 0.3
Sets the high blend attack time in ms.
Sets the high blend release time in ms.
Configures interrupt related to RDS.
AN645
Table 15. FM Receiver Property Summary (Continued)
Number
Name
Default
Summary
0x4001
FM_RDS_INTERRUPT_FIFO_COUNT
0x0000 Sets the minimum number of RDS groups
stored in the RDS FIFO before RDSRECV is
0
set.
0x4002
FM_RDS_CONFIG
0x0000 Configures RDS settings to enable RDS processing (RDSEN) and set RDS block error
0
thresholds.
0x4003
FM_RDS_CONFIDENCE
0x1111 Sets the confidence level requirement for each
4369 RDS block.
Rev. 0.3
61
AN645
9.2.1. FM Receiver Commands
Command 0x30 FM_TUNE_FREQ
The FM_TUNE_FREQ command sets the FM Receiver to tune to a frequency between 64 and 108 MHz in 10 kHz
units. The CTS bit (and optional interrupt) is set when it is safe to send the next command. The ERR bit (and
optional interrupt) is set if an invalid argument is sent. Note that only a single interrupt occurs if both the CTS and
ERR bits are set. The optional STC interrupt is set when the command completes. This command may only be sent
in powerup mode. The command clears the STC bit if it is already set.
Command
Bit
7
6
5
4
3
0
HD
TUNEMODE[1:0]
0
ARG2
FREQH[7:0]
ARG3
FREQL[7:0]
ARG
Bit
Name
1
7
Reserved
1
6
HD
0
SMOOTHMETRICS
0
Function
Always write 0.
Places the part in the HD mode.
0 = Normal Bandwidth.
1 = Wide-Bandwidth/HD Mode.
Sets the desired tuning mode.
0 = Validated normal tune: Unconditionally stay on the
new channel after tune, tune status is valid.
1 = Invalidated fast tune: Unconditionally stay on the new
channel after tune, tune status invalid.
1
5:4
TUNEMODE[1:0]
1
3
Reserved
Always write 0.
1
2
SMOOTHMETRICS
Smoothly transition audio state after tune.
0 = Initialize audio state to match this new channel.
1 = Transition audio state from previous channel values to
the new channel values.
1
1:0
Reserved
Always write 0.
2
3
62
1
0x30
CMD
ARG1
2
7:0
7:0
FREQH[7:0]
Tune Frequency High Byte.
This byte in combination with FREQL selects the tune
frequency in units of 10 kHz. In FM mode the valid range is
from 6400 to 10800 (64–108 MHz).
FREQL[7:0]
Tune Frequency Low Byte.
This byte in combination with FREQH selects the tune
frequency in units of 10 kHz. In FM mode, the valid range is
from 6400 to 10800 (64–108 MHz).
Rev. 0.3
AN645
Response
Bit
7
6
STATUS
CTS
ERR
5
4
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
Command 0x31 FM_SEEK_START
The FM_SEEK_START command begins searching for a valid station. In order for a station to be considered valid,
each of the following thresholds must be met: FM_VALID_SNR_THRESHOLD and FM_VALID_RSSI_THRESHOLD and
FM_VALID_MAX_TUNE_ERROR. Clears any pending STCINT, RSQINT, or RDSINT interrupt status. Seek can be
cancelled through setting the CANCEL bit in the FM_RSQ_STATUS command. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. The ERR bit (and optional interrupt) is set if an invalid
argument is sent. Note that only a single interrupt occurs if both the CTS and ERR bits are set. The optional STC
interrupt is set when the command completes. This command may only be sent in powerup mode. The command
clears the STCINT bit if it is already set.
Command
Bit
7
6
5
4
3
2
SEEKUP
WRAP
1
0
0x31
CMD
0000
ARG1
00
ARG
Bit
Name
Function
1
7:4
Reserved
Always write 0.
1
3
SEEKUP
Seek Up/Down.
Determines the direction of the search, either UP = 1, or
DOWN = 0.
1
2
WRAP
1
1:0
Reserved
Wrap/Halt.
Determines whether the seek should Wrap = 1, or Halt = 0 when
it hits the band limit.
Always write 0.
Response
Bit
7
6
STATUS
CTS
ERR
5
4
XX
Rev. 0.3
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
63
AN645
Command 0x32 FM_RSQ_STATUS
The FM_RSQ_STATUS command returns status information about the received signal quality. This command
returns the Received Signal Strength Indicator (RSSI), Signal to Noise Ratio (SNR), Adjacent Channel Strength for
200 kHz (ASSI), Adjacent Channel Strength for 100 kHz (LASSI and HASSI), frequency offset (FREQOFF),
Multipath (MULT) and Ultrasonic Noise (USN) associated with the desired channel. It also indicates valid channel
(VALID) and AFC rail status (AFCRL). This command can be used to check if the received signal is above the
RSSI high threshold as reported by RSSIHINT or below the RSSI low threshold as reported by RSSILINT. It can
also be used to check if the signal is above the SNR high threshold as reported by SNRHINT or below the SNR low
threshold as reported by SNRLINT. It can be used to check if the detected multipath is above the Multipath high
threshold as reported by MULTHINT or below the Multipath low threshold as reported by MULTLINT.
The command clears the RSQINT, BLENDINT, SNRHINT, SNRLINT, RSSIHINT, RSSILINT, MULTHINT, and
MULTLINT interrupt bits when the RSQACK bit of ARG1 is set. If the condition is still true after the interrupt is
cleared, another interrupt will fire assuming that bit is enabled in FM_RSQ_INTERRUPT_SOURCE. The CTS bit
(and optional interrupt) is set when it is safe to send the next command. This command may only be sent when in
powerup mode.
FM_RSQ_
STATUS
Command
7
6
5
4
2
1
0
RSQACK
ATTUNE
CANCEL
STCACK
0x32
CMD
000
ARG1
64
3
0
ARG
Bit
Name
Function
1
7:5
Reserved
Always write 0.
1
4
Reserved
Always write 0.
1
3
RSQACK
Clears RSQINT, SNRHINT, SNRLINT, RSSIHINT, RSSILINT,
BLENDINT, MULTHINT, and MULTLINT if set.
1
2
ATTUNE
Returns the values of metrics as of tune time. When the
AT_TUNE bit is set, values returned for RSQ_STATUS are the
values calculated at tune and do not change unless another
FM_TUNE_FREQ command is called. This feature can be used
to determine why seek stopped at the current station.
1
1
CANCEL
Aborts a seek or tune currently in progress.
0 = Don't abort.
1 = Abort.
1
0
STCACK
Clears the STC interrupt status indicator if set.
Rev. 0.3
AN645
Response
Bit
7
6
STATUS
CTS
ERR
RESP1
RESP 2
MULTHINT MULTLINT
BLTF
X
5
4
XX
X
X
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
SNRHINT SNRLINT RSSIHINT RSSILINT
SNRREADY RSSIREADY
X
RESP 3
READFREQ[15:8]
RESP 4
READFREQ[7:0]
RESP 5
FREQOFF[7:0]
RESP 6
RSSI[7:0]
RESP 7
SNR[7:0]
RESP 8
XXXXXXXX
RESP 9
LASSI[7:0]
RESP 10
HASSI[7:0]
RESP 11
MULT[7:0]
RESP 12
DEV[7:0]
RESP 13
XX
RESP 14
XX
RESP 15
ASSI200[7:0]
RESP 16
USN[7:0]
RESP 17
PILOTDEV[7:0]
RESP 18
RDSDEV[7:0]
RESP 19
ASSI200DEV[7:0]
RESP 20
STRONGDEV[7:0]
RESP 21
RDSPI[15:8]
RESP 22
RDSPI[7:0]
Rev. 0.3
X
AFCRL
VALID
65
AN645
RESP
Bit
Name
1
7
MULTHINT
Function
Multipath Detect High.
0 = Indicates that multipath value has not exceeded
the Multipath high threshold set by
FM_RSQ_MULTIPATH_HIGH_THRESHOLD.
1 = Indicates that multipath value has exceeded the
Multipath high threshold set by
FM_RSQ_MULTIPATH_HIGH_THRESHOLD.
1
6
MULTLINT
Multipath Detect Low.
0 = Indicates that multipath value has not fallen below
the Multipath low threshold set by
FM_RSQ_MULTIPATH_LOW_THRESHOLD.
1 = Indicates that multipath value has fallen below the
Multipath low threshold set by
FM_RSQ_MULTIPATH_LOW_THRESHOLD.
1
5:4
Reserved
Values may vary.
1
3
SNRHINT
SNR Detect High.
0 = Indicates that the received signal SNR has not
exceeded the SNR high threshold set by
FM_RSQ_SNR_HIGH_THRESHOLD
1 = Indicates that the received signal SNR has
exceeded the SNR high threshold set by
FM_RSQ_SNR_HIGH_THRESHOLD.
1
2
SNRLINT
SNR Detect Low.
0 = Indicates that the received signal SNR has not
fallen below the SNR low threshold set by
FM_RSQ_SNR_LOW_THRESHOLD.
1 = Indicates that the received signal SNR has fallen
below the SNR low threshold set by
FM_RSQ_SNR_LOW_THRESHOLD.
1
1
RSSIHINT
RSSI Detect High.
0 = Indicates that the received signal RSSI has not
exceeded the RSSI high threshold set by
FM_RSQ_RSSI_HIGH_THRESHOLD.
1 = Indicates that the received signal RSSI has
exceeded the RSSI high threshold set by
FM_RSQ_RSSI_HIGH_THRESHOLD.
1
0
RSSILINT
RSSI Detect Low.
0 = Indicates that the received signal RSSI has not
fallen below the RSSI low threshold set by
FM_RSQ_RSSI_LOW_THRESHOLD.
1 = Indicates that the received signal RSSI has fallen
below the RSSI low threshold set by
FM_RSQ_RSSI_LOW_THRESHOLD.
66
Rev. 0.3
AN645
RESP
Bit
Name
Function
2
7
BLTF
2
6
Reserved
2
5
SNR READY
The SNRREADY and RSSIREADY bits indicate that
the RSSI/SNR have been read as a result of a tune
command. If either one of these bits are 0 this indicates
that either the metric is being measured (because a
tune is in progress) or that the metric was not measured during tune because the station was invalidated
before the metric could be measured. In the case
where a metric was not measured during tune, the tune
time RSQ status will read back as 0 for the unmeasured metric. The normal running time status for these
metrics is not affected and will report normally.
0 = SNR measurement in progress (tune in progress)
or not taken (tune completed).
1 = SNR measurement ready.
2
4
RSSIREADY
The SNRREADY and RSSIREADY bits indicate that
the RSSI/SNR have been read as a result of a tune
command. If either one of these bits are 0 this indicates
that either the metric is being measured (because a
tune is in progress) or that the metric was not measured during tune because the station was invalidated
before the metric could be measured. In the case
where a metric was not measured during tune, the tune
time RSQ status will read back as 0 for the unmeasured metric. The normal running time status for these
metrics is not affected and will report normally.
0 = RSSI measurement in progress (tune in progress)
or not taken (tune completed).
1 = RSSI measurement ready.
2
3:2
Reserved
2
1
AFCRL
Set if the AFC rails. AFC gets railed if FREQOFF >
MAX_TUNE_ERROR.
2
0
VALID
Reports if the channel is valid based on the settings of
FM_VALID_RSSI_THRESHOLD, FM_VALID_SNR_THRESHOLD, FM_VALID_MAX_TUNE_ERROR
3,4
15:0
READFREQ[15:0]
5
7:0
FREQOFF[7:0]
6
7:0
RSSI[7:0]
Received Signal Strength indicator in dBµV
(–128 to 127)
7
7:0
SNR[7:0]
RF SNR indicator in dB (–128 to 127).
8
7:0
Reserved
Values may vary.
Band Limit.
Reports if a seek hits the band limit (WRAP = 0 in
FM_START_SEEK) or wrapped to the original frequency (WRAP = 1).
Values may vary.
Values may vary.
Returns the currently tuned frequency.
Signed frequency offset in units of 2 ppm
(–128 to 127)
Rev. 0.3
67
AN645
RESP
Bit
Name
Function
9
7:0
LASSI[7:0]
Low side Adjacent (100 kHz) Channel Strength Indicator reports the (Signal + Noise) power relative to the
carrier.(–128 to 127)
10
7:0
HASSI[7:0]
High side Adjacent (100 kHz) Channel Strength Indicator reports the (Signal + Noise) power relative to the
carrier.(–128 to 127)
11
7:0
MULT[7:0]
Multipath indicator (0–127%).
12
7:0
DEV[7:0]
Frequency Deviation metric in kHz.
13, 14
15:0
Reserved
Values may vary.
15
7:0
ASSI200[7:0]
16
7:0
USN[7:0]
17
7:0
PILOTDEV[7:0]
Pilot deviation in units of 100 Hz.
18
7:0
RDSDEV[7:0]
RDS deviation in units of 100 Hz.
19
7:0
ASSI200DEV[7:0]
Adjacent Channel (±200 kHz) Deviation in units of
1.45 kHz.
20
7:0
STRONGDEV[7:0]
Deviation of strong desired signals. This is an alternative to DEV, which can become erroneous in the presence of very strong signals.
Approximately, deviation in kHz = STRONGDEV x
f(mod), where f(mod) is 5.55 kHz for mono signals or
2.75 kHz for stereo signals
21, 22
68
15:0
RDSPI[15:0]
Adjacent Channel (±200 kHz) Strength Indicator
reports the (Signal + Noise) power relative to the carrier. This metric reports the sum of high and low adjacent channel strengths. (–128 to 127)
Ultrasonic Noise Indicator in –dBFS (0 to 127). 127
corresponds to 127 dB down from full scale.
RDS PI code.
Rev. 0.3
AN645
Command 0x35 FM_ACF_STATUS
The FM_ACF_STATUS command returns status information about automatically-controlled features. This
command returns the Soft Mute Attenuation, Channel Filter Bandwidth, Hi-cut cutoff frequency, Hi-blend cutoff
frequency, and Stereo Separation associated with the desired channel. Stereo Separation will only be non-zero if
the pilot indicator is set. If SMUTE bit is high, it indicates that audio is soft-muted. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode.
Command
Bit
7
6
5
4
CMD
3
2
1
0
0x35
ARG1
0000000
ACFACK
ARG
Bit
Name
Function
1
7:1
Reserved
Always write 0.
1
0
ACFACK
If set clears ACFINT and any ACF interrupts bits.
Response
Bit
7
6
STATUS
CTS
ERR
XXX
RESP1
5
4
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
BLEND_INT HIBLEND_INT
HICUT_INT
XXXXXXX
RESP2
SMUTE
XXX
RESP3
SMATTN[4:0]
RESP4
CHANBW[7:0]
RESP5
HICUT[7:0]
RESP6
HIBLEND[7:0]
RESP7
RESP8
PILOT
CHBW_INT SOFTMUTE_INT
STBLEND[6:0]
LOWCUT[7:0]
Rev. 0.3
69
AN645
70
RESP
Bit
Name
Function
1
7:5
Reserved
1
4
BLEND_INT
If set, indicates that stereo separation has crossed below the
blend threshold set by FM_ACF_BLEND_THRESHOLD.
1
3
HIBLEND_INT
If set, indicates that the HiBlend cutoff frequency is lower than
the threshold as set by FM_ACF_HIBLEND_THRESHOLD.
1
2
HICUT_INT
If set, indicates that the HiCut cutoff frequency is lower than the
threshold set by FM_ACF_HICUT_THRESHOLD.
1
1
CHBW_INT
If set, indicates that the Channel Filter Bandwidth is less than
the threshold set by ACF_CHBW_THRESHOLD.
1
0
SOFTMUTE_INT
If set, indicates that softmute attenuation has increased above
the softmute threshold as set by ACF_SM_THRESHOLD.
2
7:1
Reserved
2
0
SMUTE
3
7:0
SMATTN[7:0]
Soft mute attenuation level in dB.
Range: 0–31.
4
7:0
CHANBW[7:0]
Channel filter bandwidth in kHz.
Range: 0–150.
5
7:0
HICUT[7:0]
6
7:0
HIBLEND[7:0]
7
7
PILOT
7
6:0
STBLEND[6:0]
Indicates stereo separation. STBLEND will only be non-zero if
PILOT = 1. Range 0–100.
7
7:0
LOWCUT[7:0]
Lowcut cutoff frequency in units of 10 Hz. Range 1–100.
Values may vary.
Values may vary.
0 = Audio is not soft muted.
1 = Audio is soft muted.
HiCut cutoff frequency in units of 100 Hz.
Range: 10–180.
HiBlend cutoff frequency in units of 100 Hz.
Range: 10–180.
0 = Stereo pilot is not present.
1 = Stereo pilot is present.
Rev. 0.3
AN645
Command 0x36 FM_RDS_STATUS
The FM_RDS_STATUS command returns RDS information for current channel and reads an entry from the RDS
FIFO. RDS information includes synch status, FIFO status, group data (blocks A, B, C, and D), and block errors
corrected. Maximum RDS FIFO size is 25 groups. This command clears the RDSINT interrupt bit when INTACK bit
in ARG1 is set, and, if MTFIFO is set, the entire RDS receive FIFO is cleared (FIFO is always cleared during
FM_TUNE_FREQ or FM_SEEK_START). The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This command may only be sent in powerup mode.
Command
Bit
7
6
5
4
2
1
0
STATUS_ONL
Y
MTFIFO
INTACK
0x36
CMD
ARG1
00000
ARG
Bit
Name
1
7:3
Reserved
1
3
2
STATUS_ONLY
Function
Always write 0.
Status Only.
Determines if data should be removed from the RDS FIFO.
0 = Data is removed from RDS FIFO, and RDSFIFOUSED decrements by one. Data in BLOCKA, BLOCKB, BLOCKC, BLOCKD,
and BLE contain the oldest data in the RDS FIFO.
1 = Data is not removed from RDSFIFO, and the RDSFIFOUSED
value stays the same. Data in BLOCKA, BLOCKB, BLOCKC,
BLOCKD, BLE, PI, TP, PTY, and status contain the last valid data
received for the current station.
1
1
MTFIFO
Empty FIFO.
The FIFO will always be cleared during FM_TUNE_FREQ and
FM_SEEK_START.
0 = If FIFO not empty, read and remove oldest FIFO entry.
1 = Clear RDS Receive FIFO.
1
0
INTACK
Interrupt Acknowledge.
0 = RDSINT status preserved.
1 = Clears RDSINT.
Rev. 0.3
71
AN645
Response
Bit
7
6
STATUS
CTS
ERR
RESP1
XXX
RESP2
XXX
RESP3
XX
5
4
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
X
RDSSYNCINT
RDSFIFOINT
X
RDSSYNC
RDSFIFOLOST
RDSTPPTYINT RDSPIINT
TPPTYVALID
PIVALID
TP
PTY[4:0]
RESP4
PI[15:8]
RESP5
PI[7:0]
RESP6
RDSFIFOUSED[7:0]
RESP7
BLEA[1:0]
BLEB[1:0]
BLEC[1:0]
RESP8
BLOCKA[15:8]
RESP9
BLOCKA[7:0]
RESP10
BLOCKB[15:8]
RESP11
BLOCKB[7:0]
RESP12
BLOCKC[15:8]
RESP13
BLOCKC[7:0]
RESP14
BLOCKD[15:8]
RESP15
BLOCKD[7:0]
72
Rev. 0.3
BLED[1:0]
AN645
RESP
Bit
Name
1
7:5
Reserved
1
4
RDSTPPTYINT
1
3
RDSPIINT
1 = PI (Program Identification) code has changed.
1
2
Reserved
Values may vary.
1
1
RDSSYNCINT
1 = RDS synchronization has changed.
1
0
RDSFIFOINT
1 = RDS was received and the RDS FIFO is full or has atleast
FM_RDS_INTERRUPT_FIFO_COUNT entries.
2
7:5
Reserved
2
4
TPPTYVALID
2
3
PIVALID
1 = Indicates that PI code is valid.
2
2
Reserved
Values may vary.
2
1
RDSSYNC
2
0
RDSFIFOLOST
3
7:6
Reserved
3
5
TP
3
4:0
PTY[4:0]
Current channel's PTY code if TPPTYVALID is 1.
4,5
15:0
PI[15:0]
Current channel’s PI code if PIVALID is set to 1.
6
7
7
7
7:0
7:6
5:4
3:2
RDSFIFOUSED[7:0]
Function
Values may vary.
1 = TP (Traffic Program) flag and/or PTY (Program Type) code
has changed.
Values may vary.
1 = Indicates that TP flag and PTY code are valid.
1 = RDS is currently synchronized.
1 = Indicates that one or more RDS groups have been discarded
due to FIFO overrun since last call to FM_RDS_STATUS.
Values may vary.
Current channel’s TP flag if TPPTYVALID is set to 1.
RDS FIFO Used.
Number of groups remaining in the RDS FIFO (0 if empty). If
non-zero, BLOCKA-BLOCKD contain the oldest FIFO entry and
RDSFIFOUSED decrements by one on the next call to RDS_FIFO_STATUS (assuming no RDS data received in the interim).
BLEA[1:0]
RDS Block A Corrected Errors.
0 = No errors.
1 = 1–2 bit errors detected and corrected.
2 = 3–5 bit errors detected and corrected.
3 = Uncorrectable.
BLEB[1:0]
RDS Block B Corrected Errors.
0 = No errors.
1 = 1–2 bit errors detected and corrected.
2 = 3–5 bit errors detected and corrected.
3 = Uncorrectable.
BLEC[1:0]
RDS Block C Corrected Errors.
0 = No errors.
1 = 1–2 bit errors detected and corrected.
2 = 3–5 bit errors detected and corrected.
3 = Uncorrectable.
Rev. 0.3
73
AN645
RESP
74
Bit
Name
Function
RDS Block D Corrected Errors.
0 = No errors.
1 = 1–2 bit errors detected and corrected.
2 = 3–5 bit errors detected and corrected.
3 = Uncorrectable.
7
1:0
BLED[1:0]
8,9
15:0
BLOCKA[15:0]
Block A group data from oldest FIFO entry if STATUSONLY is 0.
Last valid Block A data if STATUSONLY is 1.
10,11
15:0
BLOCKB[15:0]
Block B group data from oldest FIFO entry if STATUSONLY is 0.
Last valid Block A data if STATUSONLY is 1.
12,13
15:0
BLOCKC[15:0]
Block C group data from oldest FIFO entry if STATUSONLY is 0.
Last valid Block A data if STATUSONLY is 1.
14,15
15:0
BLOCKC[15:0]
Block D group data from oldest FIFO entry if STATUSONLY is 0.
Last valid Block A data if STATUSONLY is 1.
Rev. 0.3
AN645
Command 0x37 FM_RDS_BLOCKCOUNT
The FM_RDS_BLOCKCOUNT command returns RDS expected, received, and uncorrectable block statistic
information. Reset info by setting CLEAR bit or sending FM_TUNE_FREQ or FM_SEEK_START commands. Once
EXPECTED saturates at 65535, all other block count statistics will be frozen until the counts are cleared. The CTS
bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent when
in powerup mode.
Command
Bit
7
6
5
4
3
2
1
0
0x37
CMD
0000000
ARG1
ARG
Bit
Name
1
7:1
Reserved
1
0
CLEAR
CLEAR
Function
Always write 0.
Clears the block counts if set. The current block counts will be
reported before they are cleared.
Response
Bit
7
6
STATUS
CTS
ERR
5
4
XX
3
2
1
0
RSQINT
RDSINT
ACFINT
STCINT
RESP1
XXXXXXXX
RESP 2
EXPECTED[15:8]
RESP 3
EXPECTED[7:0]
RESP 4
RECEIVED[15:8]
RESP 5
RECEIVED[7:0]
RESP 6
UNCORRECTABLE[15:8]
RESP 7
UNCORRECTABLE[7:0]
RESP
Bit
Name
1
7:0
Reserved
2,3
15:0
EXPECTED[15:0]
Number of expected RDS blocks.
4,5
15:0
RECEIVED[15:0]
Number of received RDS blocks. Under ideal conditions,
EXPECTED and RECEIVED would be identical. The difference
between these two numbers is the number of blocks lost.
6,7
15:0
Function
Values may vary.
Number of uncorrectable RDS blocks. These blocks have been
received, but were found to have uncorrectable errors. The block
UNCORRECTABLE[15:0]
error rate (BLER) is calculated by: BLER = (UNCORRECTABLE +
(EXPECTED-RECEIVED)) / EXPECTED
Rev. 0.3
75
AN645
9.2.2. FM Receiver Properties
Property 0x0302 AUDIO_DE_EMPHASIS
The AUDIO_DE_EMPHASIS property sets the FM Receive de-emphasis to 50 or 75 μs. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
The default is 75 μs.
Default: 0
AUDIO_DE_EMPHASIS
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0x0000
DE_EMPH
0x0000
0
Bit
Name
Function
15:1
Reserved
Always write 0.
0
DE_EMPH
Sets the FM Receive de-emphasis to 50 or 75 μs. Default is 75 µs.
0 = 75 µsec
1 = 50 µsec
Property 0x0400 FM_SOFT_MUTE_MAX_ATTENUATION
The FM_SOFT_MUTE_MAX_ATTENUATION property sets the maximum attenuation in dB that will be applied by
the softmute feature. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
property may only be set or read in powerup mode.
Default: 8
Units: dB
FM_SOFT_MUTE_MAX_ATTENUATION
15
76
14
13
12
11
10
9
8
7
6
5
4
3
2
0x000
SMATTN[6:0]
0x000
0x08
Bit
Name
15:5
Reserved
4:0
SMATTN[6:0]
1
0
Function
Always write 0.
Sets the maximum attenuation in dB that will be applied by the softmute
feature.
Default is 8 dB. Range is 0–63 dB.
Rev. 0.3
AN645
Property 0x0401 FM_SOFT_MUTE_TRIGGER_THRESHOLD
The FM_SOFT_MUTE_TRIGGER_THRESHOLD property sets the SNR threshold in dB to engage softmute. The
CTS bit (and optional interrupt) is set when it is safe to send the next command. If USE_RSSI is set in
FM_ACF_CONTROL_SOURCE property, then property 0x0401 refers to RSSI threshold. This property may only
be set or read in powerup mode.
Default: 8
Units: dB (dBµV if RSSI is used as the control source)
FM_SOFT_MUTE_TRIGGER_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
0x00
SMTRGTH[7:0]
0x00
0x08
Bit
Name
15:8
Reserved
7:0
SMTRGTH[7:0]
2
1
0
Function
Always write 0.
Sets the SNR threshold in dB to engage softmute.
Default is 8 dB. Range is –127 to 127 dB (dBµV if RSSI is used as the control source).
Property 0x0402 FM_SOFT_MUTE_END_THRESHOLD
The FM_SOFT_MUTE_END_THRESHOLD property sets the SNR threshold in dB at which softmute attenuation
will be set to its maximum value. When the SNR is at this level or lower, the audio attenuation will be set to
FM_SOFT_MUTE_MAX_ATTENUATION. The CTS bit (and optional interrupt) is set when it is safe to send the
next command. If USE_RSSI is set in the FM_ACF_CONTROL_SOURCE property, then property 0x0402 refers to
the RSSI threshold. This property may only be set or read in powerup mode.
Default: 0
Units: dB (dBµV if RSSI is used as the control source)
FM_SOFT_MUTE_END_THRESHOLD
15
14
13
12
10
9
8
7
6
5
4
3
0x00
SMENDTH[7:0]
0x00
0x00
Bit
Name
15:8
Reserved
7:0
11
SMENDTH[7:0]
2
1
0
Function
Always write 0.
Sets the SNR threshold in dB at which softmute attenuation will be set to its
maximum value given by FM_SOFT_MUTE_MAX_ATTENUATION property. Default is 0 dB. Range is –127 to 127 dB (dBµV if RSSI is used as the
control source).
Rev. 0.3
77
AN645
Property 0x0403 FM_SOFT_MUTE_RELEASE_TIME
The FM_SOFT_MUTE_RELEASE_TIME property sets the maximum time in ms it takes to unmute the audio. The
CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or
read in powerup mode.
Default: 500
Units: ms
FM_SOFT_MUTE_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x01F4
Bit
Name
15:0
Function
RELEASE[15:0]
Sets the maximum time in ms it takes to unmute the audio.
Default is 500 ms. Range is 1–32767 ms. Note that there will be 16 ms of
filter delay for the RSSI/SNR metric before softmute can engage/disengage.
Property 0x0404 FM_SOFT_MUTE_ATTACK_TIME
The FM_SOFT_MUTE_ATTACK_TIME property sets the maximum time in ms it takes to mute the audio. The CTS
bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 120
Units: ms
FM_SOFT_MUTE_ATTACK_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK[15:0]
0x0078
Bit
15:0
78
Name
ATTACK[15:0]
Function
Sets the maximum time in ms it takes to mute the audio.
Default is 120 ms. Range is 1–32767 ms. Note that there will be 16 ms of
filter delay for the RSSI/SNR metric before softmute can engage/disengage.
Rev. 0.3
AN645
Property 0x0700 FM_AGC_FE_CONFIG
The FM_AGC_FE_CONFIG property specifies the input path for the RF signal and other FE configuration options.
This property should only be set before the first tune. The CTS bit (and optional interrupt) is set when it is safe to
send the next command. This property may only be set or read in powerup mode. Changes to this property take
effect after the next tune is completed.
Default: 0
FM_AGC_FE_CONFIG
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0x00
FMLNAZ
FMMIX
0x0
Reserved
INPUTSELECT[3:0]
0x00
0
0
0x0
0
0x0
0
Bit
Name
Function
15:9
Reserved
Always write 0.
8
FMLNAZ
0 = Normal LNA mode where the LNA input impedance is 50 .
1 = LNA loopthru mode where LNA input impedance is 100 
7
FMMIX
6:4
Reserved
3:0
INPUTSELECT[3:0]
0 = Mixer is differential input (FMXIP/FMXIN)
1 = Mixer is single ended (FMXIP)
Always write 0.
0 = Received signal comes into FMI pin, out FMO and then the
mixer pin.
1 = Received signal comes directly into the mixer.
Rev. 0.3
79
AN645
Property 0x0701 FM_AGC_PD_CONFIG
The FM_AGC_PD_CONFIG property specifies behavior of the FM peak detectors and attenuators. This property
should only be set before the first tune. The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This command may only be sent in powerup mode. Changes to this property take effect after the next
tune is completed.
Default: 0x0270
FM_AGC_PD_CONFIG
15
14
12
11
10
9
8
7
6
5
4
3
2
1
0
0x0
LNA_MODE
00100
MIXER_PD[2:0]
0x00
LNA_PD[1:0]
0x0
0
00100
0x7
0x00
0x00
Bit
Name
15:13
Reserved
12
LNA_MODE
11:7
Reserved
6:4
MIXER_PD[2:0]
3:2
Reserved
1:0
80
13
LNA_PD[1:0]
Function
Always write 0.
LNA_MODE default: 0 This property only used when the LNA gain
and one or both of the attenuators are controlled by the same peak
detector.
0 = Reduce LNA gain and then attenuate.
1 = Attenuate and then reduce LNA gain.
Always write 00100.
MIXER_PD[2:0] default: 0x7.
0 = Peak detector not used.
1 = Controls FMAGC1.
2 = Controls FMAGC2.
3 = Controls FMAGC1 and FMAGC2.
4 = Controls LNA gain.
5 = Controls LNA gain and FMAGC1.
6 = Controls LNA gain and FMAGC2.
7 = Controls LNA gain, FMAGC1 and FMAGC2.
Always write 0.
LNA_PD[1:0] default: 0x0
0 = Peak detector not used
1 = Controls FMAGC1
2 = Controls FMAGC2
3 = Controls FMAGC1 and FMAGC2
Rev. 0.3
AN645
Property 0x0702 FM_LNA_AGC_ATTACK_MS
The FM_LNA_AGC_ATTACK_MS property sets the number of milliseconds the wide-band RF high-peak detector
must be exceeded before attenuating the appropriate block. The peak detectors are only sampled once every 3 to
5 ms. If the peak detector trips, the internal counter is incremented by 4 ms.The CTS bit (and optional interrupt) is
set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 4
Units: ms
FM_LNA_AGC_ATTACK_MS
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RF_AGC_ATTACK_MS[15:0]
0x04
Bit
15:0
Name
Function
RF_AGC_ATTACK_MS[15:0]
Number of milliseconds the wideband RF highpeak detector must be exceeded before attenuating the appropriate block.
Default is 4 ms.
Range is 4–4096 ms.
Property 0x0703 FM_LNA_AGC_RELEASE_MS
The FM_LNA_AGC_RELEASE_MS property sets the number of milliseconds the wideband RF low-peak detector
must not be exceeded before increasing the gain of the appropriate block. The peak detectors are only sampled
once every 3 to 5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 80
Units: ms
FM_LNA_AGC_RELEASE_MS
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RF_AGC_RELEASE_MS[15:0]
0x50
Bit
15:0
Name
Function
Number of milliseconds the wideband RF low-peak detector must not
be exceeded before increasing the gain of the appropriate block.
RF_AGC_RELEASE_MS[15:0]
Default is 80 ms
Range is 4–4096 ms.
Rev. 0.3
81
AN645
Property 0x0704 FM_LNA_AGC_PD_THRESHOLD
The FM_LNA_AGC_PD_THRESHOLD property sets the high threshold and hysteresis for the LNA peak detector.
The high threshold sets the level at which the AGC increases attenuation. The hysteresis is how many dB below
the high threshold the level must drop before the AGC decreases attenuation. It is possible to decrease the
likelihood of intermod break-in by decreasing the peak detector threshold from the default and it is possible to
decrease the likelihood of desensitization by increasing the peak detector threshold. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0x4F05
FM_LNA_AGC_PD_THRESHOLD
15
14
Bit
15:8
7:0
82
13
12
11
10
9
8
7
6
5
4
3
HIGH[7:0]
HYST[7:0]
0x4F
0x05
Name
2
1
0
Function
HIGH[7:0]
Sets the level in dBµV at which AGC increases attenuation
HIGH[7:0] Range: 73–87
73 = 73 dBµV
75 = 75 dBµV
77 = 77 dBµV
79 = 79 dBµV
81 = 81 dBµV
83 = 83 dBµV
85 = 85 dBµV
87 = 87 dBµV
HYST[7:0]
Sets how many dB below the high threshold the level must drop
before the AGC decreases attenuation.
HYST[7:0] Range: 3–6
3 = 3 dB
4 = 4 dB
5 = 5 dB
6 = 6 dB
Rev. 0.3
AN645
Property 0x0705 FM_MIXER_AGC_ATTACK_MS
The FM_MIXER_AGC_ATTACK_MS property sets the number of milliseconds the wideband mixer high-peak
detector must be exceeded before attenuating the appropriate block. The peak detectors are only sampled once
every 3–5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 4
Units: ms
FM_MIXER_AGC_ATTACK_MS
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
MIX_AGC_ATTACK_MS[15:0]
0x04
Bit
15:0
Name
Function
MIX_AGC_ATTACK_MS[15:0]
Number of milliseconds the wideband RF highpeak detector must be exceeded before attenuating the appropriate block.
Default is 4 ms
Range is 4–4096 ms.
Property 0x0706 FM_MIXER_AGC_RELEASE_MS
The FM_MIXER_AGC_RELEASE_MS property sets the number of milliseconds the wideband mixer low-peak
detector must not be exceeded before increasing the gain of the appropriate block. The peak detectors are only
sampled once every 3–5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit
(and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 80
Units: ms
FM_MIXER_AGC_RELEASE_MS
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
MIX_AGC_RELEASE_MS[15:0]
0x50
Bit
15:0
Name
Function
Number of milliseconds the wideband RF low-peak detector must not
be exceeded before increasing the gain of the appropriate block.
MIX_AGC_RELEASE_MS[15:0]
Default is 80 ms
Range is 4–4096 ms.
Rev. 0.3
83
AN645
Property 0x0707 FM_MIXER_AGC_PD_THRESHOLD
The FM_MIXER_AGC_PD_THRESHOLD property sets the high threshold and hysteresis for the mixer peak
detector. The high threshold sets the level at which the AGC increases attenuation. The hysteresis is how many dB
below the high threshold the level must drop before the AGC decreases attenuation. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0x5503
FM_MIXER_AGC_PD_THRESHOLD
15
14
Bit
15:8
7:0
84
13
12
11
10
9
8
7
6
5
4
3
HIGH[7:0]
HYST[7:0]
0x55
0x03
Name
2
1
0
Function
HIGH[7:0]
Sets the level in dBµV at which AGC increases attenuation.
HIGH[7:0]: Range 79–93.
79 = 79 dBµV.
81 = 81 dBµV.
83 = 83 dBµV.
85 = 85 dBµV.
87 = 87 dBµV.
89 = 89 dBµV.
91 = 91 dBµV.
93 = 93 dBµV.
HYST[7:0]
Sets how many dB below the high threshold the level must drop
before the AGC decreases attenuation.
HYST[7:0] - Range: 3–6.
3 = 3 dB.
4 = 4 dB.
5 = 5 dB.
6 = 6 dB.
Rev. 0.3
AN645
Property 0x0710 FM_AGC_OVERRIDE
The FM_AGC_OVERRIDE property overrides the AGC setting by disabling the AGC and forcing the gain to be
maximum. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may
only be set or read in powerup mode.
Default: 0x0000
FM_AGC_OVERRIDE
15
14
13
12
11
10
9
7
6
5
4
3
2
1
0x000
AGC_OVERRIDE[5:0]
0x000
0
Bit
Name
15:6
Reserved
5:0
8
0
Function
Always write 0.
AGC_OVERRIDE selects whether the AGC is
enabled or disabled.
0 = AGC is enabled.
0x3F = AGC is disabled and set to maximum
gain.
AGC_OVERRIDE[5:0]
Property 0x1100 FM_SEEK_BAND_BOTTOM
The FM_SEEK_BAND_BOTTOM property sets the bottom of the FM band for seek. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
The default is 87.5 MHz.
Default: 8750
Units: 10 kHz
FM_SEEK_BAND_BOTTOM
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FMSKFREQL[15:0]
0x222E
Bit
15:0
Name
FMSKFREQL[15:0]
Function
Sets the bottom of the FM band for seek. Default is 8750.
Range: 6400–10800, 64.0 MHz to 108.0 MHz.
Range: 8750–10790, Worldwide FM excluding Japan.
Range: 6580–7400, OIRT FM.
Range: 7600–9000, Japan FM.
Rev. 0.3
85
AN645
Property 0x1101 FM_SEEK_BAND_TOP
The FM_SEEK_BAND_TOP property sets the top of the FM band for seek. The CTS bit (and optional interrupt) is
set when it is safe to send the next command. This property may only be set or read in powerup mode. The default
is 107.9 MHz
Default: 10790
Units: 10 kHz
FM_SEEK_BAND_TOP
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FMSKFREQH[15:0]
0x2A26
Bit
Name
15:0
Function
FMSKFREQH[15:0]
Sets the top of the FM band for seek. Default is 10790.
Range: 6400–10800, 64.0 MHz to 108.0 MHz.
Range: 8750–10790, Worldwide FM excluding Japan.
Range: 6580–7400, OIRT FM.
Range: 7600–9000, Japan FM.
Property 0x1102 FM_SEEK_FREQUENCY_SPACING
The FM_SEEK_FREQUENCY_SPACING property selects frequency spacing for FM seek. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode. The default is 100 kHz.
Default: 10
Units: 10 kHz
FM_SEEK_FREQUENCY_SPACING
15
86
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0x000
FMSKSPACE[4:0]
0x000
0x0A
Bit
Name
15:5
Reserved
4:0
FMSKSPACE[4:0]
Rev. 0.3
0
Function
Always write 0.
Selects frequency spacing for FM
seek. Default is 10. Range is 1–31.
AN645
Property 0x1200 FM_RSQ_INTERRUPT_SOURCE
The FM_RSQ_INTERRUPT_SOURCE property configures interrupt related to Received Signal Quality metrics.
The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set
or read in powerup mode. The default is 0.
Default: 0
FM_RSQ_INTERRUPT_SOURCE
15
14
13
12
11
10
9
8
7
6
0x00
MULTHINT
MULTLINT
0x00
0
0
5
4
3
2
0
SNRHINT
SNRLINT
0
0
0
1
0
RSSIHINT RSSILINT
0
0
Bit
Name
Function
15:8
Reserved
7
MULTHINT
0: Disable Interrupt.
1:Enable interrupt if Multipath level goes above the threshold set by FM_RSQ_MULTIPATH_HIGH_THRESHOLD.
6
MULTLINT
0: Disable Interrupt.
1: Enable interrupt if Multipath level falls below the threshold set by FM_RSQ_MULTIPATH_LOW_THRESHOLD.
5:4
Reserved
Always write 0.
3
SNRHINT
0: Disable Interrupt.
1: Enable interrupt if SNR goes above the threshold set by FM_RSQ_SNR_HIGH_THRESHOLD.
2
SNRLINT
0: Disable Interrupt.
1: Enable interrupt if SNR falls below the threshold set by FM_RSQ_SNR_LOW_THRESHOLD.
1
RSSIHINT
0: Disable Interrupt.
1: Enable interrupt if RSSI goes above the threshold set by FM_RSQ_RSSI_HIGH_THRESHOLD.
0
RSSILINT
0: Disable Interrupt.
1: Enable interrupt if RSSI falls below the threshold set by FM_RSQ_RSSI_LOW_THRESHOLD.
Always write 0.
Rev. 0.3
87
AN645
Property 0x1201 FM_RSQ_SNR_HIGH_THRESHOLD
The FM_RSQ_SNR_HIGH_THRESHOLD property sets the high threshold, which triggers the RSQ interrupt if the
SNR is above this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command.
This property may only be set or read in powerup mode.
Default: 127
Units: dB
FM_RSQ_SNR_HIGH_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
0x00
SNRH[7:0]
0x00
0x7F
Bit
Name
15:8
Reserved
7:0
SNRH [7:0]
2
1
0
Function
Write 0 for (+) values and 0xFF for (–) values.
Sets the high threshold, which triggers the RSQ interrupt if the SNR is above this
threshold. Default is 127 dB. Range is –128 to 27 in steps of 1 dB.
Property 0x1202 FM_RSQ_SNR_LOW_THRESHOLD
The FM_RSQ_SNR_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if the SNR
is below this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
property may only be set or read in powerup mode.
Default: –128
Units: dB
FM_RSQ_SNR_LOW_THRESHOLD
15
88
14
13
12
11
10
9
8
7
6
5
4
3
0xFF
SNRL[7:0]
0xFF
0x80
Bit
Name
15:8
Reserved
7:0
SNRL [7:0]
2
1
0
Function
Write 0 for (+) values and 0xFF for (–) values.
Sets low threshold, which triggers the RSQ interrupt if the SNR is below this
threshold. Default is –128 dB. Range is –128 to 127 in steps of 1 dB.
Rev. 0.3
AN645
Property 0x1203 FM_RSQ_RSSI_HIGH_THRESHOLD
The FM_RSQ_RSSI_HIGH_THRESHOLD property sets the high threshold, which triggers the RSQ interrupt if
RSSI is above this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command.
This property may only be set or read in powerup mode.
Default: 127
Units: dBµV
FM_RSQ_RSSI_HIGH_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
0x00
0x00
Bit
Name
15:8
Reserved
7:0
RSSIH [7:0]
4
3
2
1
0
RSSIH[7:0]
0x7F
Function
Write 0 for (+) values and 0xFF for (–) values.
Sets high threshold, which triggers the RSQ interrupt if the RSSI is above
this threshold. Default is 127 dBµV. Range is –128 to 127 in steps of 1 dB.
Property 0x1204 FM_RSQ_RSSI_LOW_THRESHOLD
The FM_RSQ_RSSI_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if the RSSI
is below this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
property may only be set or read in powerup mode.
Default: –128
Units: dBµV
FM_RSQ_RSSI_LOW_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
0xFF
RSSIL[7:0]
0xFF
0x80
Bit
Name
15:8
Reserved
7:0
RSSIL [7:0]
2
1
0
Function
Write 0 for (+) values and 0xFF for (–) values.
Sets low threshold, which triggers the RSQ interrupt if the RSSI is below this
threshold. Default is –128 dBµV. Range is –128 to 127 in steps of 1 dB.
Rev. 0.3
89
AN645
Property 0x1207 FM_RSQ_MULTIPATH_HIGH_THRESHOLD
The FM_RSQ_MULTIPATH_HIGH_THRESHOLD property sets the high threshold, which triggers the RSQ
interrupt if Multipath is above this threshold. Multipath is a measure of AM modulation and can exceed 100%. The
CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or
read in powerup mode.
Default: 127
FM_RSQ_MULTIPATH_HIGH_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
0x000
MULTH[6:0]
0x000
0x7F
Bit
Name
15:7
Reserved
6:0
MULTH [6:0]
2
1
0
Function
Always write 0.
Sets the high threshold, which triggers the RSQ interrupt if Multipath is
above this threshold. Default is 127. Range is 0–127.
Property 0x1208 FM_RSQ_MULTIPATH_LOW_THRESHOLD
The FM_RSQ_MULTIPATH_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if
Multipath is below this threshold. Multipath is a measure of AM modulation and can exceed 100%. The CTS bit
(and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 0
FM_RSQ_MULTIPATH_LOW_THRESHOLD
15
90
14
13
12
11
10
9
8
7
6
5
4
3
0x000
MULTL[6:0]
0x000
0x00
Bit
Name
15:7
Reserved
6:0
MULTL[6:0]
2
1
0
Function
Always write 0.
Sets low threshold, which triggers the RSQ interrupt if Multipath is below this
threshold. Default is 0. Range is 0–127.
Rev. 0.3
AN645
Property 0x1300 FM_ACF_INTERRUPT_SOURCE
The FM_ACF_INTERRUPT_SOURCE property enables the ACF interrupt sources. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0
FM_ACF_INTERRUPT_SOURCE
15 14 13 12 11 10 9 8 7 6 5
4
3
2
0x000
BLEND_INT
HIBLEND_INT
HICUT_INT
0x000
0
0
0
Bit
Name
15:5
Reserved
4
BLEND_INT
3
HIBLEND_INT
1
0
CHBW_INT SOFTMUTE_INT
0
0
Function
Always write 0.
When set, enables the blend interrupt. Default is 0.
0 = The blend interrupt is disabled.
1 = The blend interrupt is enabled.
When set, enables the Hi-blend Interrupt. Default is 0.
0 = The Hi-blend interrupt is disabled.
1 = The Hi-blend interrupt is enabled.
2
HICUT_INT
When set, enables the Hi-cut interrupt. Default is 0.
0 = The Hi-cut interrupt is disabled.
1 = The Hi-cut interrupt is enabled.
1
CHBW_INT
When set, enables the Channel Filter Bandwidth Interrupt. Default is 0.
0 = The Channel Filter Bandwidth interrupt is disabled.
1 = The Channel Filter Bandwidth interrupt is enabled.
0
SOFTMUTE_INT
When set, enables the blend interrupt. Default is 0.
0 = The softmute interrupt is disabled.
1 = The softmute interrupt is enabled.
Rev. 0.3
91
AN645
Property 0x1301 FM_ACF_SM_THRESHOLD
The FM_ACF_SM_THRESHOLD property sets the softmute interrupt threshold in dB. When softmute attenuation
rises above the level set by this property and the SOFTMUTE_INT interrupt is enabled through the
FM_ACF_INTERRUPT_SOURCE property, the SOFTMUTE_INT interrupt will be asserted. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in the
powerup mode.
Default: 31
Units: dB
FM_ACF_SM_THRESHOLD
15
13
12
11
10
9
8
7
6
5
4
3
2
1
0x000
SMATTN_THRESH[4:0]
0x000
0x1F
Bit
Name
15:5
Reserved
4:0
92
14
SMATTN_THRESH[4:0]
0
Function
Always write 0.
Softmute interrupt threshold in dB, which triggers the softmute interrupt
when the softmute attenuation rises above this level.
Default is 31 dB
Range is 0–31 dB.
Rev. 0.3
AN645
Property 0x1302 FM_ACF_CHBW_THRESHOLD
The FM_ACF_CHBW_THRESHOLD property sets the Channel Filter Bandwidth interrupt threshold in units of kHz.
When the channel filter bandwidth falls below this threshold and the CHBW_INT interrupt is enabled through the
FM_ACF_INTERRUPT_SOURCE property, the CHBW_INT interrupt will be asserted. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0
Units: kHz
FM_ACF_CHBW_THRESHOLD
15
14
13
12
10
9
8
7
6
5
4
3
2
0x00
CHBW_THRESH[7:0]
0x00
0x00
Bit
Name
15:8
Reserved
7:0
11
1
0
Function
Always write 0.
Channel Filter Bandwidth interrupt threshold in units of kHz, which triggers
the Channel Filter Bandwidth Interrupt when the channel filter bandwidth falls
CHBW _THRESH[7:0] below this threshold.
Default is 0 kHz
Range is 0–255 kHz.
Rev. 0.3
93
AN645
Property 0x1303 FM_ACF_HICUT_THRESHOLD
The FM_ACF_HICUT_THRESHOLD property sets the Hi-cut interrupt threshold in units of 100 Hz. When the Hicut cutoff frequency falls below this threshold and the HICUT_INT interrupt is enabled through the
FM_ACF_INTERRUPT_SOURCE property, the HICUT_INT interrupt will be asserted. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0
Units: 100 Hz
FM_ACF_HICUT_THRESHOLD
15
13
12
11
10
9
8
7
6
5
4
3
2
0x00
HICUT_THRESH[7:0]
0x00
0x00
Bit
Name
15:8
Reserved
7:0
94
14
HICUT_THRESH[7:0]
1
0
Function
Always write 0.
Hi-cut interrupt threshold in units of 100 Hz, which triggers the Hi-cut Interrupt when the Hi-cut cutoff frequency falls below this threshold.
Default is 0.
Range is 0–200.
Rev. 0.3
AN645
Property 0x1304 FM_ACF_HIBLEND_THRESHOLD
The FM_ACF_HIBLEND_THRESHOLD property sets the HiBlend interrupt threshold in units of 100 Hz. When the
Hi-blend cutoff frequency falls below this threshold and the HIBLEND_INT interrupt is enabled through the
FM_ACF_INTERRUPT_SOURCE property, the HIBLEND_INT interrupt will be asserted. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 0
Units: 100 Hz
FM_ACF_HIBLEND_THRESHOLD
15
14
13
12
10
9
8
7
6
5
4
3
2
0x00
HIBLEND_THRESH[7:0]
0x00
0x00
Bit
Name
15:8
Reserved
7:0
11
1
0
Function
Always write 0.
Hi-blend interrupt threshold in units of 100 Hz, which triggers the Hi-blend
Interrupt when the Hi-blend cutoff frequency falls below this threshold.
HIBLEND_THRESH[7:0]
Default is 0.
Range is 0–200.
Rev. 0.3
95
AN645
Property 0x1305 FM_ACF_BLEND_THRESHOLD
The FM_ACF_BLEND_THRESHOLD property sets the interrupt trigger threshold for stereo blend. The threshold is
expressed as a percentage in terms of L minus R (L – R) gain factor K. When the L–R gain falls below this
threshold and the BLEND_INT is enabled through the FM_ACF_INTERRUPT_SOURCE property, the BLEND_INT
will be asserted. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property
may only be set or read in powerup mode.
Note: Stereo Separation S = (1 + K) / (1 – K), where K is the L minus R gain factor. Stereo separation of 1 implies mono mode
and stereo separation of >1 implies that the part is in stereo with up to 20 log(S) dB of stereo separation. This property
expresses the threshold value of K as a percentage. For example, value 0x0032 = a K of 50%, or a stereo separation of
S = (1.5 / 0.5) = 3. The interrupt would then trigger at 20 log(3) = 9.5 dB of stereo separation.
Default: 0
Units: % L-R gain
FM_ACF_BLEND_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
0x000
BLEND_THRESH[6:0]
0x000
0x00
1
0
Bit
Name
15:7
Reserved
Always write 0.
6:0
BLEND_
THRESH
[6:0]
Stereo Blend Interrupt threshold in units of % L-R gain, which triggers the Blend threshold
interrupt when L-R gain falls below this threshold.
Default is 0%.
Range is 0–100%.
96
Function
Rev. 0.3
AN645
Property 0x1306 FM_ACF_CONTROL_SOURCE
The FM_ACF_CONTROL_SOURCE property determines the controlling metric for ACF features. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 1
FM_ACF_CONTROL_SOURCE
15
14
Bit
Name
15:1
Reserved
13
12
11
10
9
8 7 6 5 4
3
2
1
0
0x0000
AFC_SM
0
RSSI_SM
0x0000
0
0
1
Function
Always write 0.
default: 0. When set, softmute will be triggered by an AFC rail.
2
AFC_SM
0 = Do not use AFC rail to force a softmute.
1 = Use AFC rail to force a softmute.
1
Reserved
Always write 0.
0
RSSI_SM
default: 1. When set, RSSI will be used instead of SNR as the controlling metric for
softmute.
0 = Use SNR as the controlling metric for softmute.
1 = Use RSSI as the controlling metric for softmute.
Rev. 0.3
97
AN645
Property 0x2000 FM_VALID_MAX_TUNE_ERROR
The FM_VALID_MAX_TUNE_ERROR property sets the maximum freq error allowed in units of 2 ppm before
setting the AFC rail indicator (AFCRL). The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 75 (150 ppm)
Units: 2 ppm
FM_VALID_MAX_TUNE_ERROR
15
14
13
12
11
10
9
8
7
6
5
4
3
2
0x00
FMMAXTUNEERR[7:0]
0x00
0x4B
Bit
Name
15:8
Reserved
7:0
FMMAXTUNEERR
[7:0]
1
0
Function
Always write 0.
Sets the maximum freq error allowed in units of 2 ppm before setting the AFC
rail indicator (AFCRL). Default is 75. Range is 0–126.
Property 0x2001 FM_VALID_RSSI_TIME
The FM_VALID_RSSI_TIME property sets the amount of time in milliseconds to allow the RSSI metric to settle
before evaluating.
This parameter is valid only if TUNEMODE[1:0] (FM_TUNE_FREQ) is set to 0. The minimum RSSI settling delay is
3 milliseconds. The reliability of the valid bit for identifying valid stations relies on this parameter being set properly.
The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set
or read in powerup mode.
Default: 6
Units: ms
FM_VALID_RSSI_TIME
15
98
14
13
12
11
10
9
8
7
6
5
4
3
0x00
SSIVALTIME[7:0]
0x00
0x06
Bit
Name
15:8
Reserved
7:0
SSIVALTIME[7:0]
2
1
0
Function
Always write 0.
Validation time in milliseconds. Default is 6 ms.
Range is 3–63 ms.
Rev. 0.3
AN645
Property 0x2002 FM_VALID_SNR_TIME
The FM_VALID_SNR_TIME property sets the amount of time in milliseconds to allow the SNR metric to settle
before evaluating.
This parameter is valid only if TUNEMODE[1:0] (FM_TUNE_FREQ) is set to 0. The minimum SNR settling delay is
4 ms. The reliability of the valid bit for identifying valid stations relies on this parameter being set properly. The CTS
bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 18
Units: ms
FM_VALID_SNR_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
0x00
SNRVALTIME[7:0]
0x00
0x12
Bit
Name
15:8
Reserved
7:0
SNRVALTIME[7:0]
2
1
0
Function
Always write 0.
Validation time in milliseconds. Default is
18 ms.
Range is 4–63 ms.
Property 0x2003 FM_VALID_SNR_THRESHOLD
The FM_VALID_SNR_THRESHOLD property sets the SNR threshold for a valid FM Seek/Tune. If the desired
channel SNR is above this threshold, then it is considered valid. The CTS bit (and optional interrupt) is set when it
is safe to send the next command. This property may only be set or read in powerup mode.
Default: 8
Units: dB
FM_VALID_SNR_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
0x00
FMVALSNR[7:0]
0x00
0x08
Bit
Name
15:8
Reserved
7:0
FMVALSNR [7:0]
2
1
0
Function
Write 0 for (+) values and 0xFF for (–) values.
Sets the SNR threshold for a valid FM Seek/Tune. Default is 8 dB.
Range is –128 to 127 in steps of 1 dB.
–128 = SNR is not used as a criterion in determining the validity of a station.
Rev. 0.3
99
AN645
Property 0x2004 FM_VALID_RSSI_THRESHOLD
The FM_VALID_RSSI_THRESHOLD property sets the RSSI threshold for a valid FM Seek/Tune. If the desired
channel RSSI is above this threshold, then it is considered valid. The CTS bit (and optional interrupt) is set when it
is safe to send the next command. This property may only be set or read in powerup mode.
Default: 12
Units: dBµV
FM_VALID_RSSI_THRESHOLD
15
14
13
12
10
9
8
7
6
5
4
3
0x00
FMVALRSSI[7:0]
0x00
0x0C
Bit
Name
15:8
Reserved
7:0
11
2
1
0
Function
Always write 0.
FMVALRSSI[7:0]
Sets the RSSI threshold for a valid FM Seek/Tune. Default is 12 dBµV.
Range is –128 to 127 in steps of 1 dB.
–128 = RSSI is not used as a criterion in determining the validity of a station.
Property 0x200A FM_VALID_ASSI_THRESHOLD
The FM_VALID_ASSI_THRESHOLD property sets the ASSI threshold for valid FM Seek/Tune. If the desired
channel ASSI is below this threshold, then it is considered valid. The CTS bit (and optional interrupt) is set when it
is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0x503C
Units: ms
FM_VALID_ASSI_THRESHOLD
15
14
13
12
11
9
8
7
6
5
4
3
2
FMVALASSI200[6:0]
0
FMVALASSI100[6:0]
0x50
0
0x3C
Bit
Name
15
Reserved
14:8
FMVALASSI200[6:0]
7
Reserved
6:0
FMVALASSI100[6:0]
100
10
Function
Always write 0.
Sets the ASSI200 threshold for valid FM Seek/Tune.
Default is 80 dB.
Range is 0 to 127 dB.
Always write 0.
Sets the max(HASSI,LASSI) threshold for valid FM Seek/Tune.
Default is
60 dB. Range is 0 to 127 dB.
Rev. 0.3
1
0
AN645
Property 0x2200 FM_CHBW_SQ_MIN_MAX
The FM_CHBW_SQ_MIN_MAX property sets the maximum and minimum channel filter bandwidth in kHz based
on RSSI. To force a given channel filter bandwidth, set the min and max to the same value. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 0x9637
Units: kHz
FM_CHBW_SQ_MIN_MAX
15
14
13
12
11
10
9
8
7
6
5
4
3
MAX[7:0]
MIN[7:0]
0x96
0x37
Bit
Name
15:8
MAX [7:0]
Sets the maximum channel filter bandwidth in kHz.
Default is 150 kHz
Range is 1–150 kHz.
7:0
MIN [7:0]
Sets the minimum channel filter bandwidth in kHz.
Default is 55 kHz.
Range is 1–150 kHz.
2
1
0
Function
Property 0x2201 FM_CHBW_SQ_HIGH_THRESHOLD
The FM_CHBW_SQ_HIGH_THRESHOLD property sets the RSSI/deviation threshold for maximum channel filter
bandwidth. This engine is only enabled when RSSI is above the FM_CHBW_WEAKSIG_THR. If the instantaneous
RSSI is greater than or equal to the programmed RSSI high threshold then the channel filter bandwidth will be set
to the maximum value programmed through Property 0x2200. The CTS bit (and optional interrupt) is set when it is
safe to send the next command. This property may only be set or read in powerup mode.
Default: 12
Units: dBµV
FM_CHBW_SQ_HIGH_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RSSIMAX[15:0]
0x000C
Bit
15:0
Name
RSSIMAX[15:0]
Function
Sets the RSSI threshold for maximum channel filter bandwidth.
Default is 12 dBµV
Range is –128 to 127 dBµV.
Rev. 0.3
101
AN645
Property 0x2202 FM_CHBW_SQ_LOW_THRESHOLD
The FM_CHBW_SQ_LOW_THRESHOLD property sets the RSSI threshold for minimum channel filter bandwidth.
This engine is only enabled when RSSI is above the FM_CHBW_WEAKSIG_THR. If the instantaneous RSSI is
less than or equal to the programmed RSSI low threshold then the channel filter bandwidth will be set to the
minimum value programmed through Property 0x2200. The CTS bit (and optional interrupt) is set when it is safe to
send the next command. This property may only be set or read in powerup mode.
Default: –4
Units: dBµV
FM_CHBW_SQ_LOW_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RSSIMIN[15:0]
0xFFFC
Bit
Name
Function
15:0
RSSIMIN[15:0]
Sets the RSSI threshold for minimum channel filter bandwidth.
Default is –4 dBµV
Range is 128 to –127 dBµV.
Property 0x2203 FM_CHBW_SQ_WIDENING_TIME
The FM_CHBW_SQ_WIDENING_TIME property sets the channel filter bandwidth widening time based on RSSI.
This engine is only enabled when RSSI is above the FM_CHBW_WEAKSIG_THR. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 16
Units: ms
FM_CHBW_SQ_WIDENING_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
WIDENING_TIME[15:0]
0x0010
Bit
15:0
102
Name
WIDENING_TIME[15:0]
Function
Sets the RSSI based channel filter bandwidth widening
time.
Default is 16 ms
Range is 1–32767 ms.
Rev. 0.3
0
AN645
Property 0x2204 FM_CHBW_SQ_NARROWING_TIME
The FM_CHBW_SQ_NARROWING_TIME property sets the channel filter bandwidth narrowing time based on
RSSI. This engine is only enabled when RSSI is above the FM_CHBW_WEAKSIG_THR. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 2048
Units: ms
FM_CHBW_SQ_NARROWING_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
NARROWING_TIME[15:0]
0x0800
Bit
15:0
Name
NARROWING_TIME[15:0]
Function
Sets the RSSI based channel filter bandwidth narrowing
time.
Default is 2048 ms.
Range is 1–32767 ms.
Rev. 0.3
103
AN645
Property 0x2205 FM_CHBW_ASSI_MIN_MAX
The FM_CHBW_ASSI_MIN_MAX property sets the maximum and minimum Channel Filter Bandwidth in kHz
based on 100 kHz blocker delta (difference between HASSI and LASSI). To force a given channel filter bandwidth,
set the min and max to the same value. The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 0x9623
Units: kHz
FM_CHBW_ASSI_MIN_MAX
15
14
13
12
11
10
9
8
7
6
5
4
3
MAX[7:0]
MIN[7:0]
0x96
0x23
Bit
Name
15:8
MAX [7:0]
Sets the maximum channel filter bandwidth in kHz.
Default is 150 kHz.
Range is 1–150 kHz.
7:0
MIN [7:0]
Sets the minimum channel filter bandwidth in kHz.
Default is 35 kHz.
Range is 1–150 kHz.
2
1
0
Function
Property 0x2206 FM_CHBW_ASSI_LOW_THRESHOLD
The FM_CHBW_ASSI_LOW_THRESHOLD property sets the 100 kHz blocker delta (difference between HASSI
and LASSI) threshold for maximum channel filter bandwidth. If the 100 kHz blocker delta is less than or equal to the
programmed ASSI low threshold, then the channel filter bandwidth will be set to the maximum value programmed
through Property 0x2205. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
command may only be sent in powerup mode.
Default: 7
Units: dB
FM_CHBW_ASSI_LOW_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
ASSIMIN[15:0]
0x0007
Bit
15:0
104
Name
ASSIMIN[15:0]
Function
Sets the 100 kHz blocker delta threshold for maximum channel filter
bandwidth.
Default is 7 dB.
Range is –128 to 127 dB.
Rev. 0.3
0
AN645
Property 0x2207 FM_CHBW_ASSI_HIGH_THRESHOLD
The FM_CHBW_ASSI_HIGH_THRESHOLD property sets the 100 kHz blocker delta (difference between HASSI
and LASSI) threshold for minimum channel filter bandwidth. If the 100 kHz blocker delta is greater than the
programmed ASSI high threshold, then the channel filter bandwidth will be set to the minimum value programmed
through Property 0x2205. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
command may only be sent in powerup mode.
Default: 20
Units: dB
FM_CHBW_ASSI_HIGH_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ASSIMAX[15:0]
0x0014
Bit
Name
15:0
Function
ASSIMAX[15:0]
Sets the 100 kHz blocker delta threshold for minimum channel filter
bandwidth.
Default is 20 dB.
Range is –128 to 127 dB.
Property 0x2208 FM_CHBW_ASSI_WIDENING_TIME
The FM_CHBW_ASSI_WIDENING_TIME property sets the channel filter bandwidth widening time based on the
100 kHz blocker delta (difference between HASSI and LASSI). The CTS bit (and optional interrupt) is set when it is
safe to send the next command. This command may only be sent in powerup mode.
Default: 3200
Units: ms
FM_CHBW_ASSI_WIDENING_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
WIDENING_TIME[15:0]
0x0C80
Bit
15:0
Name
Function
Sets the 100 kHz blocker delta based channel filter bandwidth widening
time.
WIDENING_TIME[15:0]
Default is 3200 ms.
Range is 1–32767 ms.
Rev. 0.3
105
AN645
Property 0x2209 FM_CHBW_ASSI_NARROWING_TIME
The FM_CHBW_ASSI_NARROWING_TIME property sets the channel filter bandwidth narrowing time based on
the 100 kHz blocker delta (difference between HASSI and LASSI). The CTS bit (and optional interrupt) is set when
it is safe to send the next command. This command may only be sent in powerup mode.
Default: 320
Units: ms
FM_CHBW_ASSI_NARROWING_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
NARROWING_TIME[15:0]
0x0140
Bit
Name
15:0
Function
NARROWING_TIME[15:0]
Sets the 100 kHz blocker delta based channel filter bandwidth narrowing time.
Default is 320 ms.
Range is 1–32767 ms.
Property 0x220A FM_CHBW_ASSI200_MIN_MAX
The FM_CHBW_ASSI200_MIN_MAX property sets the maximum and minimum channel filter bandwidth in kHz
based on 200 kHz blocker strength. To force a given channel filter bandwidth, set the min and max to the same
value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only
be set or read in powerup mode.
Default: 0x9650
Units: kHz
FM_CHBW_ASSI200_MIN_MAX
15
14
12
11
10
9
8
7
6
5
4
3
MAX[7:0]
MIN[7:0]
0x96
0x50
2
1
Bit
Name
15:8
MAX[7:0]
Sets the maximum channel filter bandwidth in kHz.
Default is 150 kHz.
Range is 1–150 kHz.
MIN[7:0]
Sets the minimum channel filter bandwidth in kHz.
Default is 80 kHz.
Range is 1–150 kHz.
7:0
106
13
Function
Rev. 0.3
0
AN645
Property 0x220B FM_CHBW_ASSI200_LOW_THRESHOLD
The FM_CHBW_ASSI200_LOW_THRESHOLD property sets the 200 kHz blocker strength threshold for maximum
channel filter bandwidth. If the 200 kHz blocker strength is less than or equal to the programmed ASSI200 low
threshold, then the channel filter bandwidth will be set to the maximum value programmed through Property
0x220A. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may
only be sent in powerup mode.
Default: –10
Units: dB relative to desired channel RSSI
FM_CHBW_ASSI200_LOW_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ASSI200MIN[7:0]
0xFFF6
Bit
Name
15:0
Function
Sets the 200 kHz blocker strength threshold for maximum
channel filter bandwidth.
Default is –10 dB (relative to desired channel RSSI)
Range is –128 to 127 dBr.
ASSI200MIN[15:0]
Property 0x220C FM_CHBW_ASSI200_HIGH_THRESHOLD
The FMCHBW_ASSI200_HIGH_THRESHOLD property sets the 200 kHz blocker strength threshold for minimum
channel filter bandwidth. If the 200 kHz blocker strength is greater than the programmed ASSI200 high threshold,
then the channel filter bandwidth will be set to the minimum value programmed through Property 0x220A. The CTS
bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in
powerup mode.
Default: 10
Units: dB relative to desired channel RSSI
FM_CHBW_ASSI200_HIGH_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ASSI200MAX[7:0]
0x000A
Bit
15:0
Name
ASSI200MAX[15:0]
Function
Sets the 200 kHz blocker strength threshold for maximum
channel filter bandwidth.
Default is 10 dB (relative to desired channel RSSI)
Range is –128 to 127 dBr.
Rev. 0.3
107
AN645
Property 0x220D FM_CHBW_ASSI200_WIDENING_TIME
The FM_CHBW_ASSI200_WIDENING_TIME property sets the channel filter bandwidth widening time based on
the 200 kHz blocker strength. The CTS bit (and optional interrupt) is set when it is safe to send the next command.
This command may only be sent in powerup mode.
Default: 3200
Units: ms
FM_CHBW_ASSI200_WIDENING_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
WIDENING_TIME[15:0]
0x0C80
Bit
Name
15:0
Function
Sets the 200 kHz blocker strength based channel filter
bandwidth widening time.
Default is 3200 ms.
Range is 1–32767 ms.
WIDENING_TIME[15:0]
Property 0x220E FM_CHBW_ASSI200_NARROWING_TIME
The FM_CHBW_ASSI200_NARROWING_TIME property sets the channel filter bandwidth narrowing time based
on the 200 kHz blocker strength. The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This command may only be sent in powerup mode.
Default: 320
Units: ms
FM_CHBW_ASSI200_NARROWING_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
NARROWING_TIME[15:0]
0x0140
Bit
15:0
108
Name
Function
NARROWING_TIME[15:0]
Sets the 200 kHz blocker strength based channel filter bandwidth narrowing time.
Default is 320 ms.
Range is 1–32767 ms.
Rev. 0.3
AN645
Property 0x220F FM_CHBW_WEAKSIG_THR
The FM_CHBW_WEAKSIG_THR property sets the RSSI value at which the engine will engage (LOW) and
disengage (HIGH) for the weak signal channel filter bandwidth engine.
Default: 0x100D
FM_CHBW_WEAKSIG_THR
15
14
13
12
11
10
9
8
7
6
5
4
3
2
HIGH[7:0]
LOW[7:0]
0x10
0x0D
1
0
Bit
Name
Function
15:8
HIGH[7:0]
When RSSI is above this value, the weak signal channel filter bandwidth engine disengages. Default: 0x10.
7:0
LOW[7:0]
When RSSI is below this value, the weak signal channel filter bandwidth engine
engages. Default: 0x0D.
Property 0x3105 FM_LOWCUT_MIN_FREQ
The FM_LOWCUT_MIN_FREQ property sets the minimum cutoff frequency. The LowCut tracks the HICUT
engine; therefore, thresholds are programmed in HICUT threshold properties (0x3600, 0x3604, 0x3608, 0x360C,
0x3610, 0x3614) and the HIBLEND threshold properties (0x3700, 0x3740, 0x3708, 0x370C, 0x3710, 0x3714).
Setting the property to 0 disables LowCut. The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read in powerup mode.
Default: 0
Units: Hz
FM_LOWCUT_MIN_FREQ
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FREQ_MIN[15:0]
0x0000
Bit
15:0
Name
FREQ_MIN[15:0]
Function
Sets the minimum LOW-CUT cutoff frequency in Hz.
Default is disabled.
Range is 8–1000 Hz.
0 = Disabled.
Rev. 0.3
109
AN645
Property 0x3106 FM_LOWCUT_MAX_FREQ
The FM_LOWCUT_MAX_FREQ property sets the maximum cutoff frequency. The LowCut tracks the HICUT
engine, therefore thresholds are programmed in HICUT threshold properties (0x3600, 0x3604, 0x3608, 0x360C,
0x3610, 0x3614) and the HIBLEND threshold properties (0x3700, 0x3740, 0x3708, 0x370C, 0x3710, 0x3714). The
CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or
read in powerup mode.
Default: 0
Units: Hz
FM_LOWCUT_MIN_FREQ
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FREQ_MAX[15:0]
0x0000
Bit
15:0
110
Name
Function
FREQ_MAX[15:0]
Sets the maximum LOW-CUT cutoff frequency in Hz. Note
that if property 0x3105 (FM_LOWCUT_MIN_FREQ) is nonzero, this property must be set to a value no less than property 0x3105.
Default is 0 Hz.
Range is 0–1000 Hz.
Rev. 0.3
AN645
Property 0x3300 FM_IBOC_CONTROL
(Si4777 Only)
The FM_IBOC_CONTROL property is the control property for IBOC Blend. DIGITAL_IO_INPUT_SAMPLE_RATE
and DIGITAL_IO_INPUT_FORMAT must be configured before IBOC Blend will function. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0x0000
FM_IBOC_CONTROL
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0x00
FORCE
0x00
ENABLE
0x00
0
0x00
0
Bit
Name
15:9
Reserved
Function
Always write 0.
Forces IBOC Blend. Default is 0.
0 = Do not force IBOC blend. The audio source is determined by the IBOC control pin.
1 = Force IBOC blend. The audio is sourced from the IBOC system
8
FORCE
7:1
Reserved
Always write 0.
0
ENABLE
ENABLE - IBOC Blend Enable. Default is 0.
0 = The IBOC Blend system is disabled.
1 = The IBOC Blend system is enabled.
Property 0x3301 FM_IBOC_ANALOG_TO_HD_CROSSFADE_TIME
(Si4777 Only)
The FM_IBOC_ANALOG_TO_HD_CROSSFADE_TIME property sets the crossfade time between full analog and
full HD Digital audio in ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command.
This property may only be set or read in powerup mode.
Default: 1000
Units: ms
FM_IBOC_ANALOG_TO_HD_CROSSFADE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TIME[15:0]
0x03E8
Bit
Name
15:0
TIME[15:0]
Function
Sets the full analog to full digital crossfade time in ms.
Default is 1000 ms.
Range is 0–22000 ms.
Rev. 0.3
111
AN645
Property 0x3302 FM_IBOC_HD_TO_ANALOG_CROSSFADE_TIME
(Si4777 Only)
The FM_IBOC_HD_TO_ANALOG_CROSSFADE_TIME property sets the crossfade time from full HD Digital to full
analog audio in ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
property may only be set or read in powerup mode.
Default: 1000
Units: ms
FM_IBOC_HD_TO_ANALOG_CROSSFADE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TIME[15:0]
0x03E8
Bit
Name
Function
15:0
TIME[15:0]
Sets the full digital to full analog crossfade time in ms.
Default is 1000 ms.
Range is 0–22000 ms.
Property 0x3303 FM_IBOC_DYNAMIC_GAIN
(Si4777 Only)
The FM_IBOC_DYNAMIC_GAIN property sets the digital audio dynamic linear scaling factor. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 0x007F
FM_IBOC_DYNAMIC_GAIN
15
14
12
11
10
9
8
7
6
5
4
3
0x00
DGAIN[7:0]
0x00
0x7F
Bit
Name
15:8
Reserved
7:0
112
13
DGAIN[7:0]
Function
Always write 0.
Station dependent linear scaling factor in Q7 format.
Default is 0x7F.
Range is 0–0x7F.
Rev. 0.3
2
1
0
AN645
Property 0x3304 FM_IBOC_STATIC_GAIN
(Si4777 Only)
The FM_IBOC_STATIC_GAIN property sets the digital audio static linear gain factor. Reverse the sign of this
number to obtain a 180 degree phase shift. The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read when in the powerup mode.
Default: 0x0100
FM_IBOC_STATIC_GAIN
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SGAIN[15:0]
0x0100
Bit
Name
Function
15:0
SGAIN[15:0]
Static linear gain factor in Q7.8 format.
Default is 0x0100.
Range is 0x8000–0x7FFF.
Property 0x3400 FM_MULT_EQ_CTL
The FM_MULT_EQ_CTL property controls the multipath channel equalizer. The CTS bit (and optional interrupt) is
set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 5121
FM_MULT_EQ_CTL
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0x00
NUM_TAPS[4:0]
0x00
MULT_EQ_CTL[1:0]
0x00
0x14
0x00
0x1
Bit
Name
15:13
Reserved
12:8
NUM_TAPS[4:0]
7:2
Reserved
1:0
MULT_EQ_CTL[1:0]
Function
Always write 000.
Number of taps in the multipath equalizer. Range 1-20. For automatic selection, use 0.
Always write 000000.
Controls the Multipath channel equalizer. Default is 1
0 = Equalizer OFF
1 = Equalizer ON
Rev. 0.3
113
AN645
Property 0x3401 FM_EQ_NOISE_DISABLE_MULT_EQ
The FM_EQ_NOISE_DISABLE_MULT_EQ property sets the RSSI threshold below which the channel equalizer
will use noise measurements to enable/disable the channel equalizer. The CTS bit (and optional interrupt) is set
when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0xFC81
FM_EQ_NOISE_DISABLE_MULT_EQ
15
14
13
12
11
10
9
8
7
6
5
4
3
2
MULT_EQ_ON_LEVEL[7:0]
MULT_EQ_OFF_LEVEL[7:0]
0xFC
0x81
1
0
Bit
Name
Function
15:8
MULT_EQ_ON_LEVEL[7:0]
RSSI level above which noise measurements will not be used to
enable/disable the equalizer. Default: –4 (0xFC).
7:0
MULT_EQ_OFF_LEVEL[7:0]
RSSI level below which noise measurements will be used to
enable/disable the equalizer. Set to –127 (0x81) to disable.
Default:0x81 (disabled)
Property 0x3500 FM_BLEND_RSSI_THRESHOLDS
The FM_BLEND_RSSI_THRESHOLDS property sets the RSSI thresholds for maximum and minimum stereo
separation (set by Property 0x3501) on the blend engine. The CTS bit (and optional interrupt) is set when it is safe
to send the next command. This property may only be set or read in powerup mode.
Default: 0x3719
Units: dBµV
FM_BLEND_RSSI_THRESHOLDS
15
114
14
13
12
11
10
9
8
7
6
5
4
3
RSSIMAX[7:0]
RSSIMIN[7:0]
0x37
0x19
2
1
0
Bit
Name
Function
15:8
RSSIMAX[7:0]
Sets the RSSI Max threshold. If RSSI is above this threshold, maximum
stereo separation will be achieved as set by property 0x3501. Default is
55 dBµV. Range is –20 to 120 dBµV.
7:0
RSSIMIN[7:0]
Sets the RSSI Min threshold. If RSSI is below this threshold, minimum stereo separation will be achieved as set by property 0x3501. Default is
25 dBµV. Range is –20 to 120 dBµV.
Rev. 0.3
AN645
Property 0x3501 FM_BLEND_RSSI_STEREO_SEP
The FM_BLEND_RSSI_STEREO_SEP property sets the maximum and minimum stereo separation based on
RSSI (set by Property 0x3500) on the blend engine. You can force a constant stereo separation value by setting
ST_SEPMAX and ST_SEPMIN to the same value. To disable the stereo blend based on RSSI, set
ST_SEPMAX = ST_SEPMIN = 100 (0x64.) The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read in powerup mode.
Default: 0x2D00
Units: dB
FM_BLEND_RSSI_STEREO_SEP
15
14
13
12
11
10
9
8
7
6
5
4
3
ST_SEPMAX[7:0]
ST_SEPMIN[7:0]
0x2D
0x00
2
1
0
Bit
Name
Function
15:8
ST_SEPMAX[7:0]
Sets the maximum stereo separation. Default is 45 dB. Range is 0–64 dB.
7:0
ST_SEPMIN[7:0]
Sets the minimum stereo separation. Default is 0 dB. Range is 0–64 dB.
Property 0x3502 FM_BLEND_RSSI_ATTACK_TIME
The FM_BLEND_RSSI_ATTACK_TIME property sets the transition time for which the stereo blend mitigation
engine decreases the stereo separation based on RSSI. The CTS bit (and optional interrupt) is set when it is safe
to send the next command. This property may only be set or read in powerup mode.
Default: 16
Units: ms
FM_BLEND_RSSI_ATTACK_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK[15:0]
0x0010
Bit
Name
15:0
ATTACK[15:0]
Function
Sets the transition time for which the stereo blend mitigation engine
decreases the stereo separation based on RSSI. Default is 16 ms. Range
is 1–32767 ms.
Rev. 0.3
115
AN645
Property 0x3503 FM_BLEND_RSSI_RELEASE_TIME
The FM_BLEND_RSSI_RELEASE_TIME property sets the transition time for which the stereo blend mitigation
engine increases the stereo separation based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to
send the next command. This property may only be set or read in powerup mode.
Default: 4000
Units: ms
FM_BLEND_RSSI_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x0FA0
Bit
Name
Function
15:0
RELEASE[15:0]
Sets the transition time for which the stereo blend mitigation engine
increases the stereo separation based on RSSI. Default is 4000 ms. Range
is 1–32767 ms.
Property 0x3508 FM_BLEND_MULTIPATH_THRESHOLDS
The FM_BLEND_MULTIPATH_THRESHOLDS property sets the Multipath thresholds for maximum and minimum
stereo separation (set by Property 0x3509) on the blend engine. The CTS bit (and optional interrupt) is set when it
is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0x1E3C
FM_BLEND_MULTIPATH_THRESHOLDS
15
116
14
13
12
11
10
9
8
7
6
5
4
3
MULTMIN[7:0]
MULTMAX[7:0]
0x1E
0x3C
2
1
0
Bit
Name
Function
15:8
MULTMIN[7:0]
Sets the Multipath Min threshold. If Multipath is below this threshold, maximum stereo separation will be achieved as set by property 0x3509.
Default is 30. Range is 0–127.
7:0
MULTMAX[7:0]
Sets the Multipath Max threshold. If Multipath is above this threshold, minimum stereo separation will be achieved as set by property 0x3509.
Default is 60. Range is 0–127.
Rev. 0.3
AN645
Property 0x3509 FM_BLEND_MULTIPATH_STEREO_SEP
The FM_BLEND_MULTIPATH_STEREO_SEP property sets the maximum and minimum stereo separation based
on Multipath (set by Property 0x3508) on the blend engine. You can force a constant stereo separation value by
setting ST_SEPMAX and ST_SEPMIN to the same value. To disable the stereo blend based on Multipath, set
ST_SEPMAX = ST_SEPMIN = 100 (0x64.) The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read in powerup mode.
Default: 0x2D00
Units: dB
FM_BLEND_MULTIPATH_STEREO_SEP
15
14
13
12
11
10
9
8
7
6
5
4
3
ST_SEPMAX[7:0]
ST_SEPMIN[7:0]
0x2D
0x00
2
1
0
Bit
Name
Function
15:8
ST_SEPMAX[7:0]
Sets the maximum stereo separation. Default is 45 dB. Range is 0–64 dB.
7:0
ST_SEPMIN[7:0]
Sets the minimum stereo separation. Default is 0 dB. Range is 0–64 dB.
Property 0x350A FM_BLEND_MULTIPATH_ATTACK_TIME
The FM_BLEND_MULTIPATH_ATTACK_TIME property sets the transition time for which the stereo blend
mitigation engine decreases the stereo separation based on Multipath. The CTS bit (and optional interrupt) is set
when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 16
Units: ms
FM_BLEND_MULTIPATH_ATTACK_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK[15:0]
0x0010
Bit
Name
15:0
ATTACK[15:0]
Function
Sets the transition time for which the stereo blend mitigation engine
decreases the stereo separation based on Multipath.
Default is 16 ms. Range is 1–32767 ms.
Rev. 0.3
117
AN645
Property 0x350B FM_BLEND_MULTIPATH_RELEASE_TIME
The FM_BLEND_MULTIPATH_RELEASE_TIME property sets the transition time for which the stereo blend
mitigation engine increases the stereo separation based on RSSI. The CTS bit (and optional interrupt) is set when
it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 4000
Units: ms
FM_BLEND_MULTIPATH_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x0FA0
Bit
Name
Function
15:0
RELEASE[15:0]
Sets the transition time for which the stereo blend mitigation engine
increases the stereo separation based on Multipath.
Default is 4000 ms. Range is 1–32767 ms.
Property 0x3510 FM_BLEND_USN_THRESHOLDS
The FM_BLEND_USN_THRESHOLDS property sets the USN thresholds for maximum and minimum stereo
separation (set by Property 0x3511) on the blend engine. The CTS bit (and optional interrupt) is set when it is safe
to send the next command. This property may only be set or read in powerup mode.
Default: 0x341B
Units: –dBFS
FM_BLEND_USN_THRESHOLDS
15
14
12
11
10
9
8
7
6
5
4
3
USNMIN[7:0]
USNMAX[7:0]
0x34
0x1B
2
1
0
Bit
Name
Function
15:8
USNMIN[7:0]
Sets the USN Min threshold. If USN is below this threshold, maximum stereo separation will be achieved as set by property 0x3511.
Default is –52 dBFS. Range is 0–127 –dBFS.
USNMAX[7:0]
Sets the USN Max threshold. If USN is above this threshold, minimum stereo separation will be achieved as set by property 0x3511.
Default is –27 dBFS. Range is 0–127 –dBFS.
7:0
118
13
Rev. 0.3
AN645
Property 0x3511 FM_BLEND_USN_STEREO_SEP
The FM_BLEND_USN_STEREO_SEP property sets the maximum and minimum stereo separation based on USN
(set by Property 0x3510) on the blend engine. You can force a constant stereo separation value by setting
ST_SEPMAX and ST_SEPMIN to the same value. To disable the stereo blend based on USN, set
ST_SEPMAX = ST_SEPMIN = 100 (0x64.) The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read in powerup mode.
Default: 0x2D00
Units: dB
FM_BLEND_USN_STEREO_SEP
15
14
13
12
11
10
9
8
7
6
5
4
3
ST_SEPMAX[7:0]
ST_SEPMIN[7:0]
0x2D
0x00
2
1
0
Bit
Name
Function
15:8
ST_SEPMAX[7:0]
Sets the maximum stereo separation. Default is 45 dB. Range is 0–100 dB.
7:0
ST_SEPMIN[7:0]
Sets the minimum stereo separation. Default is 0 dB. Range is 0–100 dB.
Property 0x3512 FM_BLEND_USN_ATTACK_TIME
The FM_BLEND_USN_ATTACK_TIME property sets the transition time for which the stereo blend mitigation
engine decreases the stereo separation based on USN. The CTS bit (and optional interrupt) is set when it is safe to
send the next command. This property may only be set or read in powerup mode.
Default: 16
Units: ms
FM_BLEND_USN_ATTACK_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK[15:0]
0x0010
Bit
Name
15:0
ATTACK[15:0]
Function
Sets the transition time for which the stereo blend mitigation engine
decreases the stereo separation based on USN.
Default is 16 ms. Range is 1–32767 ms.
Rev. 0.3
119
AN645
Property 0x3513 FM_BLEND_USN_RELEASE_TIME
The FM_BLEND_USN_RELEASE_TIME property sets the transition time for which the stereo blend mitigation
engine increases the stereo separation based on USN. The CTS bit (and optional interrupt) is set when it is safe to
send the next command. This property may only be set or read in powerup mode.
Default: 4000
Units: ms
FM_BLEND_USN_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x0FA0
Bit
Name
Function
15:0
RELEASE[15:0]
Sets the transition time for which the stereo blend mitigation engine
increases the stereo separation based on USN.
Default is 4000 ms. Range is 1–32767 ms.
Property 0x3600 FM_HICUT_RSSI_THRESHOLDS
The FM_Hi-cut_RSSI_THRESHOLDS property sets the RSSI thresholds for Hi-cut to begin band limiting and
reach maximum band limiting on L+R channel based on max and min cutoff frequency (set by Property 0x3601) on
the Hi-cut engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
property may only be set or read in powerup mode.
Default: 0x230F
Units: dBµV
FM_HICUT_RSSI_THRESHOLDS
15
120
14
13
12
11
10
9
8
7
6
5
4
3
RSSIMAX[7:0]
RSSIMIN[7:0]
0x23
0x0F
2
1
0
Bit
Name
Function
15:8
RSSIMAX[7:0]
Sets the RSSI level at which Hi-cut begins to band limit on the L+R channel
based on cutoff frequency set by property 0x3601.
Default is 35 dBµV. Range is –20–120 dBµV.
7:0
RSSIMIN[7:0]
Sets the RSSI level at which Hi-cut reaches maximum band limiting on the
L+R channel based on cutoff frequency set by property 0x3601.
Default is 15 dBµV. Range is –20–120 dBµV.
Rev. 0.3
AN645
Property 0x3601 FM_HICUT_RSSI_CUTOFF_FREQ
The FM_Hi-cut_RSSI_CUTOFF_FREQ property sets the maximum and minimum cutoff frequencies based on
RSSI (set by Property 0x3600) on the Hi-cut engine. You can force a constant cutoff frequency value by setting
FREQ_MAX and FREQ_MIN to the same value. To disable the Hi-cut based on RSSI, set
FREQ_MAX = FREQ_MIN = 180 (0xB4.) The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 0xB428
Units: 100 Hz
FM_HICUT_RSSI_CUTOFF_FREQ
15
14
13
12
11
10
9
8
7
6
5
4
3
FREQ_MAX[7:0]
FREQ_MIN[7:0]
0xB4
0x28
2
1
0
Bit
Name
Function
15:8
FREQ_MAX[7:0]
Sets the maximum cutoff frequency. Default is 18 kHz. Range is 0–18 kHz.
7:0
FREQ_MIN[7:0]
Sets the minimum stereo separation. Default is 4 kHz. Range is 0–18 kHz.
Property 0x3602 FM_HICUT_RSSI_ATTACK_TIME
The FM_HI-CUT_RSSI_ATTACK_TIME property sets the transition time for which the Hi-cut mitigation engine
lowers the cutoff frequency based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read in powerup mode.
Default: 16
Units: ms
FM_HICUT_RSSI_ATTACK_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK[15:0]
0x0010
Bit
Name
15:0
ATTACK[15:0]
Function
Sets the transition time for which the Hi-cut mitigation engine lowers the
cutoff frequency based on RSSI.
Default is 16 ms. Range is 1–32767 ms.
Rev. 0.3
121
AN645
Property 0x3603 FM_HICUT_RSSI_RELEASE_TIME
The FM_HICUT_RSSI_RELEASE_TIME property sets the transition time for which the Hi-cut mitigation engine
increases the cutoff frequency based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read in powerup mode.
Default: 4000
Units: ms
FM_HICUT_RSSI_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x0FA0
Bit
Name
Function
15:0
RELEASE[15:0]
Sets the transition time for which the Hi-cut mitigation engine increases the
cutoff frequency based on RSSI.
Default is 4000 ms. Range is 1–32767 ms.
Property 0x3608 FM_HICUT_MULTIPATH_THRESHOLDS
The FM_HICUT_MULTIPATH_THRESHOLDS property sets the Multipath thresholds for Hi-cut to begin band
limiting and reach maximum band limiting on L+R channel based on max and min cutoff frequencies (set by
Property 0x3609) on the Hi-cut engine. The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 0x3250
FM_HICUT_MULTIPATH_THRESHOLDS
15
14
Bit
122
13
12
11
10
9
8
7
6
5
4
3
MULTMIN[7:0]
MULTMAX[7:0]
0x32
0x50
Name
2
1
0
Function
15:8
MULTMIN[7:0]
Sets the Multipath level at which Hi-cut reaches max band limiting on the
L+R channel based on cutoff frequency set by property 0x3609.
Default is 40. Range is 0–127%.
7:0
MULTMAX[7:0]
Sets the Multipath level at which Hi-cut begins to band limit on the L+R
channel based on cutoff frequency set by property 0x3609.
Default is 80. Range is 0–127%.
Rev. 0.3
AN645
Property 0x3609 FM_HICUT_MULTIPATH_CUTOFF_FREQ
The FM_HICUT_MULTIPATH_CUTOFF_FREQ property sets the maximum and minimum cutoff frequency based
on Multipath (set by Property 0x3608) on the Hi-cut engine. You can force a constant cutoff frequency value by
setting FREQ_MAX and FREQ_MIN to the same value. To disable the Hi-cut based on Multipath, set
FREQ_MAX = FREQ_MIN = 180 (0xB4.) The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 0xB428
Units: 100 Hz
FM_HICUT_MULTIPATH_CUTOFF_FREQ
15
14
13
12
11
10
9
8
7
6
5
4
3
FREQ_MAX[7:0]
FREQ_MIN[7:0]
0xB4
0x28
2
1
0
Bit
Name
Function
15:8
FREQ_MAX[7:0]
Sets the maximum cutoff frequency. Default is 18 kHz. Range is 0–18 kHz.
7:0
FREQ_MIN[7:0]
Sets the minimum stereo separation. Default is 4 kHz. Range is 0–18 kHz.
Property 0x360A FM_HICUT_MULTIPATH_ATTACK_TIME
The FM_HICUT_MULTIPATH_ATTACK_TIME property sets the transition time for which the Hi-cut mitigation
engine lowers the cutoff frequency based on Multipath. The CTS bit (and optional interrupt) is set when it is safe to
send the next command. This property may only be set or read in powerup mode.
Default: 16
Units: ms
FM_HICUT_MULTIPATH_ATTACK_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK[15:0]
0x0010
Bit
Name
Function
15:0
ATTACK[15:0]
Sets the transition time for which the Hi-cut mitigation engine decreases the
cutoff frequency based on Multipath.
Default is 16 ms. Range is 1–32767 ms.
Rev. 0.3
123
AN645
Property 0x360B FM_HICUT_MULTIPATH_RELEASE_TIME
The FM_HICUT_MULTIPATH_RELEASE_TIME property sets the transition time for which the Hi-cut mitigation
engine increases the cutoff frequency based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to
send the next command. This property may only be set or read in powerup mode.
Default: 4000
Units: ms
FM_HICUT_MULTIPATH_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x0FA0
Bit
Name
Function
15:0
RELEASE[15:0]
Sets the transition time for which the Hi-cut mitigation engine increases the
cutoff frequency based on Multipath.
Default is 4000 ms. Range is 1–32767 ms.
Property 0x3610 FM_HICUT_USN_THRESHOLDS
The FM_HICUT_USN_THRESHOLDS property sets the USN thresholds for Hi-cut to begin band limiting and
reach maximum band limiting on L+R channel based on max and min cutoff frequencies (set by Property 0x3611)
on the Hi-cut engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
property may only be set or read in powerup mode.
Default: 0x250F
Units: –dBFS
FM_HICUT_USN_THRESHOLDS
15
14
12
11
10
9
8
7
6
5
4
3
USNMIN[7:0]
USNMAX[7:0]
0x25
0x0F
2
1
0
Bit
Name
15:8
USNMIN[7:0]
Sets the USN level at which Hi-cut reaches max band limiting on the L+R
channel based on cutoff frequency set by property 0x3611.
Default is –37 dBFS. Range is 0–127 –dBFS.
USNMAX[7:0]
Sets the Multipath level at which Hi-cut begins to band limit on the L+R
channel based on cutoff frequency set by property 0x3611.
Default is –15 dBFS. Range is 0–127 –dBFS.
7:0
124
13
Function
Rev. 0.3
AN645
Property 0x3611 FM_HICUT_USN_CUTOFF_FREQ
The FM_HICUT_USN_CUTOFF_FREQ property sets the maximum and minimum cutoff frequency based on USN
(set by Property 0x3610) on the Hi-cut engine. You can force a constant cutoff frequency value by setting
FREQ_MAX and FREQ_MIN to the same value. To disable the Hi-cut based on USN, set
FREQ_MAX = FREQ_MIN = 180 (0xB4.) The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 0xB428
Units: 100 Hz
FM_HICUT_USN_CUTOFF_FREQ
15
14
13
12
11
10
9
8
7
6
5
4
3
FREQ_MAX[7:0]
FREQ_MIN[7:0]
0xB4
0x28
2
1
0
Bit
Name
Function
15:8
FREQ_MAX[7:0]
Sets the maximum cutoff frequency. Default is 18 kHz. Range is 0–18 kHz.
7:0
FREQ_MIN[7:0]
Sets the minimum stereo separation. Default is 4 kHz. Range is 0–18 kHz.
Property 0x3612 FM_HICUT_USN_ATTACK_TIME
The FM_HICUT_USN_ATTACK_TIME property sets the transition time for which the Hi-cut mitigation engine
lowers the cutoff frequency based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read in powerup mode.
Default: 16
Units: ms
FM_HICUT_USN_ATTACK_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK[15:0]
0x0010
Bit
Name
15:0
ATTACK[15:0]
Function
Sets the transition time for which the Hi-cut mitigation engine lowers the
cutoff frequency based on USN.
Default is 16 ms. Range is 1–32767 ms.
Rev. 0.3
125
AN645
Property 0x3613 FM_HICUT_USN_RELEASE_TIME
The FM_HICUT_USN_RELEASE_TIME property sets the transition time for which the Hi-cut mitigation engine
increases the cutoff frequency based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read in powerup mode.
Default: 4000
Units: ms
FM_HICUT_USN_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x0FA0
Bit
Name
Function
15:0
RELEASE[15:0]
Sets the transition time for which the Hi-cut mitigation engine increases the
cutoff frequency based on USN.
Default is 4000 ms. Range is 1–32767 ms.
Property 0x3700 FM_HIBLEND_RSSI_THRESHOLDS
The FM_HIBLEND_RSSI_THRESHOLDS property sets the RSSI thresholds for Hi-blend to begin band limiting
and reach maximum band limiting on L-R channel based on max and min cutoff frequency (set by Property
0x3701) on the Hi-blend engine. The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 0x371B
Units: dBµV
FM_HIBLEND_RSSI_THRESHOLDS
15
14
12
11
10
9
8
7
6
5
4
3
RSSIMAX[7:0]
RSSIMIN[7:0]
0x37
0x1B
2
1
0
Bit
Name
Function
15:8
RSSIMAX[7:0]
Sets the RSSI level at which Hi-blend begins to band limit on the L-R channel based on cutoff frequency set by property 0x3701.
Default is 55 dBµV. Range is –20 to 120 dBµV.
RSSIMIN[7:0]
Sets the RSSI level at which Hi-blend reaches maximum band limiting on
the L-R channel based on cutoff frequency set by property 0x3701.
Default is 27 dBµV. Range is –20 to 120 dBµV.
7:0
126
13
Rev. 0.3
AN645
Property 0x3701 FM_HIBLEND_RSSI_CUTOFF_FREQ
The FM_HIBLEND_RSSI_CUTOFF_FREQ property sets the maximum and minimum cutoff frequencies based on
RSSI (set by Property 0x3700) on the Hi-blend engine. You can force a constant cutoff frequency value by setting
FREQ_MAX and FREQ_MIN to the same value. To disable the Hi-blend based on RSSI, set
FREQ_MAX = FREQ_MIN = 180 (0xB4.) The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 0xB41E
Units: 100 Hz
FM_HIBLEND_RSSI_CUTOFF_FREQ
15
14
13
12
11
10
9
8
7
6
5
4
3
FREQ_MAX[7:0]
FREQ_MIN[7:0]
0xB4
0x1E
2
1
0
Bit
Name
Function
15:8
FREQ_MAX[7:0]
Sets the maximum cutoff frequency. Default is 18 kHz. Range is 0–18 kHz.
7:0
FREQ_MIN[7:0]
Sets the minimum stereo separation. Default is 3 kHz. Range is 0–18 kHz.
Property 0x3702 FM_HIBLEND_RSSI_ATTACK_TIME
The FM_HIBLEND_RSSI_ATTACK_TIME property sets the transition time for which the Hi-blend mitigation engine
lowers the cutoff frequency based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read in powerup mode.
Default: 4
Units: ms
FM_HIBLEND_RSSI_ATTACK_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK[15:0]
0x0004
Bit
Name
Function
15:0
ATTACK[15:0]
Sets the transition time for which the Hi-blend mitigation engine lowers the
cutoff frequency based on RSSI.
Default is 4 ms. Range is 1–32767 ms.
Rev. 0.3
127
AN645
Property 0x3703 FM_HIBLEND_RSSI_RELEASE_TIME
The FM_HIBLEND_RSSI_RELEASE_TIME property sets the transition time for which the Hi-blend mitigation
engine increases the cutoff frequency based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to
send the next command. This property may only be set or read in powerup mode.
Default: 8000
Units: ms
FM_HIBLEND_RSSI_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x1F40
Bit
Name
Function
15:0
RELEASE[15:0]
Sets the transition time for which the Hi-blend mitigation engine increases
the cutoff frequency based on RSSI.
Default is 8000 ms. Range is 1–32767 ms.
Property 0x3708 FM_HIBLEND_MULTIPATH_THRESHOLDS
The FM_HIBLEND_MULTIPATH_THRESHOLDS property sets the Multipath thresholds for Hi-blend to begin band
limiting and reach maximum band limiting on L-R channel based on max and min cutoff frequencies (set by
Property 0x3709) on the Hi-blend engine. The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 0x193C
FM_HIBLEND_MULTIPATH_THRESHOLDS
15
14
Bit
128
13
12
11
10
9
8
7
6
5
4
3
MULTMIN[7:0]
MULTMAX[7:0]
0x19
0x3C
2
1
0
Name
Function
15:8
MULTMIN[7:0]
Sets the Multipath level at which Hi-cut reaches max band limiting on the LR channel based on cutoff frequency set by property 0x3709.
Default is 25. Range is 0–127%.
7:0
MULTMAX[7:0]
Sets the Multipath level at which Hi-blend begins to band limit on the L-R
channel based on cutoff frequency set by property 0x3709.
Default is 60. Range is 0–127%.
Rev. 0.3
AN645
Property 0x3709 FM_HIBLEND_MULTIPATH_CUTOFF_FREQ
The FM_HIBLEND_MULTIPATH_CUTOFF_FREQ property sets the maximum and minimum cutoff frequency
based on Multipath (set by Property 0x3708) on the Hi-blend engine. You can force a constant cutoff frequency
value by setting FREQ_MAX and FREQ_MIN to the same value. To disable the Hi-blend based on Multipath, set
FREQ_MAX = FREQ_MIN = 180 (0xB4.) The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 0xB41E
Units: 100 Hz
FM_HIBLEND_MULTIPATH_CUTOFF_FREQ
15
14
13
12
11
10
9
8
7
6
5
4
3
FREQ_MAX[7:0]
FREQ_MIN[7:0]
0xB4
0x1E
2
1
0
Bit
Name
Function
15:8
FREQ_MAX[7:0]
Sets the maximum cutoff frequency. Default is 18 kHz. Range is 0–18 kHz.
7:0
FREQ_MIN[7:0]
Sets the minimum stereo separation. Default is 3 kHz. Range is 0–18 kHz.
Property 0x370A FM_HIBLEND_MULTIPATH_ATTACK_TIME
The FM_HIBLEND_MULTIPATH_ATTACK_TIME property sets the transition time for which the Hi-blend mitigation
engine lowers the cutoff frequency based on Multipath. The CTS bit (and optional interrupt) is set when it is safe to
send the next command. This property may only be set or read in powerup mode.
Default: 4
Units: ms
FM_HIBLEND_MULTIPATH_ATTACK_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK[15:0]
0x0004
Bit
Name
Function
15:0
ATTACK[15:0]
Sets the transition time for which the Hi-blend mitigation engine decreases
the cutoff frequency based on Multipath.
Default is 4 ms. Range is 1–32767 ms.
Rev. 0.3
129
AN645
Property 0x370B FM_HIBLEND_MULTIPATH_RELEASE_TIME
The FM_HIBLEND_MULTIPATH_RELEASE_TIME property sets the transition time for which the Hi-blend
mitigation engine increases the cutoff frequency based on RSSI. The CTS bit (and optional interrupt) is set when it
is safe to send the next command. This property may only be set or read in powerup mode.
Default: 8000
Units: ms
FM_HIBLEND_MULTIPATH_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x1F40
Bit
Name
Function
15:0
RELEASE[15:0]
Sets the transition time for which the Hi-blend mitigation engine increases
the cutoff frequency based on Multipath.
Default is 8000 ms. Range is 1–32767 ms.
Property 0x3710 FM_HIBLEND_USN_THRESHOLDS
The FM_HIBLEND_USN_THRESHOLDS property sets the USN thresholds for Hi-blend to begin band limiting and
reach maximum band limiting on L-R channel based on max and min cutoff frequencies (set by Property 0x3711)
on the Hi-blend engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
property may only be set or read in powerup mode.
Default: 0x371E
Units: –dBFS
FM_HIBLEND_USN_THRESHOLDS
15
14
12
11
10
9
8
7
6
5
4
3
USNMIN[7:0]
USNMAX[7:0]
0x37
0x1E
2
1
0
Bit
Name
Function
15:8
USNMIN[7:0]
Sets the USN level at which Hi-blend reaches max band limiting on the L-R
channel based on cutoff frequency set by property 0x3711.
Default is –55 dBFS. Range is 0–127 –dBFS.
USNMAX[7:0]
Sets the Multipath level at which Hi-blend begins to band limit on the L-R
channel based on cutoff frequency set by property 0x3711.
Default is –30 dBFS. Range is 0–127 –dBFS.
7:0
130
13
Rev. 0.3
AN645
Property 0x3711 FM_HIBLEND_USN_CUTOFF_FREQ
The FM_HIBLEND_USN_CUTOFF_FREQ property sets the maximum and minimum cutoff frequency based on
USN (set by Property 0x3710) on the Hi-blend engine. You can force a constant cutoff frequency value by setting
FREQ_MAX and FREQ_MIN to the same value. To disable the Hi-blend based on USN, set
FREQ_MAX = FREQ_MIN = 180 (0xB4.) The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 0xB41E
Units: 100 Hz
FM_HIBLEND_USN_CUTOFF_FREQ
15
14
13
12
11
10
9
8
7
6
5
4
3
FREQ_MAX[7:0]
FREQ_MIN[7:0]
0xB4
0x1E
2
1
0
Bit
Name
Function
15:8
FREQ_MAX[7:0]
Sets the maximum cutoff frequency. Default is 18 kHz. Range is 0–18 kHz.
7:0
FREQ_MIN[7:0]
Sets the minimum stereo separation. Default is 3 kHz. Range is 0–18 kHz.
Property 0x3712 FM_HIBLEND_USN_ATTACK_TIME
The FM_HIBLEND_USN_ATTACK_TIME property sets the transition time for which the Hi-blend mitigation engine
lowers the cutoff frequency based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read in powerup mode.
Default: 4
Units: ms
FM_HIBLEND_USN_ATTACK_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK[15:0]
0x0004
Bit
Name
Function
15:0
ATTACK[15:0]
Sets the transition time for which the Hi-blend mitigation engine lowers the
cutoff frequency based on USN.
Default is 4 ms. Range is 1–32767 ms.
Rev. 0.3
131
AN645
Property 0x3713 FM_HIBLEND_USN_RELEASE_TIME
The FM_HIBLEND_USN_RELEASE_TIME property sets the transition time for which the Hi-blend mitigation
engine increases the cutoff frequency based on USN. The CTS bit (and optional interrupt) is set when it is safe to
send the next command. This property may only be set or read in powerup mode.
Default: 8000
Units: ms
FM_HIBLEND_USN_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x1F40
132
Bit
Name
15:0
RELEASE[15:0]
Function
Sets the transition time for which the Hi-blend mitigation engine increases
the cutoff frequency based on USN.
Default is 8000 ms. Range is 1–32767 ms.
Rev. 0.3
AN645
Property 0x4000 FM_RDS_INTERRUPT_SOURCE
The FM_RDS_INTERRUPT_SOURCE property configures interrupt related to RDS. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
FM_RDS_INTERRUPT_SOURCE
15
14
13
12
11
10
9
8
7
6
5
0x000
4
RDSTPPTY RDSPI
0x000
Bit
Name
15:5
Reserved
3
0
0
2
1
0
0
RDSSYNC
RDSRECV
0
0
0
Function
Always write 0.
RDSTPPTY
If set, generates RDS Interrupt when first valid Block B data has been
received or if Block B data is different from last valid Block B data.
0 = Disabled.
1 = Enabled.
3
RDSPI
If set, generates RDS Interrupt when first valid Block A data has been
received or if Block A data is different from last valid Block A data.
0 = Disabled.
1 = Enabled.
2
Reserved
4
1
0
Always write 0.
RDSSYNC
If set, generates RDS interrupt when RDS Synchronization status
changes. Default is 0.
0 = Disabled.
1 = Enabled.
RDSRECV
If set, generate an interrupt whenever the RDS FIFO has at least
FM_RDS_INTERRUPT_FIFO_COUNT entries. Default is 0
0 = Disabled.
1 = Enabled.
Rev. 0.3
133
AN645
Property 0x4001 FM_RDS_INTERRUPT_FIFO_COUNT
The FM_RDS_INTERRUPT_FIFO_COUNT property sets the minimum number of RDS groups stored in the RDS
FIFO before RDSRECV is set. RDSRECV is disabled if set to 0. The CTS bit (and optional interrupt) is set when it
is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0
FM_RDS_INTERRUPT_FIFO_COUNT
15
134
14
13
12
11
10
9
8
7
6
5
4
3
0x00
DEPTH[7:0]
0x00
0x00
Bit
Name
15:8
Reserved
7:0
DEPTH[7:0]
2
1
Function
Always write 0.
Sets the minimum number of RDS Groups stored in the RDS FIFO
required before RDSRECV is set. RDSRECV is disabled if set to 0.
Default is 0. Range is 0–25
Rev. 0.3
0
AN645
Property 0x4002 FM_RDS_CONFIG
The FM_RDS_CONFIG property configures RDS settings to enable RDS processing (RDSEN) and set RDS block
error thresholds. When a RDS Group is received, all block errors must be less than or equal to the associated
block error threshold for the group to be stored in the RDS FIFO. If blocks with errors are permitted into the FIFO,
the block error information can be reviewed when the group is read using the FM_RDS_STATUS command. The
CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or
read in powerup mode.
Default: 0x0000
FM_RDS_CONFIG
15
14
13
12
11
10
9
8
0x00
Name
15:8
Reserved
7:6
BLETHB[1:0]
5:4
BLETHCD[1:0]
3:1
Reserved
0
RDSEN
6
5
4
BLETHB[1:0] BLETHCD[1:0]
0x00
Bit
7
0x0
0x0
3
2
1
0
0x0
RDSEN
0x0
0
Function
Always write 0.
Block Error Threshold BLOCKB. Block B is most critical because it tells what C
and D contain.
0 = No errors.
1 = 1–2 bit errors detected and corrected.
2 = 3–5 bit errors detected and corrected.
3 = Uncorrectable.
Block Error Threshold for BLOCKC and BLOCKD.
0 = No errors.
1 = 1–2 bit errors detected and corrected.
2 = 3–5 bit errors detected and corrected.
3 = Uncorrectable.
Always write 0.
Enables RDS processing. Default is 0.
0 = RDS Disabled.
1 = RDS Enabled.
Rev. 0.3
135
AN645
Property 0x4003 FM_RDS_CONFIDENCE
The FM_RDS_CONFIDENCE property sets the required receiver confidence level for each RDS block prior to
demodulation. A higher confidence requirement will result in more block errors (higher percentage of blocks with
BLE=3), but reduces the chance of decoder errors (lower percentage of blocks that contain incorrect information
despite having BLE<3). Higher confidence requirements may result in a decrease in the frequency with which RDS
data is stored in the FIFO. Higher block error rates will affect RDS sensitivity tests. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read when in the
powerup mode.
Default: 0x1111
FM_RDS_CONFIDENCE
15
14
12
11
10
9
8
7
6
5
4
3
2
1
0
CONFIDENCEA[3:0]
CONFIDENCEB[3:0]
CONFIDENCEC[3:0]
CONFIDENCED[3:0]
0x1
0x1
0x1
0x1
Bit
15:12
11:8
7:4
3:0
136
13
Name
Function
CONFIDENCEA[3:0]
Sets the decoder error rate threshold for BLOCK A.
0 = Reserved.
1 = Lowest confidence required. A valid and usable confidence threshold.
2–14 = Medium confidence required. High value may result in all blocks
being marked as uncorrectable.
15 = Highest confidence required. This setting may result in all blocks being
marked as uncorrectable.
CONFIDENCEB[3:0]
Sets the decoder error rate threshold for BLOCK B.
0 = Reserved.
1 = Lowest confidence required. A valid and usable confidence threshold.
2–14 = Medium confidence required. High value may result in all blocks
being marked as uncorrectable.
15 = Highest confidence required. This setting may result in all blocks being
marked as uncorrectable.
CONFIDENCEC[3:0]
Sets the decoder error rate threshold for BLOCK C.
0 = Reserved.
1 = Lowest confidence required. A valid and usable confidence threshold.
2–14 = Medium confidence required. High value may result in all blocks
being marked as uncorrectable.
15 = Highest confidence required. This setting may result in all blocks being
marked as uncorrectable.
CONFIDENCED[3:0]
Sets the decoder error rate threshold for BLOCK D.
0 = Reserved.
1 = Lowest confidence required. A valid and usable confidence threshold.
2–14 = Medium confidence required. High value may result in all blocks
being marked as uncorrectable.
15 = Highest confidence required. This setting may result in all blocks being
marked as uncorrectable.
Rev. 0.3
AN645
9.3. Commands and Properties for AM Receiver
Table 16. AM Receiver Command Summary
Number
Name
Summary
0x40
AM_TUNE_FREQ
Tunes the AM receiver to a frequency in 1 kHz steps.
0x41
AM_SEEK_START
Initiates a seek for a channel that meets the validation criteria for AM.
0x42
AM_RSQ_STATUS
Returns status information about the received signal quality.
0x45
AM_ACF_STATUS
Returns status information about automatically controlled features.
0x47
AM_AGC_STATUS
Reports the status of AM AGC.
Table 17. AM Receiver Property Summary
Number
Name
Default
0x0400
AM_SOFT_MUTE_MAX_ATTENUATION
0x0401
AM_SOFT_MUTE_TRIGGER_THRESHOLD
0x0402
AM_SOFT_MUTE_END_THRESHOLD
0x0000 Sets the SNR threshold where soft mute will
stop attenuating.
0
0x0403
AM_SOFT_MUTE_RELEASE_TIME
0x01F4 Sets the maximum soft mute release time in
ms.
500
0x0404
AM_SOFT_MUTE_ATTACK_TIME
0x0500
AVC_MIN_GAIN
0xF800 Sets the minimum gain for automatic volume
–2048 control.
0x0501
AVC_MAX_GAIN
0x27EC Sets the maximum gain for automatic volume
10220 control.
0x0700
AM_FE_AGC_CONFIG
0xF018 Specifies the input path for the RF signal and
61464 other front-end configuration options.
0x0708
AM_IF_AGC_ATTACK_MS
0x0050 Sets the number of milliseconds the IF high
peak detector must be exceeded before atten80
uating the appropriate block.
0x0709
AM_IF_AGC_RELEASE_MS
0x000C
12
0x0008
8
Summary
Sets the maximum soft mute attenuation.
Sets the SNR threshold for soft mute to start.
0x0078 Sets the maximum soft mute attack time in
ms.
120
0x342
804
Rev. 0.3
Sets the number of milliseconds the IF low
peak detector must not be exceeded before
increasing the gain of the appropriate block
137
AN645
Table 17. AM Receiver Property Summary (Continued)
Number
0x070C
Name
AM_RF_AGC_ATTACK_MS
Default
Summary
0x0008 Sets the number of milliseconds the wideband RF high-peak detector must be
exceeded before attenuating the appropriate
8
block.
0x0320 Sets the number of milliseconds the wideband RF low-peak detector must not be
exceeded before increasing the gain of the
800
appropriate block.
0x070D
AM_RF_AGC_RELEASE_MS
0x070E
AM_LNA_PD_THRESHOLD
0x5104 Sets the high threshold and hysteresis for the
20740 LNA peak detector.
0x1100
AM_SEEK_BAND_BOTTOM
0x0208 Sets the lower seek boundary of the AM band
in multiples of 1 kHz.
520
0x1101
AM_SEEK_BAND_TOP
0x1102
AM_SEEK_FREQUENCY_SPACING
0x000A Sets the frequency spacing for the AM band in
multiples of 1 kHz when performing a seek.
10
0x1200
AM_RSQ_INTERRUPT_SOURCE
0x0000 Configures interrupt related to Received Signal Quality metrics (AM_RSQ_STATUS).
0
0x1201
AM_RSQ_SNR_HIGH_THRESHOLD
0x007F Sets high threshold, which triggers the RSQ
interrupt if the SNR is above this threshold.
127
0x1202
AM_RSQ_SNR_LOW_THRESHOLD
0xFF80 Sets low threshold, which triggers the RSQ
–128 interrupt if the SNR is below this threshold.
0x1203
AM_RSQ_RSSI_HIGH_THRESHOLD
0x007F Sets high threshold, which triggers the RSQ
interrupt if the RSSI is above this threshold.
127
0x1204
AM_RSQ_RSSI_LOW_THRESHOLD
0xFF80 Sets low threshold, which triggers the RSQ
–128 interrupt if the RSSI is below this threshold.
0x1300
AM_ACF_INTERRUPT_SOURCE
0x1301
AM_ACF_SM_THRESHOLD
138
0x06AE Sets the upper seek boundary for the AM
1710 band in multiples of 1 kHz.
0x0000
0
0x001F
31
Rev. 0.3
Enables the ACF interrupt sources.
Sets the softmute interrupt threshold in dB.
AN645
Table 17. AM Receiver Property Summary (Continued)
Number
Name
Default
Summary
0x1302
AM_ACF_CHBW_THRESHOLD
0x0000 Sets the Channel Filter Bandwidth interrupt
threshold in units of 100 Hz.
0
0x1303
AM_ACF_HICUT _THRESHOLD
0x0000 Sets the Hi-cut interrupt threshold in units of
100 Hz.
0
0x1306
AM_ACF_CONTROL_SOURCE
0x0000 Determines if SNR or RSSI will be used as the
controlling metric for ACF features.
0
0x2000
AM_VALID_MAX_TUNE_ERROR
0x2003
AM_VALID_SNR_THRESHOLD
0x0005 Sets the SNR threshold for a valid AM Seek/
Tune.
5
0x2004
AM_VALID_RSSI_THRESHOLD
0x000A Sets the RSSI threshold for a valid AM Seek/
Tune.
10
0x2200
AM_CHBW_SQ_MIN_MAX
0x2314 Sets the maximum and minimum channel BW
as determined by SNR/RSSI in units of
8980 100 Hz.
0x2201
AM_CHBW_SQ_HIGH_THRESHOLD
0x001E Sets the SNR/RSSI threshold for maximum
channel filter bandwidth.
30
0x2202
AM_CHBW_SQ_LOW_THRESHOLD
0x000F Sets the SNR/RSSI threshold for minimum
channel filter bandwidth.
15
0x2203
AM_CHBW_SQ_WIDENING_TIME
0x0800 Sets the channel filter bandwidth widening
2048 time based on SNR/RSSI in units of ms.
0x2204
AM_CHBW_SQ_NARROWING_TIME
0x0010 Sets the channel filter bandwidth narrowing
time based on SNR/RSSI in units of ms.
16
0x2205
AM_CHBW_ASSI_MIN_MAX
0x3232 Sets the maximum and minimum channel BW
12850 as determined by ASSI in units of 100 Hz.
0x2206
AM_CHBW_ASSI_LOW_THRESHOLD
0x000A Sets the ASSI threshold for maximum channel
filter bandwidth.
10
0x2207
AM_CHBW_ASSI_HIGH_THRESHOLD
0x001E Sets the ASSI threshold for minimum channel
filter bandwidth.
30
0x004B Sets the maximum frequency error allowed
before setting the AFCRL indicator.
75
Rev. 0.3
139
AN645
Table 17. AM Receiver Property Summary (Continued)
Number
Name
0x2208
AM_CHBW_ASSI_WIDENING_TIME
0x0010 Sets the channel filter bandwidth widening
time based on ASSI in units of ms.
16
0x2209
AM_CHBW_ASSI_NARROWING_TIME
0x0010 Sets the channel filter bandwidth narrowing
time based on ASSI in units of ms.
16
0x3100
AM_HICUT_SQ_HIGH_THRESHOLD
0x0008 Sets the SNR/RSSI based Hi-cut high SNR/
RSSI threshold.
8
0x3101
AM_HICUT_SQ_LOW_THRESHOLD
0x0000 Sets the SNR/RSSI based Hi-cut low SNR/
RSSI threshold.
0
0x3102
AM_HICUT_ATTACK_TIME
0x0010 Sets the Hi-cut cutoff frequency attack time in
ms.
16
0x3103
AM_HICUT_RELEASE_TIME
0x07D0 Sets the Hi-cut cutoff frequency release time
2000 in ms.
0x3104
AM_HICUT_CUTOFF_FREQ
0x280A Sets the Hi-cut Cutoff Max and Min audio fre10250 quencies.
0x3105
AM_LOWCUT_MIN_FREQ
0x3106
AM_LOWCUT_MAX_FREQ
0x3300
AM_IBOC_CONTROL
0x3301
AM_IBOC_ANALOG_TO_HD_
CROSSFADE_TIME
0x03E8 Sets the crossfade time between full analog
and full HD Digital audio in ms
1000 (Si4777 only).
0x3302
AM_IBOC_HD_TO_ANALOG_
CROSSFADE_TIME
0x03E8 Sets the crossfade time from full HD Digital to
1000 full analog audio in ms (Si4777 only).
0x3303
AM_IBOC_DYNAMIC_GAIN
0x007F Sets the digital audio dynamic linear scaling
factor (Si4777 only).
127
0x3304
AM_IBOC_STATIC_GAIN
0x0100 Sets the digital audio static linear gain factor
(Si4777 only).
256
140
Default
0x0000
0
0x0000
0
Summary
Sets the minimum LowCut cutoff frequency.
Sets the maximum LowCut cutoff frequency.
0x0000 Control property for IBOC Blend
(Si4777 only).
0
Rev. 0.3
AN645
9.3.1. AM Receiver Commands
Command 0x40 AM_TUNE_FREQ
The AM_TUNE_FREQ command sets the AM Receiver to tune to a frequency in 1 kHz units. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. The ERR bit (and optional interrupt) is set if an
invalid argument is sent. Note that only a single interrupt occurs if both the CTS and ERR bits are set. The optional
STC interrupt is set when the command completes. This command may only be sent in powerup mode. The
command clears the STC bit if it is already set.
Command
Bit
7
6
5
4
3
1
0
0x40
CMD
ARG1
2
0
0
ZIFSR
ARG2
FREQH[7:0]
ARG3
FREQL[7:0]
ARG4
ANTCAPH[7:0]
ARG5
ANTCAPL[7:0]
Rev. 0.3
141
AN645
ARG
Bit
Name
1
7
Reserved
1
6
ZIFSR
1
5:0
Reserved
2
7:0
3
7:0
4
7:0
5
7:0
Function
Always write 0.
Sets the ZIP sample rate.
ZIFSR=0, low ZIF sample rate (40.625,
42.1875, or 46.5117 kHz, depending on crystal frequency)
ZIFSR=1, high ZIF sample rate (650, 675, or
744.1875 kHz, depending on crystal frequency)
See section “7. Digital ZIF I/Q Interface”.
Always write 0.
FREQH[7:0]
Tune Frequency High Byte.
This byte in combination with FREQL selects
the tune frequency in units of 1 kHz. Valid
range is from 520 to 1710 (520–1710 kHz).
FREQL[7:0]
Tune Frequency Low Byte.
This byte in combination with FREQH selects
the tune frequency in units of 1 kHz. Valid
range is from 520 to 1710 (520–1710 kHz).
ANTCAPH[7:0]
Antenna Tuning Capacitor High Byte.
This byte, in combination with ANTCAPL[7:0],
sets the antenna tuning capacitor value in 92
fF increments. Max value is 580 pF. Range is
1-6304. Setting ANTCAP to 0 automatically
determines the capacitor value.
ANTCAPL[7:0]
Antenna Tuning Capacitor Low Byte.
This byte, in combination with ANTCAPH[7:0],
sets the antenna tuning capacitor value in 92
fF increments. Max value is 580 pF. Range is
1-6304. Setting ANTCAP to 0 automatically
determines the capacitor value.
Response
Bit
7
6
STATUS
CTS
ERR
142
5
4
XX
Rev. 0.3
3
2
1
0
RSQINT
X
ACFINT
STCINT
AN645
Command 0x41 AM_SEEK_START
The AM_SEEK_START command begins searching for a valid frequency. In order for a station to be considered
valid,
each
of
the
following
thresholds
must
be
met:
AM_VALID_SNR_THRESHOLD,
AM_VALID_RSSI_THRESHOLD, and AM_VALID_MAX_TUNE_ERROR. Clears any pending STCINT or RSQINT
interrupt status. Seek can be cancelled through setting the CANCEL bit in the AM_RSQ_STATUS command. The
CTS bit (and optional interrupt) is set when it is safe to send the next command. RSQINT status is only cleared by
the AM_RSQ_STATUS command when the RSQACK bit is set. The ERR bit (and optional interrupt) is set if an
invalid argument is sent. Note that only a single interrupt occurs if both the CTS and ERR bits are set. The optional
STC interrupt is set when the command completes. This command may only be sent in powerup mode. The
command clears the STCINT bit if it is already set.
Command
Bit
7
6
5
4
3
2
SEEKUP
WRAP
1
0
0x41
CMD
0000
ARG1
ARG
Bit
Name
1
7:4
Reserved
00
Function
Always write 0.
Wrap/Halt.
Determines whether the seek should Wrap = 1, or Halt = 0 when
it hits the band limit.
1
3
WRAP
1
2
SEEKUP
Seek Up/Down.
Determines the direction of the search, either UP = 1, or
DOWN = 0.
1
1:0
Reserved
Always write 0.
Response
Bit
7
6
STATUS
CTS
ERR
5
4
XX
Rev. 0.3
3
2
1
0
RSQINT
X
ACFINT
STCINT
143
AN645
Command 0x42 AM_RSQ_STATUS
The AM_RSQ_STATUS command returns status information about the received signal quality. This command
returns Received Signal Strength Indicator (RSSI), Signal to Noise Ratio (SNR), High Side Adjacent Channel
Strength (HASSI), Low Side Adjacent Channel Strength (LASSI), Frequency Offset (FREQOFF), and AM
Modulation Index (MOD) associated with the desired channel. It also indicates valid channel (VALID) and AFC rail
status (AFCRL). This command can be used to check if the received signal is above the RSSI high threshold as
reported by RSSIHINT, or below the RSSI low threshold as reported by RSSILINT. It can also be used to check if
the signal is above the SNR high threshold as reported by SNRHINT, or below the SNR low threshold as reported
by SNRLINT.
The command clears the RSQINT, SNRHINT, SNRLINT, RSSIHINT and RSSILINT interrupt bits when RSQACK bit
of ARG1 is set. If the condition is still true after the interrupt is cleared another interrupt will fire assuming that bit is
enabled in AM_RSQ_INTERRUPT_SOURCE. The CTS bit (and optional interrupt) is set when it is safe to send
the next command. This command may only be sent in powerup mode.
Command
Bit
7
6
5
4
2
1
0
RSQACK
ATTUNE
CANCEL
STCACK
0x42
CMD
0000
ARG1
ARG
Bit
Name
1
7:4
Reserved
Always write 0.
1
3
RSQACK
Clears RSQINT, SNRHINT, SNRLINT, RSSIHINT, RSSILINT if
set.
ATTUNE
Returns the values of metrics as of tune time. When the
AT_TUNE bit is set, values returned for RSQ_STATUS are the
values calculated at tune and do not change unless another
TUNE_FREQ command is called. This feature can be used to
determine why seek stopped at the current station.
1
144
3
2
Function
1
1
CANCEL
Aborts a seek or tune currently in progress
0 = Don't abort.
1 = Abort.
1
0
STCACK
Clears the STC interrupt status indicator if set.
Rev. 0.3
AN645
Response
Bit
7
6
5
STATUS
CTS
ERR
RESP1
X
X
X
RESP 2
BLTF
X
SNRREADY
4
3
2
1
0
RSQINT
X
ACFINT
STCINT
X
SNRHINT
SNRLINT
RSSIHINT
RSSILINT
RSSIREA
DY
X
X
AFCRL
VALID
XX
RESP 3
READFREQ[15:8]
RESP 4
READFREQ[7:0]
RESP 5
FREQOFF[7:0]
RESP 6
RSSI[7:0]
RESP 7
SNR[7:0]
RESP 8
XXXXXXXX
RESP 9
LASSI[7:0]
RESP 10
HASSI[7:0]
RESP 11
XXXXXXXX
RESP 12
MOD[7:0]
RESP 13
ANTCAPH[7:0]
RESP 14
ANTCAPL[7:0]
Rev. 0.3
145
AN645
RESP
Bit
Name
1
7:4
Reserved
Values may vary.
1
3
SNRHINT
SNR Detect High
0 = Received SNR has not exceeded above SNR
programmed using
AM_RSQ_SNR_HIGH_THRESHOLD.
1 = Received SNR has exceeded above SNR
threshold programmed using
AM_RSQ_SNR_HIGH_THRESHOLD.
SNRLINT
SNR Detect Low
0 = Received SNR has not fallen below SNR threshold
programmed using
AM_RSQ_SNR_LOW_THRESHOLD.
1 = Received SNR has fallen below SNR threshold
programmed using
AM_RSQ_SNR_LOW_THRESHOLD.
RSSIHINT
RSSI Detect High
0 = RSSI has not exceeded above RSSI threshold
programmed using
AM_RSQ_RSSI_HIGH_THRESHOLD.
1 = RSSI has exceeded above RSSI threshold
programmed using
AM_RSQ_RSSI_HIGH_THRESHOLD.
RSSILINT
RSSI Detect Low
0 = RSSI has not fallen below RSSI threshold.
programmed using
AM_RSQ_RSSI_LOW_THRESHOLD.
1 = RSSI has fallen below RSSI threshold programmed
using AM_RSQ_RSSI_LOW_THRESHOLD.
Band Limit
Reports if a seek hit the band limit (WRAP = 0 in AM_SEEK_START) or wrapped to the original frequency
(WRAP = 1).
1
1
1
146
2
1
0
2
7
BLTF
2
6
Reserved
Function
Values may vary.
Rev. 0.3
AN645
RESP
2
Bit
5
Name
Function
SNRREADY
SNR Status
When set, indicates that the SNR metric was read as
part of a tune. If this flag is not set once tune completes,
the SNR metric was not measured. A metric not measured indicates that a tune was terminated prematurely
due to an invalidating condition (i.e., RSSI did not meet
the minimum threshold).In this case, tune time RSQ will
report 0 for SNR. The normal running SNR is not
affected by this flag.
0 = SNR measurement in progress (tune in progress).
1 = SNR measurement ready or not taken (tune completed).
RSSI Status
When set, indicates that the RSSI metric was read as
part of a tune. If this flag is not set once tune completes,
the RSSI metric was not measured. A metric not measured indicates that a tune was terminated prematurely
due to an invalidating condition (i.e., RSSI did not meet
the minimum threshold).In this case, tune time RSQ will
report 0 for RSSI. The normal running RSSI is not
affected by this flag.
0 = RSSI measurement in progress (tune in progress).
1 = RSSI measurement ready or not taken (tune completed).
2
4
RSSIREADY
2
3:2
Reserved
2
1
AFCRL
Set if the AFC rails (AFC gets railed if FREQOFF >
MAX_TUNE_ERROR).
2
0
VALID
Reports if the channel is valid based on the settings of
AM_VALID_RSSI_THRESHOLD, AM_VALID_SNR_THRESHOLD, AM_VALID_MAX_TUNE_ERROR.
3,4
15:0
READFREQ[15:0]
5
7:0
FREQOFF[7:0]
6
7:0
RSSI[7:0]
Received Signal Strength indicator in dBµV
(–128 to 127).
7
7:0
SNR[7:0]
RF SNR indicator in dB (–128 to 127).
8
7:0
Reserved
Values may vary
9
7:0
LASSI[7:0]
Low Side Adjacent Channel Strength Indicator reports
the Signal + Noise power relative to the carrier.
(–128 to 127).
10
7:0
HASSI[7:0]
High Side Adjacent Channel Strength Indicator reports
the Signal + Noise power relative to the carrier.
(–128 to 127).
11
7:0
Reserved
Values may vary.
12
7:0
MOD[7:0]
AM Modulation Index in percent range 0–100.
Values may vary
Returns the currently tuned frequency.
Frequency offset in units of 2 ppm (–128 to 127).
Rev. 0.3
147
AN645
RESP
13
14
148
Bit
7:0
7:0
Name
Function
ANTCAPH[7:0]
Antenna Tuning Capacitor High Byte.
This byte, in combination with ANTCAPL[7:0], reports
the antenna tuning capacitor value in 92 fF increments.
Max value is 580 pF. Range is 1-6304.
ANTCAPL[7:0]
Antenna Tuning Capacitor High Byte.
This byte, in combination with ANTCAPH[7:0], reports
the antenna tuning capacitor value in 92 fF increments.
Max value is 580 pF. Range is 1-6304.
Rev. 0.3
AN645
Command 0x45 AM_ACF_STATUS
The AM_ACF_STATUS command returns status information about automatically controlled features. This
command returns the Soft Mute Attenuation, Channel Filter Bandwidth, and Hi-cut cutoff frequency associated with
the desired channel. If SMUTE bit is high it indicates that is audio is soft muted. The CTS bit (and optional interrupt)
is set when it is safe to send the next command. This command may only be sent in powerup mode.
Command
Bit
7
6
5
4
3
2
1
0
0x45
CMD
0
ARG1
ACFACK
ARG
Bit
Name
Function
1
7:1
Reserved
Always write 0.
1
0
ACFACK
If set to 1, clears ACFINT and any ACF interrupt bits.
Response
Bit
7
6
STATUS
CTS
ERR
4
XX
3
2
1
0
RSQINT
X
ACFINT
STCINT
HICUT_INT
CHBW_INT
SOFTMUTE_INT
XXX XXXX
RESP1
XXXXXXX
RESP2
RESP3
5
XXX
SMUTE
SMATTN[4:0]
RESP4
CHANBW[7:0]
RESP5
HICUT [7:0]
Rev. 0.3
149
AN645
RESP
Bit
Name
1
7:3
Reserved
1
2
HICUT_INT
Indicates that Hi-cut cutoff frequency has crossed below the
Hi-cut threshold set by AM_ACF_HICUT_THRESHOLD.
1
1
CHBW_INT
Indicates that channel filter bandwidth is less than the threshold set by ACF_CHBW_THRESHOLD.
1
0
SOFTMUTE_INT
2
7:1
Reserved
2
0
SMUTE
3
7:5
Reserved
3
4:0
SMATTN[4:0]
Soft mute attenuation level in dB.
Range: 0–31.
4
7:0
CHANBW[7:0]
Channel filter bandwidth in 100 Hz.
Range: 0–150.
5
7:0
HICUT [7:0]
150
Function
Values may vary.
Indicates that SM attenuation has increased above
ACF_SM_THRESHOLD.
Values may vary.
0 = Audio is not soft muted.
1 = Audio is soft muted.
Values may vary.
Hi-cut cutoff frequency in units of 100 Hz.
Range: 10–50.
Rev. 0.3
AN645
Command 0x47 AM_AGC_STATUS
The AM_AGC_STATUS command reports the current status of the AM AGC. The command is complete when the
CTS bit (and optional interrupt) is set. This command may only be sent in powerup mode.
Command
Bit
7
6
5
4
3
2
1
0
3
2
1
0
RSQINT
X
ACFINT
STCINT
AMHI
AMLO
0x47
CMD
Response
Bit
7
6
Status
CTS
ERR
5
4
XX
XXXXXX
RESP1
RESP 2
XX
RESP 3
XX
RESP 4
PGAGAIN[7:0]
RESP 5
RFATTN[7:0]
RESP
Bit
Name
1
7:2
Reserved
1
1
AMHI
0 = AM LNA PD high threshold is not tripped.
1 = AM LNA PD high threshold is tripped.
1
0
AMLO
0 = AM LNA PD low threshold is not tripped.
1 = AM LNA PD low threshold is tripped.
2
7:0
Reserved
Values may vary.
3
7:0
Reserved
Values may vary.
4
7:0
5
7:0
Function
Values may vary.
PGAGAIN[7:0] PGA gain in dB.
AM loop resistive attenuation index.
Range: 0-63
0 = 800 Kohms ~ no attenuation
RFATTN[7:0]
1 = 0.875 * 800 k
2 = 0.875^2 * 800 k
63 = 0.875^63 * 800 k = 177 
Rev. 0.3
151
AN645
9.3.2. AM Receiver Properties
Property 0x0400 AM_SOFT_MUTE_MAX_ATTENUATION
The AM_SOFT_MUTE_MAX_ATTENUATION property sets the maximum attenuation in dB that will be applied by
the softmute feature. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
property may only be set or read in powerup mode.
Default: 12
Units: dB
AM_SOFT_MUTE_MAX_ATTENUATION
15
14
13
12
11
Bit
Name
15:5
Reserved
4:0
SMATTN[4:0]
10
9
8
7
6
5
4
3
2
1
0x000
SMATTN[4:0]
0x000
0x0C
0
Function
Always write 0.
Sets the maximum attenuation in dB that will be applied by the softmute
feature.
Default is 12 dB. Range is 0–31 dB.
Property 0x0401 AM_SOFT_MUTE_TRIGGER_THRESHOLD
The AM_SOFT_MUTE_TRIGGER_THRESHOLD property sets the SNR threshold in dB to engage softmute. The
CTS bit (and optional interrupt) is set when it is safe to send the next command. If USE_RSSI is set in
AM_ACF_CONTROL_SOURCE property, then property 0x0401 refers to RSSI threshold. This property may only
be set or read in powerup mode.
Default: 8
Units: dB
AM_SOFT_MUTE_TRIGGER_THRESHOLD
15
152
14
13
12
11
10
9
8
7
6
5
4
3
0x00
SMTRGTH[7:0]
0x00
0x08
Bit
Name
15:8
Reserved
7:0
SMTRGTH[7:0]
Function
Always write 0.
Sets the SNR threshold in dB to engage softmute.
Default is 8 dB. Range is –127 to 127 dB.
Rev. 0.3
2
1
0
AN645
Property 0x0402 AM_SOFT_MUTE_END_THRESHOLD
The AM_SOFT_MUTE_END_THRESHOLD property sets the SNR threshold in dB at which softmute attenuation
will be set to its maximum value. When the SNR is at this level or lower, the audio attenuation will be set to
AM_SOFT_MUTE_MAX_ATTENUATION. The CTS bit (and optional interrupt) is set when it is safe to send the
next command. If USE_RSSI is set in AM_ACF_CONTROL_SOURCE property, then property 0x0402 refers to
RSSI threshold. This property may only be set or read in powerup mode.
Default: 0
Units: dB
AM_SOFT_MUTE_END_THRESHOLD
15
14
13
12
10
9
8
7
6
5
4
3
0x00
SMENDTH[7:0]
0x00
0x00
Bit
Name
15:8
Reserved
7:0
11
2
1
0
Function
Always write 0.
SMENDTH[7:0]
Sets the SNR threshold in dB at which softmute attenuation will be set to its
maximum value given by
AM_SOFT_MUTE_MAX_ATTENUATION property.
Default is 0 dB. Range is –127 to 127 dB.
Property 0x0403 AM_SOFT_MUTE_RELEASE_TIME
The AM_SOFT_MUTE_RELEASE_TIME property sets the maximum time in ms it takes to unmute the audio. The
CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or
read in powerup mode.
Default: 500
Units: ms
AM_SOFT_MUTE_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x01F4
Bit
15:0
Name
RELEASE[15:0]
Function
Sets the maximum time in ms it takes to unmute the audio.
Default is 500 ms. Range is 1–32767 ms. Note that there will be 16 ms of
filter delay for the RSSI/SNR metric before softmute can engage/disengage.
Rev. 0.3
153
AN645
Property 0x0404 AM_SOFT_MUTE_ATTACK_TIME
The AM_SOFT_MUTE_ATTACK_TIME property sets the maximum time in ms it takes to mute the audio. The CTS
bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 120
Units: ms
AM_SOFT_MUTE_ATTACK_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK[15:0]
0x0078
Bit
Name
Function
Sets the maximum time in ms it takes to mute the audio.
15:0
ATTACK[15:0]
Default is 120 ms. Range is 1–32767 ms. Note that there will be 16 ms of
filter delay for the RSSI/SNR metric before softmute can engage/
disengage.
Property 0x0500 AVC_MIN_GAIN
The AVC_MIN_GAIN property sets the minimum gain for automatic volume control. The minimum gain value is
given by MINGAIN = g * 170 where g is the desired minimum AVC gain in dB. The CTS bit (and optional interrupt)
is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: –2048
AVC_MIN_GAIN
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
MINGAIN[15:0]
0xF800
Bit
Name
Function
15:0
MINGAIN[15:0]
The minimum gain value for the AVC. MINGAIN = g x 170. Range for MINGAIN is –4096 to 3061. This implies that the range of g is –24 dB to +18 dB
154
Rev. 0.3
AN645
Property 0x0501 AVC_MAX_GAIN
The AVC_MAX_GAIN property sets the maximum gain for automatic volume control. The maximum gain value is
given by MAXGAIN = g x 170 where g is the desired maximum AVC gain in dB. The CTS bit (and optional interrupt)
is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 10220
AVC_MAX_GAIN
15
14
13
12
11
10
0
9
8
7
6
5
4
3
2
1
0
MAXGAIN[14:0]
0x27EC
0
Bit
Name
15
Reserved
14:0
MAXGAIN[14:0]
Function
Always set to 0.
The maximum gain value for the AVC. MAXGAIN = g x 170. Range is 0–
32767. This implies that the range of g is 0–193 dB
Property 0x0700 AM_FE_AGC_CONFIG
Specifies the input path for the RF signal and other front-end configuration options. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. The property may only be set or read when in the
powerup mode. Changes to this property take effect after the next tune is completed.
Default: 0x14
AM_FE_AGC_CONFIG
15:12
11:8
CCL000
0
0xF000
0
7
6
FMMIX NOINTRU
0
0
5
4
3
2
1
ATTENFM
HARMREJ
INPUTSELECT[3:0]
0
1
0x8
Bit
Name
15:12
CCL
11:8
Reserved
Always write 0.
7
Reserved
Always write 0.
6
NOINTRU
0=In AM, external FM intrusion filter exists on AM antenna circuit.
1=In AM, FM attenuators are off.
5
ATTENFM
0=In AM, FM attenuators are turned on to improve FM intrusion.
1=In AM, FM attenuators are off.
4
HARMREJ
0=Harmonic reject is disabled.
1=Harmonic reject is enabled.
3:0
INPUTSELECT[3:0]
0
Function
Coupling Capacitor value at loop input. Default is 15 pF.
8=Receive signal comes into the AMIL pin (loop antenna)
Rev. 0.3
155
AN645
Property 0x0708 AM_IF_AGC_ATTACK_MS
Sets the number of milliseconds the IF high peak detector must be exceeded before attenuating the appropriate
block. The peak detectors are only sampled once every 3–5 ms. If the peak detector trips, the internal counter is
incremented by 4 ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
property may only be set or read when in the powerup mode.
Default: 80
Units: ms
AM_IF_AGC_ATTACK_MS
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
IF_AGC_ATTACK_MS[15:0]
0x0050
Bit
Name
Function
15:0
IF_AGC_ATTACK_MS[15:0]
Number of milliseconds the IF high peak detector must be exceeded
before attenuating the appropriate block. Range: 4–4096 ms.
Property 0x0709 AM_IF_AGC_RELEASE_MS
Sets the number of milliseconds the IF low peak detector must not be exceeded before increasing the gain of the
appropriate block. The peak detectors are only sampled once every 3–5 ms. If the peak detector trips, the internal
counter is incremented by 4 ms. The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read when in the powerup mode.
Default: 804
Units: ms
AM_IF_AGC_RELEASE_MS
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
IF_AGC_RELEASE_MS[15:0]
0x0324
Bit
Name
15:0
IF_AGC_RELEASE_MS[15:0]
Function
Number of milliseconds the IF low peak detector must not be
exceeded before increasing the gain of the appropriate block.
Range: 4–4096 ms.
Note: For best performance AM_IF_AGC_RELEASE_MS > AM_RF_AGC_RELEASE_MS and set
AM_IF_AGC_RELEASE_MS to 804 ms for AM_RF_AGC_RELEASE_MS of 800 ms.
156
Rev. 0.3
0
AN645
Property 0x070C AM_RF_AGC_ATTACK_MS
The AM_RF_AGC_ATTACK_MS property sets the number of milliseconds the wideband RF high-peak detector
must be exceeded before attenuating the appropriate block. The peak detectors are only sampled once every 3–
5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and optional interrupt) is
set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 8
Units: ms
AM_RF_AGC_ATTACK_MS
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RF_AGC_ATTACK_MS[15:0]
0x0008
Bit
Name
Function
15:0
RF_AGC_ATTACK_MS[7:0]
Number of milliseconds the wide-band RF high-peak detector must be exceeded before attenuating the appropriate
block. Default is 8 ms. Range is 4–4096 ms.
Property 0x070D AM_RF_AGC_RELEASE_MS
The AM_RF_AGC_RELEASE_MS property sets the number of milliseconds the wideband RF low-peak detector
must not be exceeded before increasing the gain of the appropriate block. The peak detectors are only sampled
once every 3–5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 800
Units: ms
AM_RF_AGC_RELEASE_MS
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RF_AGC_RELEASE_MS[15:0]
0x0320
Bit
Name
Function
15:0
RF_AGC_RELEASE_MS[7:0]
Number of milliseconds the wideband RF low-peak detector
must not be exceeded before increasing the gain of the appropriate block. Default is 800 ms. Range is 4–4096 ms.
Note: For best performance, AM_IF_AGC_RELEASE_MS > AM_RF_AGC_RELEASE_MS
Rev. 0.3
157
AN645
Property 0x070E AM_LNA_PD_THRESHOLD
The AM_LNA_PD_THRESHOLD property sets the high threshold and hysteresis for the LNA peak detector. The
high threshold sets the level at which the AGC increases attenuation. The hysteresis is how many dB below the
high threshold the level must drop before the AGC decreases attenuation. The CTS bit (and optional interrupt) is
set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0x5104
AM_LNA_PD_THRESHOLD
15
14
Bit
15:8
7:0
158
13
12
11
10
9
8
7
6
5
4
3
HIGH[7:0]
HYST[7:0]
0x51
0x04
Name
2
1
0
Function
HIGH[7:0]
Sets the level in dBµV at which AGC increases attenuation.
HIGH[7:0] Range: 79–93.
79 = 79 dBµV.
81 = 81 dBµV.
83 = 83 dBµV.
85 = 85 dBµV.
87 = 87 dBµV.
89 = 89 dBµV.
91 = 91 dBµV.
93 = 93 dBµV.
HYST[7:0]
Sets how many dB below the high threshold the level must drop before the AGC
decreases attenuation.
HYST[7:0] Range: 3–6.
3 = 3 dB.
4 = 4 dB.
5 = 5 dB.
6 = 6 dB.
Rev. 0.3
AN645
Property 0x1100 AM_SEEK_BAND_BOTTOM
The AM_SEEK_BAND_BOTTOM property sets the bottom of the AM band for seek. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
The default is 520 kHz.
Default: 520
Units: kHz
AM_SEEK_BAND_BOTTOM
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
AMSKFREQL[15:0]
0x0208
Bit
Name
15:0
Function
AMSKFREQL[15:0]
Sets the bottom of the AM band for seek. Default is 520 kHz.
Range: 520–1710 (MW).
144–288 (LW).
2300–30000 (SW).
Property 0x1101 AM_SEEK_BAND_TOP
The AM_SEEK_BAND_TOP property sets the top of the AM band for seek. The CTS bit (and optional interrupt) is
set when it is safe to send the next command. This property may only be set or read in powerup mode. The default
is 1710 kHz
Default: 1710
Units: kHz
15
14
13
12
11
10
AM_SEEK_BAND_TOP
9
8
7
6
AMSKFREQH[15:0]
5
4
3
2
1
0
0x06AE
Bit
15:0
Name
AMSKFREQH[15:0]
Function
Sets the top of the AM band for seek. Default is 1710 kHz.
Range: 520–1710 (MW).
144–288 (LW)
2300–30000 (SW)
Rev. 0.3
159
AN645
Property 0x1102 AM_SEEK_FREQUENCY_SPACING
The AM_SEEK_FREQUENCY_SPACING property selects frequency spacing for AM seek in multiples of 1 kHz.
The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set
or read in powerup mode. The default is 10 kHz.
Default: 10
Units: kHz
AM_SEEK_FREQUENCY_SPACING
15
14
13
12
Bit
Name
15:5
Reserved
4:0
160
11
AMSKSPACE[4:0]
10
9
8
7
6
5
4
3
2
1
0x000
AMSKSPACE[4:0]
0x000
0x0A
0
Function
Always write 0.
Selects frequency spacing for AM seek. Default is 10 kHz. Range is 1–31.
5 = SW (5 kHz).
9 = AM in Asia (9 kHz).
9 = LW (9 kHz).
10 = AM in U.S. (10 kHz).
Rev. 0.3
AN645
Property 0x1200 AM_RSQ_INTERRUPT_SOURCE
The AM_RSQ_INTERRUPT_SOURCE property configures interrupt related to Received Signal Quality metrics.
The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set
or read in powerup mode. The default is 0.
Default: 0
AM_RSQ_INTERRUPT_SOURCE
15
14
13
12
11
10
9
8
7
6
5
0x000
4
3
2
1
0
SNRHINT SNRLINT RSSIHINT RSSILINT
0x000
0
0
0
0
Bit
Name
15:4
Reserved
Always write 0.
3
SNRHINT
0: Disable Interrupt.
1: Enable interrupt to occur if SNR goes above the threshold set by AM_RSQ_SNR_HIGH_THRESHOLD.
2
SNRLINT
0: Disable Interrupt.
1: Enable interrupt to occur if SNR goes below the threshold set by AM_RSQ_SNR_LOW_THRESHOLD.
1
RSSIHINT
0: Disable Interrupt.
1: Enable interrupt to occur if RSSI goes above the threshold set by AM_RSQ_RSSI_HIGH_THRESHOLD.
RSSILINT
0: Disable Interrupt.
1: Enable interrupt to occur if RSSI goes below the threshold set by AM_RSQ_RSSI_LO_THRESHOLD.
0
Function
Rev. 0.3
161
AN645
Property 0x1201 AM_RSQ_SNR_HIGH_THRESHOLD
The AM_RSQ_SNR_HIGH_THRESHOLD property sets the high threshold, which triggers the RSQ interrupt if the
SNR is above this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command.
This property may only be set or read in powerup mode.
Default: 127
Units: dB
15
14
13
12
11
0x00
AM_RSQ_SNR_HIGH_THRESHOLD
10
9
8
7
6
5
4
3
SNRH[7:0]
0x00
Bit
Name
15:8
Reserved
7:0
SNRH [7:0]
2
1
0
0x7F
Function
Write 0 for (+) values, 0xFF for (–) values.
Sets the high threshold, which triggers the RSQ interrupt if the SNR is
above this threshold. Default is 127 dB. Range is –128 to 127 dB in steps of
1 dB.
Property 0x1202 AM_RSQ_SNR_LOW_THRESHOLD
The AM_RSQ_SNR_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if the SNR
is below this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
property may only be set or read in powerup mode.
Default: –128
Units: dB
AM_RSQ_SNR_LOW_THRESHOLD
15
14
13
12
10
9
8
7
6
5
4
3
0xFF
SNRL[7:0]
0xFF
0x80
Bit
Name
15:8
Reserved
7:0
SNRL [7:0]
162
11
2
1
0
Function
Write 0 for (+) values, 0xFF for (–) values.
Sets low threshold, which triggers the RSQ interrupt if the SNR is below this
threshold. Default is –128 dB. Range is –128 to 127 dB in steps of 1 dB.
Rev. 0.3
AN645
Property 0x1203 AM_RSQ_RSSI_HIGH_THRESHOLD
The AM_RSQ_RSSI_HIGH_THRESHOLD property sets high threshold, which triggers the RSQ interrupt if the
RSSI is above this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command.
This property may only be set or read in powerup mode.
Default: 127
Units: dBµV
AM_RSQ_RSSI_HIGH_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
0x00
RSSIH[7:0]
0x00
0x7F
Bit
Name
15:8
Reserved
7:0
RSSIH [7:0]
2
1
0
Function
Write 0 for (+) values, 0xFF for (–) values.
Sets high threshold, which triggers the RSQ interrupt if the RSSI is above
this threshold. Default is 127 dBµV. Range is –128 to 127 dBµV in steps of
1 dB.
Property 0x1204 AM_RSQ_RSSI_LOW_THRESHOLD
The AM_RSQ_RSSI_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if the RSSI
is below this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This
property may only be set or read in powerup mode.
Default: –128
Units: dBµV
15
14
13
12
11
0xFF
AM_RSQ_RSSI_LOW_THRESHOLD
10
9
8
7
6
5
4
3
RSSIL[7:0]
0xFF
Bit
Name
15:8
Reserved
7:0
RSSIL [7:0]
2
1
0
0x80
Function
Write 0 for (+) values, 0xFF for (–) values.
Sets low threshold, which triggers the RSQ interrupt if the RSSI is below this
threshold. Default is –128 dBµV. Range is –128 to 127 dBµV in steps of
1 dB.
Rev. 0.3
163
AN645
Property 0x1300 AM_ACF_INTERRUPT_SOURCE
The AM_ACF_INTERRUPT_SOURCE property enables the ACF interrupt sources. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0
AM_ACF_INTERRUPT_SOURCE
15
14
13
12
11
10
9
8
7
6
5
4
0x0000
2
1
0
HICUT_INT CHBW_INT SOFTMUTE_INT
0x0000
0
0
0
Bit
Name
15:3
Reserved
2
HICUT_INT
When set, enables the Hi-cut Interrupt. Default is 0.
0 = The Hi-cut interrupt is disabled.
1 = The Hi-cut interrupt is enabled.
1
CHBW_INT
When set, enables the Channel Filter Bandwidth Interrupt. Default is 0.
0 = The Channel Filter Bandwidth interrupt is disabled.
1 = The Channel Filter Bandwidth interrupt is enabled.
0
164
3
SOFTMUTE_INT
Function
Always write 0.
When set, enables the softmute interrupt. Default is 0.
0 = The softmute interrupt is disabled.
1 = The softmute interrupt is enabled.
Rev. 0.3
AN645
Property 0x1301 AM_ACF_SM_THRESHOLD
The AM_ACF_SM_THRESHOLD property sets the softmute interrupt threshold in dB. When softmute attenuation
rises above the level set by this property and the SOFTMUTE_INT interrupt is enabled through the
AM_ACF_INTERRUPT_SOURCE property, the SOFTMUTE_INT interrupt will be asserted. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 31
Units: dB
AM_ACF_SM_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0x000
SMATTN_THRESH[4:0]
0x000
0x1F
Bit
Name
15:5
Reserved
0
Function
Always write 0.
Softmute interrupt threshold in dB which triggers the softmute interrupt when
SMATTN_THRESH[4:0] the softmute attenuation rises above this level. Default is 31 dB.
Range is 0–31 dB.
4:0
Property 0x1302 AM_ACF_CHBW_THRESHOLD
The AM_ACF_CHBW_THRESHOLD property sets the Channel Filter Bandwidth interrupt threshold in units of
100 Hz. When the channel filter bandwidth falls below this threshold and the CHBW_INT interrupt is enabled
through the AM_ACF_INTERRUPT_SOURCE property, the CHBW_INT interrupt will be asserted. The CTS bit
(and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 0
Units: 100 Hz
AM_ACF_CHBW_THRESHOLD
15
14
13
12
10
9
8
7
6
5
4
3
2
0x00
CHBW_THRESH[7:0]
0x00
0x00
Bit
Name
15:8
Reserved
7:0
11
1
0
Function
Always write 0.
Channel Filter Bandwidth interrupt threshold in units of 100 Hz, which trigCHBW _THRESH[7:0] gers the Channel Filter Bandwidth Interrupt when the channel filter bandwidth falls below this threshold. Default is 0 kHz. Range is 0–255.
Rev. 0.3
165
AN645
Property 0x1303 AM_ACF_HICUT_THRESHOLD
The AM_ACF_HICUT_THRESHOLD property sets the Hi-cut interrupt threshold in units of 100 Hz. When the Hicut cutoff frequency falls below this threshold and the Hi-cut_INT interrupt is enabled through the
AM_ACF_INTERRUPT_SOURCE property, the Hi-cut_ INT interrupt will be asserted. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0
Units: 100 Hz
AM_ACF_HICUT_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
0x00
HICUT_THRESH[7:0]
0x00
0x00
Bit
Name
15:8
Reserved
1
0
Function
Always write 0.
Hi-cut interrupt threshold in units of 100 Hz, which triggers the Hi Cut InterHICUT_THRESH[7:0] rupt when the Hi-cut cutoff frequency falls below this threshold. Default is
0 kHz. Range is 0–200.
7:0
Property 0x1306 AM_ACF_CONTROL_SOURCE
The AM_ACF_CONTROL_SOURCE property determines if SNR or RSSI will be used as the controlling metric for
ACF features. This will affect all automatically controlled features that are controlled by SNR. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 0
AM_ACF_CONTROL_SOURCE
15
166
14
13
12
Bit
Name
15:1
Reserved
0
USE_RSSI
11
10
9
8
7
6
5
4
3
2
1
0
0x0000
USE_RSSI
0x0000
0
Function
Always write 0.
When set, RSSI will be used instead of SNR as the ACF controlling metric.
0 = Use SNR as the controlling metric.
1 = Use RSSI as the controlling metric.
Rev. 0.3
AN645
Property 0x2000 AM_VALID_MAX_TUNE_ERROR
The AM_VALID_MAX_TUNE_ERROR property sets the maximum frequency error allowed in units of 2 ppm
before setting the AFC rail indicator (AFCRL). The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read in powerup mode.
Default: 75 (150 ppm)
Units: 2 ppm
AM_VALID_MAX_TUNE_ERROR
15
14
13
12
11
10
9
8
7
6
5
4
3
2
0x00
AMMAXTUNEERR[7:0]
0x00
0x4B
Bit
Name
15:8
Reserved
7:0
AMMAXTUNEERR [7:0]
1
0
Function
Always write 0.
Sets the maximum freq error allowed in units of 2 ppm before setting the AFC
rail indicator (AFCRL). Default is 75. Range is 0–126.
Property 0x2003 AM_VALID_SNR_THRESHOLD
The AM_VALID_SNR_THRESHOLD property sets the SNR threshold for a valid AM Seek/Tune. If the desired
channel SNR is above this threshold, then it is considered valid. The CTS bit (and optional interrupt) is set when it
is safe to send the next command. This property may only be set or read in powerup mode.
Default: 5
Units: dB
AM_VALID_SNR_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
0x00
AMVALSNR[7:0]
0x00
0x05
Bit
Name
15:8
Reserved
7:0
AMVALSNR [7:0]
2
1
0
Function
Write 0 for (+) values, 0xFF for (–) values.
Sets the SNR threshold for a valid AM Seek/Tune. Default is 5 dB. Range is
–128 to 127 in steps of 1 dB.
–128 = SNR is not used as a criterion in determining the validity of a station.
Rev. 0.3
167
AN645
Property 0x2004 AM_VALID_RSSI_THRESHOLD
The AM_VALID_RSSI_THRESHOLD property sets the RSSI threshold for a valid AM Seek/Tune. If the desired
channel RSSI is above this threshold, then it is considered valid. The CTS bit (and optional interrupt) is set when it
is safe to send the next command. This property may only be set or read in powerup mode.
Default: 10
Units: dBµV
AM_VALID_RSSI_THRESHOLD
15
14
13
12
10
9
8
7
6
5
4
3
0x00
AMVALRSSI[7:0]
0x00
0x0A
Bit
Name
15:8
Reserved
7:0
11
2
1
0
Function
Write 0 for (+) values, 0xFF for (–) values.
AMVALRSSI[7:0]
Sets the RSSI threshold for a valid AM Seek/Tune. Default is 10 dBµV.
Range is –128 to 127 in steps of 1 dB.
–128 = RSSI is not used as a criterion in determining the validity of a station.
Property 0x2200 AM_CHBW_SQ_MIN_MAX
The AM_CHBW_SQ_MIN_MAX property sets the maximum and minimum channel filter bandwidth in units of
100 Hz based on SNR or RSSI. To force a given channel filter bandwidth, set the min and max to the same value.
The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set
or read in powerup mode.
Default: 0x2314
Units: 100 Hz
AM_CHBW_MIN_MAX
15
168
14
13
12
11
10
9
8
7
6
5
4
3
MAX[7:0]
MIN[7:0]
0x23
0x14
2
1
Bit
Name
Function
15:8
MAX [7:0]
Sets the maximum channel filter bandwidth in units of 100 Hz. Default is
3.5 kHz. Range is 15–50.
7:0
MIN [7:0]
Sets the minimum channel filter bandwidth in units of 100 Hz. Default is
2 kHz. Range is 15–50.
Rev. 0.3
0
AN645
Property 0x2201 AM_CHBW_SQ_HIGH_THRESHOLD
The AM_CHBW_SQ_HIGH_THRESHOLD property sets the SNR or RSSI threshold for maximum channel filter
bandwidth. If the SNR or RSSI reported by the device is greater than the SQ High threshold programmed, then the
channel filter bandwidth will be set to the maximum value programmed through Property 0x2200. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 30
Units: dB (for SNR), dBµV (for RSSI)
AM_CHBW_SQ_HIGH_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SQMAX[6:0]
0x001E
Bit
Name
15:0
SQMAX[15:0]
Function
Sets the SNR or RSSI threshold for maximum channel filter
bandwidth.
Default is 30 dB. Range is 0–127 dB (or dBµV for RSSI).
Property 0x2202 AM_CHBW_SQ_LOW_THRESHOLD
The AM_CHBW_SQ_LOW_THRESHOLD property sets the SNR or RSSI threshold for minimum channel filter
bandwidth. If the SNR or RSSI reported by the device is less than the SQ Low threshold programmed, then the
channel filter bandwidth will be set to the minimum value programmed through Property 0x2200. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 15
Units: dB (for SNR), dBµV (for RSSI)
AM_CHBW_SQ_LOW_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SQMIN[6:0]
0x000F
Bit
Name
Function
15:0
SQMIN[15:0]
Sets the SNR or RSSI threshold for minimum channel filter bandwidth.
Default is 15 dB. Range is 0–127 dB (or dBµV for RSSI).
Rev. 0.3
169
AN645
Property 0x2203 AM_CHBW_SQ_WIDENING_TIME
The AM_CHBW_SQ_WIDENING_TIME property sets the channel filter bandwidth widening time based on SNR or
RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only
be set or read in powerup mode.
Default: 2048
Units: ms
AM_CHBW_SQ_WIDENING_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
WIDENING_TIME[15:0]
0x0800
Bit
Name
Function
15:0
WIDENING_TIME[15:0]
Sets the SNR or RSSI based channel filter bandwidth widening
time. Default is 2048 ms. Range is 1–32767 ms.
Property 0x2204 AM_CHBW_SQ_NARROWING_TIME
The AM_CHBW_SQ_NARROWING_TIME property sets the channel filter bandwidth narrowing time based on
SNR or RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property
may only be set or read in powerup mode.
Default: 16
Units: ms
AM_CHBW_SQ_NARROWING_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
NARROWING_TIME[15:0]
0x0010
170
Bit
Name
Function
15:0
NARROWING_TIME [15:0]
Sets the SNR or RSSI based channel filter bandwidth
narrowing time. Default is 16 ms. Range is 1–32767 ms.
Rev. 0.3
AN645
Property 0x2205 AM_CHBW_ASSI_MIN_MAX
The AM_CHBW_ASSI_MIN_MAX property sets the maximum and minimum channel filter bandwidth in units of
100 Hz. Based on adjacent signal strength indicator (ASSI.) To force a given channel filter bandwidth, set the min
and max to the same value. The CTS bit (and optional interrupt) is set when it is safe to send the next command.
This property may only be set or read in powerup mode.
Default: 0x3232
Units: 100 Hz
AM_CHBW_ASSI_MIN_MAX
15
14
13
12
11
10
9
8
7
6
5
4
3
MAX[7:0]
MIN[7:0]
0x32
0x32
2
1
0
Bit
Name
Function
15:8
MAX[7:0]
Sets the maximum channel filter bandwidth in units of 100 Hz. Default is
5 kHz. Range is 15–100.
7:0
MIN[7:0]
Sets the minimum channel filter bandwidth in units of 100 Hz. Default is
5 kHz. Range is 15–100.
Property 0x2206 AM_CHBW_ASSI_LOW_THRESHOLD
The AM_CHBW_ASSI_LOW_THRESHOLD property sets the ASSI threshold in dB for maximum channel filter
bandwidth. If the ASSI reported by the device is less than the ASSI Low threshold programmed, then the channel
filter bandwidth will be set to the maximum value programmed through Property 0x2205. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 10
Units: dB
AM_CHBW_ASSI_LOW_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ASSIMIN[15:0]
0x000A
Bit
Name
15:0
ASSIMIN[15:0]
Function
Sets the ASSI threshold for maximum channel filter bandwidth.
Default is 10 dB. Range is –128 to 127 dB.
Rev. 0.3
171
AN645
Property 0x2207 AM_CHBW_ASSI_HIGH_THRESHOLD
The AM_CHBW_ASSI_HIGH_THRESHOLD property sets the ASSI threshold in dB for minimum channel filter
bandwidth. If the ASSI reported by the device is greater than the ASSI High threshold programmed, then the
channel filter bandwidth will be set to the minimum value programmed through Property 0x2205. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 30
Units: dB
AM_CHBW_ASSI_HIGH_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ASSIMAX[15:0]
0x001E
Bit
Name
Function
15:0
ASSIMAX[15:0]
Sets the ASSI threshold for minimum channel filter bandwidth.
Default is 30 dB. Range is –128 to 127 dB.
Property 0x2208 AM_CHBW_ASSI_WIDENING_TIME
The AM_CHBW_ASSI_WIDENING_TIME property sets the channel filter bandwidth widening time based on ASSI.
The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set
or read in powerup mode.
Default: 16
Units: ms
AM_CHBW_ASSI_WIDENING_TIME
15
14
13
12
11
10
9
8
7
6
5
WIDENING[15:0]
0x0010
172
Bit
Name
15:0
WIDENING[15:0]
Function
Sets the channel filter widening time in ms.
Default is 16 ms. Range is 1–32767 ms.
Rev. 0.3
4
3
2
1
0
AN645
Property 0x2209 AM_CHBW_ASSI_NARROWING_TIME
The AM_CHBW_ASSI_NARROWING_TIME property sets the channel filter bandwidth narrowing time based on
ASSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only
be set or read in powerup mode.
Default: 16
Units: ms
AM_CHBW_ASSI_NARROWING_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
NARROWING[15:0]
0x0010
Bit
Name
Function
15:0
NARROWING[15:0]
Sets the channel filter narrowing time in ms.
Default is 16 ms. Range is 1–32767 ms.
Property 0x3100 AM_HICUT_SQ_HIGH_THRESHOLD
The AM_HICUT_SQ_HIGH_THRESHOLD property sets the SNR or RSSI level at which Hi-cut begins to band
limit. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only
be set or read in powerup mode.
Default: 8
Units: dB (for SNR), dBµV (for RSSI)
AM_HICUT_SQ_HIGH_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
0x000
SQ_HIGH[6:0]
0x000
0x08
Bit
Name
15:7
Reserved
6:0
SQ_HIGH[6:0]
1
0
Function
Always write 0.
Sets the SNR or RSSI level at which Hi-cut begins to band limit. Default is 8.
Range is from 0–127 dB (for SNR), dBµV (for RSSI).
Rev. 0.3
173
AN645
Property 0x3101 AM_HICUT_SQ_LOW_THRESHOLD
The AM_HICUT_SQ_LOW_THRESHOLD property sets the SNR or RSSI level at which Hi-cut reaches maximum
band limiting. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property
may only be set or read in powerup mode.
Default: 0
Units: dB
AM_HICUT_SQ_LOW_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
0x000
SQ_LOW[6:0]
0x000
0x08
Bit
Name
15:7
Reserved
6:0
SQ_LOW[7:0]
1
0
Function
Always write 0.
Sets the SNR or RSSI level at which Hi-cut reaches maximum band limiting.
Default is 0. Range is from 0–127 dB (for SNR), dBµV (for RSSI).
Property 0x3102 AM_HICUT_ATTACK_TIME
The AM_HICUT_ATTACK_TIME property sets the transition time in ms for which high cut lowers the cutoff
frequency. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may
only be set or read in powerup mode.
Default: 16
Units: ms
AM_HICUT_ATTACK_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK[15:0]
0x0010
174
Bit
Name
15:0
ATTACK[15:0]
Function
Sets the transition time in ms for which high cut lowers the cutoff frequency.
Default is 16 ms. Range is 16–32767 ms.
Rev. 0.3
AN645
Property 0x3103 AM_HICUT_RELEASE_TIME
The AM_HICUT_RELEASE_TIME property sets the transition time in ms for which high cut increases the cutoff
frequency. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may
only be set or read in powerup mode.
Default: 2000
Units: ms
AM_HICUT_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x07D0
Bit
Name
Function
15:0
RELEASE[15:0]
Sets the transition time in ms for which high cut increases the cutoff
frequency. Default is 2000 ms. Range is 16–32767 ms.
Property 0x3104 AM_HICUT_CUTOFF_FREQ
The AM_HICUT_CUTOFF_FREQ property sets the maximum and minimum Hi-cut transition frequencies in units
of 100 Hz. To force a given Hi-cut filter bandwidth, set the min and max to the same value. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 0x280A
Units: 100 Hz
AM_HICUT_CUTOFF_FREQ
15
14
13
12
11
10
9
8
7
6
5
4
3
MAX[7:0]
MIN[7:0]
0x28
0x0A
Bit
Name
15:8
MAX [7:0]
Maximum Hi-cut transition frequency in units of 100 Hz.
Default is 4 kHz. Range is 10–50.
7:0
MIN [7:0]
Minimum Hi-cut transition frequency in units of 100 Hz.
Default is 1 kHz. Range is 10–50.
2
1
0
Function
Rev. 0.3
175
AN645
Property 0x3105 AM_LOWCUT_MIN_FREQ
The AM_LOWCUT_MIN_FREQ property sets the minimum cutoff frequency. The LowCut tracks the HICUT
engine; therefore, thresholds are programmed in property 0x3100 and 0x3101. Setting the property to 0 disables
LowCut. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may
only be set or read in powerup mode.
Default: 0A
Units: Hz
AM_HICUT_CUTOFF_FREQ
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FREQ_MIN[15:0]
0x0000
Bit
Name
Function
15:0
FREQ_MIN[15:0]
Sets the minimum LOW-CUT cutoff frequency in Hz. Default is disabled.
Range is 0–1000 Hz.
0 = Disabled.
Property 0x3106 AM_LOWCUT_MAX_FREQ
The AM_LOWCUT_MAX_FREQ property sets the maximum cutoff frequency. The LowCut tracks the HICUT
engine, therefore thresholds are programmed in property 0x3100 and 0x3101. The CTS bit (and optional interrupt)
is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0A
Units: Hz
AM_HICUT_CUTOFF_FREQ
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FREQ_MAX[15:0]
0x0000
Bit
15:0
176
Name
Function
FREQ_MAX[15:0]
Sets the maximum LOW-CUT cutoff frequency in Hz. Note that if property
0x3105 (AM_LOWCUT_MIN_FREQ) is non-zero, this property must be set to
a value no less than property 0x3105.
Default is 0 Hz.
Range is 0–1000 Hz.
Rev. 0.3
AN645
Property 0x3300 AM_IBOC_CONTROL
(Si47777 Only)
The AM_IBOC_CONTROL property is the control property for IBOC Blend. DIGITAL_IO_INPUT_SAMPLE_RATE
and DIGITAL_IO_INPUT_FORMAT must be configured before IBOC Blend will function. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.
Default: 0x0000
AM_IBOC_CONTROL
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0x00
FORCE
0x00
ENABLE
0x00
0
0x00
0
Bit
Name
Function
15:9
Reserved
Always write 0.
Forces IBOC Blend. Default is 0.
0 = Do not force IBOC blend. The audio source is determined by the
IBOC control pin.
1 = Force IBOC blend. The audio comes from IBOC system.
8
Force
7:1
Reserved
0
Enable
Always write 0.
IBOC Blend Enable. Default is 0.
0 = The IBOC blend system is disabled.
1 = The IBOC blend system is enabled.
Property 0x3301 AM_IBOC_ANALOG_TO_HD_CROSSFADE_TIME
(Si4777 Only)
The AM_IBOC_ANALOG_TO_HD_CROSSFADE_TIME property sets the crossfade time between full analog and
full HD Digital audio in milliseconds. The CTS bit (and optional interrupt) is set when it is safe to send the next
command. This property may only be set or read in powerup mode.
Default: 1000
Units: ms
AM_IBOC_ANALOG_TO_HD_CROSSFADE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TIME[15:0]
0x03E8
Bit
Name
15:0
TIME[15:0]
Function
Sets the full analog to full digital crossfade time in ms.
Default is 1000 ms. Range is 0–22000 ms.
Rev. 0.3
177
AN645
Property 0x3302 AM_IBOC_HD_TO_ANALOG_CROSSFADE_TIME
(Si4777Only)
The AM_IBOC_HD_TO_ANALOG_CROSSFADE_TIME property sets the crossfade time from full HD Digital to full
analog audio in milliseconds. The CTS bit (and optional interrupt) is set when it is safe to send the next command.
This property may only be set or read in powerup mode.
Default: 1000
Units: ms
AM_IBOC_HD_TO_ANALOG_CROSSFADE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TIME[15:0]
0x03E8
Bit
Name
Function
15:0
TIME[15:0]
Sets the full digital to full analog crossfade time in ms.
Default is 1000 ms. Range is 0–22000 ms.
Property 0x3303 AM_IBOC_DYNAMIC_GAIN
(Si47777 Only)
The AM_IBOC_DYNAMIC_GAIN property sets the digital audio dynamic linear scaling factor. The CTS bit (and
optional interrupt) is set when it is safe to send the next command. This property may only be set or read in
powerup mode.
Default: 0x007F
AM_IBOC_DYNAMIC_GAIN
15
178
14
13
12
11
10
9
8
7
6
5
4
3
0x00
DGAIN[7:0]
0x00
0x7F
Bit
Name
15:8
Reserved
7:0
DGAIN[7:0]
2
1
0
Function
Always write 0.
Station dependent linear scaling factor in Q7 format. Range is 0–0x7F.
Rev. 0.3
AN645
Property 0x3304 AM_IBOC_STATIC_GAIN
(Si4777 Only)
The AM_IBOC_STATIC_GAIN property sets the digital audio static linear gain factor. Reverse the sign of this
number to obtain a 180 degree phase shift. The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This property may only be set or read in powerup mode.
Default: 0x0100
AM_IBOC_STATIC_GAIN
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SGAIN[15:0]
0x0100
Bit
Name
Function
15:0
SGAIN[15:0]
Static linear gain factor in Q7.8 format. Range is 0x8000–0x7FFF.
RESP
Bit
Name
Function
1
7:3
Reserved
1
2
HICUT_INT
If set indicates that the Hi-cut cutoff frequency is below the Hicut threshold set by WB_ACF_HICUT_THRESHOLD.
1
1
CHBW_INT
If set indicates that the Channel Filter Bandwidth is less than
the threshold set by WB_ACF_CHBW_THRESHOLD.
1
0
SOFTMUTE_INT
2
7:1
Reserved
2
0
SMUTE
3
7:0
SMATTN[7:0]
Soft mute attenuation level in dB.
Range: 0–31.
4
7:0
CHANBW[7:0]
Channel filter bandwidth in 100 Hz.
Range: 0–150.
5
7:0
HICUT [7:0]
Values may vary.
Is set Indicates that softmute attenuation has increased above
the softmute threshold as set by WB_ACF_SM_THRESHOLD.
Values may vary.
0 = Audio is not soft muted.
1 = Audio is soft muted.
Hi-cut cutoff frequency in units of 100 Hz.
Range: 10–50.
Rev. 0.3
179
AN645
10. Programming Examples
Table summarizes descriptions and programming examples in this section.
Table 18. Configuration and Operation Examples
Section Description
Operation
Configuration
180
10.1.1
Analog/Digital/MPX audio
10.1.2
IBOC HD Radio
10.1.3
AGC
10.1.4
Interrupts
10.1.5
Noise Blankers
10.1.6
Channel Equalizer
10.1.7
Pop Filter
10.1.8
Channel Filter Bandwidth
10.1.9
Softmute
10.1.10
Automatic Volume Control (AVC)
10.1.11
Blend
10.1.12
Hi-cut
10.1.13
Hi-blend
10.1.14
Primary/Companion
10.2.1
Tune
10.2.2
Seek
10.2.3
RDS
10.2.5
Check CTS and ERR
10.2.6
Check STC
Rev. 0.3
AN645
10.1. Configuration
The following tables summarize the available configuration options for AM and FM functions. Refer to section “9.
Commands and Properties”for detailed descriptions of commands and properties.
Table 19. FM Configuration Commands and Properties
Pin Configuration
Commands
Properties
Interrupts
0x1C
0x0000
GPIO Configuration
0x1A
Analog/MPX audio
0x1B
Digital audio
0x18
0x0200
ZIF
0x19
0x0600
RF/Audio Configuration
Commands
Properties
Softmute
0x0400
RF Signal routing, AGC thresholds and timing
0x0700
Channel spacing
0x1100
RSQ (RSSI, SNR) Interrupts
0x1200
ACF (Softmute, Channel Filter Bandwidth, Hi-blend, Hi-cut) Interrupts
0x1300
Tune/seek metric thresholds and timing (RSSI, SNR, frequency error)
0x2000
Channel filter bandwidth (RSSI, SNR, ASSI, ASSI200) range and timing
0x2200
Channel Equalizer
0x3400
Blend (RSSI/SNR, Multi-path, USN) range and timing
0x3500
Hi-cut (RSSI/SNR, Multi-path, USN) range and timing
0x3600
Hi-blend (RSSI/SNR, Multi-path, USN) range and timing
0x3700
IBOC Configuration
Commands
IBOC (cross-fade timing, dynamic and static gains)
RDS Configuration
0x3300
Commands
RDS Interrupts, FIFO size and management, decoder configuration
Rev. 0.3
Properties
Properties
0x4000
181
AN645
Table 20. AM Configuration Commands and Properties
Pin Configuration
Commands
Properties
Interrupts
0x1C
0x0000
GPIO Configuration
0x1A
Analog audio
0x1B
Digital audio
0x18
0x0200
ZIF
0x19
0x0600
RF/Audio Configuration
Commands
Properties
Power line filtering
0x0300
Softmute
0x0400
AVC (automatic volume control)
0x0500
RF Signal routing, AGC thresholds and timing
0x0700
Channel spacing
0x1100
RSQ (RSSI, SNR) Interrupts
0x1200
ACF (Softmute, Channel Filter Bandwidth, Hi-cut) Interrupts
0x1300
Tune/seek metric thresholds and timing (RSSI, SNR, frequency error)
0x2000
Channel filter bandwidth (RSSI, SNR, ASSI) range and timing
0x2200
Hi-cut (RSSI/SNR) range and timing
0x3100
IBOC Configuration
Commands Properties
IBOC (cross-fade timing, dynamic and static gains)
182
Rev. 0.3
0x3300
AN645
10.1.1. Analog/Digital/MPX audio
Analog, digital and MPX audio setup includes pin and sample rate (if applicable) configuration.
1. Complete steps up to and including 5 in section 5.1 Powerup one Receiver from Internal Memory or 10 in
section 5.2 Powerup one Receiver from a Patch.
2. Send the ANA_AUDIO_PIN_CFG command to route analog left and right channel to LOUT/ROUT pins, or
to route the MPX to the LOUT pin. This step may be omitted if analog audio is not required.
Example:
ANA_AUDIO_PIN_CFG Command
Action
Data
Description
CMD
0x1B
ANA_AUDIO_PIN_CFG
ARG1
0x02
2 = LOUT/ROUT pins configured to output audio.
3 = LOUT is configured for MPX
out and ROUT is disabled.
STATUS
→0x80
1. Send the DIG_AUDIO_PIN_CFG command to configure DCLK, DFS and DOUT for digital audio in slave
mode. Note that DCLK and DFS inputs should be stable before sending this command. This step may be
omitted if digital audio is not required.
Example:
DIG_AUDIO_PIN_CFG Command
Action
Data
Description
CMD
0x18
DIG_AUDIO_PIN_CFG
ARG1
0x0A
0x0A = configure DCLK pin for
digital audio slave mode.
ARG2
0x0A
0x0A = configure DFS pin for
digital audio slave mode.
ARG3
0x0C
0x0C = configure DOUT pin for
digital out.
ARG3
0x00
0x00 = Do not modify the
behavior of the BLEND pin.
STATUS
→0x80
1. Set property 0x0202 DIGITAL_IO_OUTPUT_SAMPLE_RATE to set the sample rate and 0x0203
DIGITAL_IO_OUTPUT_FORMATS to set the bit width and justification. This step may be omitted if digital
audio is not required.
2. Proceed to other examples in this section.
Rev. 0.3
183
AN645
10.1.2. IBOC HD Radio
IBOC HD radio setup requires configuration of input and output sample rates, I2S digital audio input and blend
control from the IBOC demodulator, I2S blended audio input to the system audio processor. Figure 16 shows a
conceptual diagram of the hardware interconnects.
HD Radio Demod
QOUT (Pin 26)
IOUT (Pin 25)
IQFS (Pin24)
IQCLK (Pin 23)
Digital I/Q ZIF
(I2S)
Demod
Audio /Data
Decoders
Master
4-wire mode
Master
Si4777
AM/FM Analog demodulation
Weak signal processing
IBOC
blend
HD
audio
ASRC
PLL
AM/FM
audio
Blended
audio
BLEND (Pin 30)
DCLK (Pin 29)
DFS (Pin 28)
DIN (Pin 27)
Blend Flag
Digital bit clock
Digital frame sync
HD audio
ASRC
DOUT2 (Pin 14)
DCLK2 (Pin 13)
DFS2 (Pin 18)
Blended audio
Digital bit clock
Digital frame sync
Audio
processing
X
3-wire mode
DSP
Master
Figure 16. System Implementation of HD-Radio Reception with IBOC Blend on the Si47777
1. Complete steps up to and including 5 in section “5.1. Powerup from Internal Memory”or 10 in section “5.2.
Powerup from a Patch”.
2. Set property 0x0301 AUDIO_MUTE.
184
Rev. 0.3
AN645
Example:
SET_PROPERTY Command
Action
Data
Description
CMD
0x13
SET_PROPERTY
ARG1
0x00
ARG2
0x03
ARG3
0x01
ARG4
0x00
ARG5
0x03
STATUS
→0x80
0x0301 = AUDIO MUTE
0x0003 = Mute left and right
3. Set property 0x0200 DIGITAL_IO_INPUT_SAMPLE_RATES and 0x0202
DIGITAL_IO_OUTPUT_SAMPLE_RATE to configure the input and output digital sample rates.
Example:
SET_PROPERTY Command
Action
Data
Description
CMD
0x13
SET_PROPERTY
ARG1
0x00
ARG2
0x02
ARG3
0x00
ARG4
0xAC
ARG5
0x44
STATUS
→0x80
0x0200 = DIGITAL_IO_INPUT_SAMPLE_RATES
0xAC44 = 44.1 kHz
SET_PROPERTY Command
Action
Data
Description
CMD
0x13
SET_PROPERTY
ARG1
0x00
ARG2
0x02
ARG3
0x02
ARG4
0xAC
ARG5
0x44
STATUS
→0x80
0x0202 = DIGITAL_IO_OUTPUT_SAMPLE_RATES
0xAC44 = 44.1 kHz
4. Send the DIG_AUDIO_PIN_CFG command to configure DCLK, DFS and DIN for I2S audio input in slave
mode and the BLEND pin to select the mode of the audio combiner. Note that DCLK and DFS inputs
Rev. 0.3
185
AN645
should be stable before sending this command.
Example:
DIG_AUDIO_PIN_CFG Command
Action
Data
Description
CMD
0x18
DIG_AUDIO_PIN_CFG
ARG1
0x0A
0x0A = configure DCLK pin 29
for digital audio in slave mode.
ARG2
0x0A
0x0A = configure DFS pin 28
for digital audio in slave mode.
ARG3
0x0D
0x0D = configure DIN pin 27 for
digital in.
ARG3
0x17
0x17 = configure BLEND pin 30
to select the mode of the
audio combiner (analog or HD).
STATUS
→0x80
5. Send the ZIF_PIN_CFG command to configure IOUT, QOUT, IQCLK and IQFS pins for ZIF output in I2S
master mode.
Example:
ZIF_PIN_CFG Command
Action
Data
Description
CMD
0x19
ZIF_PIN_CFG
ARG1
0x15
0x15 = configure IQCLK pin 23
for I/Q output in master mode.
ARG2
0x15
0x15 = configure IQFS pin 24
for I/Q output in master mode.
ARG3
0x16
0x16 = configure IOUT pin 25
for I/Q output in master mode.
ARG3
0x16
0x16 = configure QOUT pin 26
for I/Q output in master mode.
STATUS
→0x80
6. Send the IC_LINK_GPIO_CTL_PIN_CFG command to configure DCLK2 and DOUT2 pins in I2S slave
mode. Note that the DCLK2 input should be stable before sending this command.
186
Rev. 0.3
AN645
Example:
GPIO_CTL_PIN_CFG Command
Action
Data
Description
CMD
0x1A
GPIO_CTL_PIN_CFG
ARG1
0x00
ARG2
0x00
ARG3
0x0A
0x0A = Configure ICON pin as
DCLK2 in slave mode.
ARG4
0x0E
0x0E = Configure ICOP pin as
DOUT2 in slave mode.
STATUS
→0x80
7. Send the INTB_PIN_CFG command to configure DFS2 in I2S slave mode. Note that the DFS2 input
should be stable before sending this command. In this example, the interrupt pin is set to the A1 pin. Note
that only the A0 pin is available for I2C address selection in this mode. Note also that the interrupt pin can
be moved to the A1 pin with a POWER_UP option.
Example:
INTB_PIN_CFG Command
Action
Data
Description
CMD
0x1C
INTB_PIN_CFG
ARG1
0x0A
0x0A = Configure the DFS2 pin 18
for digital audio in slave mode.
ARG2
0x28
0x28 = Configure the A1 pin as the
interrupt.
ARG3
0x00
ARG4
0x00
STATUS
→0x80
8. Enable the IBOC blend system.
SET_PROPERTY Command
Action
Data
Description
CMD
0x13
SET_PROPERTY
ARG1
0x00
ARG2
0x33
ARG3
0x00
ARG4
0x00
ARG5
0x01
STATUS
→0x80
0x01 = enable
9. Note that tuning requires setting the HD bit for proper bandwidth configuration. See Section 9.2.1 Tune.
Proceed to other examples in this section.
Rev. 0.3
187
AN645
10.1.3. AGC
For FM mode, the AGC default configuration is generally optimal. The following section describes the settings and
options. AGC settings may be over-ridden by setting property 0x0710 FM_AGC_OVERRIDE and the state of the
AGC peak detectors may be monitored by sending command 0x17 AGC_STATUS.
10.1.3.1. FM
FM AGC configuration involves setting signal routing, AGC and peak detector.
The default property settings are configured for routing through the LNA input (instead of directly to the mixer) with
50 Ω LNA impedance as shown in Figure 17.
FMAGC2
FMAGC1
FMVAR
FMXIP
RF Pkd
FMXIN
RFREG
FMO
Reg
RL
LNA
50 
FMI
to AM
RF Pkd
Si477x
Figure 17. FM Single Receiver System Diagram
For optimal weak signal, blocker and intermodulation performance, the default property settings are configured to
disable the LNA peak detector and associated attack/release time constants, and enable the mixer peak detector
thresholds to 85 dBµV and 3 dB hysteresis, with an attack time of 4 ms and release time of 80 ms.
To improve weak signal performance at the expense of intermodulation performance, the mixer peak detector
thresholds may be increased to as high as 93 dBµV. To improve blocker and intermodulation performance at the
expense of weak signal performance, the mixer peak detector thresholds may be decreased to as low as 79 dBµV.
To improve impulsive noise desensitization (caused by engaging the AGC) at the expense of AGC response time,
the mixer peak detector attack time may be increased from 4 ms to an attack time greater than the period of the
impulses.
188
Rev. 0.3
AN645
10.1.3.2. AM
AM AGC configuration involves configuring signal routing, AGC and peak detector characteristics.
The default property settings are configured for optimal performance with the harmonic rejection enabled, IF AGC
attack time of 80 ms and release time of 804 ms, RF attack time of 8 ms and RF release time of 800 ms.
10.1.4. Interrupts
The interrupt status can be monitored by sending command 0x15 GET_INT_STATUS. Note that the command
response varies based on FM or AM mode. Interrupt pins can be configured by sending command 0x1C
INTB_PIN_CFG.
Property 0x0000 INT_CTL_ENABLE enables top-level interrupt sources and interrupt repetition characteristics.
Property group 0x1200 configures RSQ (RSSI, SNR) interrupts. Property group 0x1300 configures ACF (Softmute,
Channel Filter Bandwidth, Hi-blend, Hi-cut) interrupts. Note that Hi-blend only applies to FM mode operation.
Property group 0x4000 configures RDS interrupts.
10.1.5. Channel Equalizer
Property 0x3400 enables and disables the FM multipath channel equalizer.
Multi-path interference results in frequency-selective and frequency-flat fading of the FM signal at the receiver.
Frequency-selective fading causes different frequencies of an input signal to be attenuated and phase shifted
differently in a channel. Frequency-selective fading gives rise to notches in the frequency response of the channel.
The channel equalizer performs blind equalization utilizing proprietary constant modulus algorithm (CMA) to
restore the flat response of the channel.
The channel equalizer is enabled when multipath > 8% and disabled when multipath < 4% for stereo, when
multipath > 30% and disabled when multipath < 25% for mono, enabled when max(LASSI, HASSI) > 30 dB and
disabled when max(LASSI, HASSI) < 20 dB, enabled when ASSI200 > 50 dB and disabled when ASSI200 <
40 dB. Stereo is set if the PLL is locked or there is significant energy at the pilot. If any condition is satisfied, the
channel equalizer will be enabled.
Table 21 summarizes the metric conditions that will enable the equalizer.
Table 21. Equalizer Enable Conditions
Metric
Enable Threshold
Disable Threshold
Multipath (Stereo)
> 8%
< 4%
Multipath (Mono)
> 30%
< 25%
max (LASSI, HASSI)
> 30 dB
< 20 dB
ASSI200
> 50 dB
< 40 dB
Rev. 0.3
189
AN645
10.1.6. Channel Filter Bandwidth
10.1.6.1. FM
Property group 0x2200 configures channel filter bandwidth characteristics for FM mode.
Five independent channel filter bandwidth engines can be configured using RSSI (weak signal engine), ASSI100
(absolute value of difference between ±100 kHz channel RSSI), ASSI200 (sum of ±200 kHz channel RSSI minus
desired channel RSSI), and 200 kHz blocker deviation as the metric. For RSSI, ASSI100, and ASSI200, channel
filter bandwidth ranging from minimum to maximum occurs at the specified widening rate as the metric increases
above the minimum threshold and reaches maximum threshold. Channel filter bandwidth ranging from maximum to
minimum occurs at the specified narrowing rate as the metric decreases below the maximum threshold and
reaches the minimum threshold. For 200 kHz blocker deviation, channel filter bandwidth ranging from 80 to 32 kHz
occurs at 1 ms rate as the metric increases above 75 kHz and reaches 100 kHz. Channel filter bandwidth ranging
from 32 to 80 kHz occurs at the 300 ms rate as the metric decreases below 100 kHz and reaches 75 kHz. The
resulting channel filter bandwidth is the minimum of the result of the five blend engine calculations.
Property 0x220F FM_CHBW_WEAKSIG_THR is used to set the hysteresis window for enabling the weak signal
RSSI engine. The default is to enable above 16 dBuV RSSI and disable below 14 dBµV RSSI. Note that this
hysteresis range is always determined by RSSI and is not configurable with the FM_ACF_CONTROL_SOURCE
property.
Property 0x2210 FM_CHBW_BLOCKER_THR is used to set the hysteresis window for engaging the 200 kHz
blocker engine. The default is to enable above 20 dB ASSI200 and disable below 10 dB ASSI200. Note that 2 dB
ASSI200 indicates that the sum of the energy at +200 kHz and –200 kHz is 20 dB greater than the desired
channel. The 200 kHz blocker deviation engine is only enabled when sufficient pilot energy is present on the
desired channel.
10.1.6.2. AM
Property group 0x2200 configures channel filter bandwidth characteristics for AM mode.
Two independent channel filter bandwidth engines can be configured using RSSI or SNR and ASSI (independent
±9/10 kHz channel RSSI relative to on-channel RSSI). Channel filter bandwidth ranging from minimum to
maximum occurs at the specified widening rate as the metric increases above the minimum threshold and reaches
maximum threshold. Channel filter bandwidth ranging from maximum to minimum occurs at the specified
narrowing rate as the metric decreases below the maximum threshold and reaches the minimum threshold. The
resulting channel filter bandwidth is the minimum of the result of the two blend engine calculations.
Property 0x1306 AM_ACF_CONTROL_SOURCE is used to select RSSI or SNR as a metric for the channel filter
bandwidth.
10.1.7. Softmute
Property group 0x0400 configures softmute characteristics for FM and AM modes.
Property 0x1306 FM_ACF_CONTROL_SOURCE (or AM_ACF_CONTROL_SOURCE is used to select SNR
(default) or RSSI as a metric for the softmute engine. For FM and AM modes, the property is also used to select
whether an AFC rail condition will engage softmute. The most common cause for an AFC rail condition is tuning to
an idle channel.
Softmute engages as SNR (or RSSI) drops below a trigger threshold and audio level reaches a maximum
attenuation at the end threshold. Softmute releases as SNR (or RSSI) rises above the end threshold and audio
level reaches full level at the trigger threshold. The attack and release rates are configurable along with maximum
attenuation and trigger and end thresholds.
190
Rev. 0.3
AN645
10.1.8. Automatic Volume Control (AVC)
Property group 0x0500 configures automatic volume control (AVC) for AM mode.
The AVC minimum and maximum gain can be configured. The AVC maintains a constant carrier level.
10.1.9. Mono/stereo Blend
Property group 0x3500 configures the mono/stereo blend characteristics for FM mode.
Three independent blend engines can be configured with rates using RSSI, multipath, and USN as the metric.
Blend from minimum stereo to maximum stereo separation occurs at the specified attack rate as the metric
increases above the minimum threshold and reaches maximum threshold. Blend from maximum stereo to
minimum stereo separation occurs at the specified release rate as the metric decreases below the maximum
threshold and reaches the minimum threshold. The resulting stereo separation is the minimum of the result of the
six blend engine calculations.
10.1.10. Hi-cut
Hi-cut applies a lowpass filter to the L+R MPX audio.
10.1.10.1. FM
Property group 0x3600 configures the Hi-cut characteristics for FM mode.
Three independent blend engines can be configured with rates using RSSI, multipath, and USN as the metric. Hicut from minimum to maximum occurs at the specified attack rate as the metric increases above the minimum
threshold and reaches maximum threshold. Hi-cut from maximum to minimum occurs at the specified release rate
as the metric decreases below the maximum threshold and reaches the minimum threshold. The resulting Hi-cut is
the minimum of the result of the six blend engine calculations.
10.1.10.2. AM
Property group 0x3100 configures the Hi-cut characteristics for AM mode.
The blend engine can be configured with RSSI or SNR as the metric. Hi-cut from minimum to maximum occurs at
the specified attack rate as the metric increases above the minimum threshold and reaches maximum threshold.
Hi-cut from maximum to minimum occurs at the specified release rate as the metric decreases below the maximum
threshold and reaches the minimum threshold.
10.1.11. Hi-blend
Hi-blend applies a lowpass filter to the L-R MPX audio. Property group 0x3700 configures the Hi-blend
characteristics for FM mode.
Three independent blend engines can be configured with rates using RSSI, multipath, and USN as the metric. Hiblend from minimum to maximum occurs at the specified attack rate as the metric increases above the minimum
threshold and reaches maximum threshold. Hi-blend from maximum to minimum occurs at the specified release
rate as the metric decreases below the maximum threshold and reaches the minimum threshold. The resulting Hiblend is the minimum of the result of the six blend engine calculations.
Rev. 0.3
191
AN645
10.2. Operation
Operations including sending a command, checking CTS and ERR state, checking STC state, tune, seek, phase
diversity receiver mode selection and RDS are possible.
10.2.1. Tune
The tune operation provides options for configuring normal FM or HD bandwidth, tuning mode (validated normal
tune, unvalidated fast tune) and audio filter state management (re-initialize based on new channel, or smoothly
transition from current to new channel). In the case of tuning mode, 0x2000 property group sets the tune/seek
metric thresholds and timing (RSSI, SNR, frequency error). Note that references to “AFC Rail” in this manual refers
to a condition in which the frequency offset of the desired channel is outside the frequency error as configured with
property group 0x2000.
Start
1. Configure Tune
parameters
2. FM_TUNE_FREQ,
or AM_TUNE_FREQ
3. Check CTS & ERR
4. Check STC
End
1. Complete the appropriate steps in section “10.1. Configuration”.
2. Send the FM_TUNE_FREQ command to tune to a specific frequency. If the receiver has been muted (for
example during IBOC HD configuration), set property 0x0301 to disable mute. Note that AM tuning is very
similar. Refer to the AM_TUNE_FREQ command.
192
Rev. 0.3
AN645
Example:
FM_TUNE_FREQ Command
Action
Data
Description
CMD
0x30
FM_TUNE_FREQ
ARG1
0x00
Normal bandwidth (vs. HD
bandwidth), unconditionally
stay on channel, initialize audio
state based on new channel.
ARG2
0x27
0x27A6 = tune to 101.50 MHz.
ARG3
0xA6
ARG4
0x00
ARG5
0x00
STATUS
→0x80
CTS = 1
3. Check the CTS and ERR state to determine whether it is safe to send the next command. Refer to section
“10.2.4. Check CTS and ERR Status”.
4. Check the STC state to determine tune status. Refer to section xxx Check STC state.
5. Repeat steps 2, 3, and 4 as necessary.
Rev. 0.3
193
AN645
10.2.2. Seek
Start
1/2/3. Configure Seek
parameters
4. FM_SEEK_START
or AM_SEEK_START
5. Check CTS & ERR
6. Check STC
End
1. Complete the appropriate steps in section “10.1. Configuration”.
2. Set the 0x1100 property group to configure the seek start, stop and channel spacing.
3. Set the 0x2000 property group to set the tune/seek metric thresholds and timing (RSSI, SNR, frequency
error). Note that because every system will have unique signal gain and noise characteristics, RSSI and
SNR thresholds should be carefully evaluated.
4. Send the FM_SEEK_START command to begin the seek operation.
Example:
FM_SEEK_START Command
Action
Data
Description
CMD
0x30
FM_SEEK_START
ARG1
0x08
Seek up, don’t wrap at the top
of the band.
STATUS
→0x80
CTS = 1
5. Check the CTS and ERR state to determine whether it is safe to send the next command. Refer to section
“10.2.4. Check CTS and ERR Status”.
6. Check the STC state to determine seek status and abort if desired. Refer to Check STC state.
7. Repeat steps 4, 5, and 6 as necessary.
194
Rev. 0.3
AN645
10.2.3. RDS
1. Complete the appropriate steps in section “10.1. Configuration”and section “10.2.1. Tune”.
2. Set the 0x4000 property group to configure RDS Interrupts, FIFO size and management, and decoder
configuration.
3. (Optional) Send the FM_RDS_BLOCKCOUNT command to verify RDS block error rate. The block error
rate is defined as BLER = (UNCORRECTABLE + (EXPECTED-RECEIVED)) / EXPECTED.
Example:
FM_RDS_BLOCKCOUNT Command
Action
Data
Description
CMD
0x37
FM_RDS_BLOCKCOUNT
ARG1
0x01
Clear the block count.
STATUS
→0x80
CTS = 1
RESP1
→0x00
RESP2
→0x27
RESP3
→0x1F
RESP4
→0x24
RESP5
→0x8B
RESP6
→0x00
RESP7
→0x1B
Expected 0x271F = 10015
Received 0x248B = 9355
Uncorrectable 0x001B = 27
Rev. 0.3
195
AN645
In this example, the BLER = (27 + (10015-9355)) / 10015 = 6.8%.
4. Send the FM_RDS_STATUS in response to a configured RDS interrupt or at a set time interval. For
example, an interrupt can be configured when the 25 group FIFO has any number of entries between 1
and 25. Alternatively, the command can be sent every 88 ms (time for one group to be received) to 2.2
seconds (time for 25 groups to be received). The FM_RDS_STATUS command must be called once for
each entry. The FIFOUSED field can be used to monitor FIFO status. Refer to the RDS and RBDS
specifications for further decoding information.
Example:
FM_RDS_STATUS Command
Action
Data
Description
CMD
0x36
FM_RDS_STATUS
ARG1
0x01
Acknowledge the STC interrupt.
STATUS
→0x80
CTS = 1
RESP1
→0x00
RESP2
→0x1A
TP/PTY has changed, PI has
changed, synchronization has
changed.
RESP3
→0x05
PTY = 5
RESP4
→0x3E
PI = 0x3E67
RESP5
→0x67
RESP6
→0x01
FIFO used = 1 (out of a maximum of 25)
RESP7
→0x00
BLEA = 0, BLEB = 0, BLEC = 0,
BLED = 0
RESP8
→0x3E
BLOCKA = 0x3E67 (PI code)
RESP9
→0x67
RESP10
→0x20
RESP11
→0xA7
RESP12
→0x6C
RESP13
→0x74
RESP14
→0x65
RESP15
→0x72
BLOCKB = 0x20A7, group 2A
(RadioText), PTY = 5, A/B flag
= 0,
text segment address code = 7
BLOCKC = 0x6C74 (ASCII) =
“lt”
BLOCKD = 0x6572 (ASCII) =
“er”
5. Repeat steps 3 and 4 as necessary.
196
Rev. 0.3
AN645
10.2.4. Check CTS and ERR Status
After every command the CTS bit state should be checked to determine whether it is safe to send the next
command and the ERR bit state should be checked to determine whether an error has occurred.
Start
1. Start Timer
2. Read STATUS and
RESP1
3. CTS = 1?
No
4 .Timer >
125 ms?
No
4. Wait tCTS
Yes
Yes
5. ERR = 0?
4. STOP
No
6. ERR = 0x18?
Yes
Yes
6. Set CANCEL =1
and call
FM_RSQ_STATUS
or
AM_RSQ_STATUS
End
6. Wait 5ms
No
7. ERR = 0x20,
0x30 or 0x31?
No
Yes
7. STOP
6. Set STCACK =1
and call
FM_RSQ_STATUS
or
AM_RSQ_STATUS
6. Wait tCTS
Rev. 0.3
197
AN645
1. Start a timer capable of measuring 100 µs to 125 ms.
2. Read the STATUS byte and RESP1.
3. If CTS is set, it is safe to send the next command. Go to step 5.
4. If CTS is not set, check if the timer measures greater than 125 ms (time to execute the POWER_UP
command plus 20% margin). If it does, it is likely that the receiver is not in the power up state. Refer to "5.
Powerup and Powerdown" on page 4. If it doesn’t, wait time tCTS (100 µs). Refer to "8. Timing" on page 22.
5. If ERR (error) is set, check the specific error code reported in RESP1.
6. If the error code is 0x18, the tune or seek command is in progress and should be aborted by setting
CANCEL = 1 and sending the FM_RSQ_STATUS command (or AM_RSQ_STATUS), waiting 5 ms for the
seek operation to abort and set the STC bit, acknowledge and clear the STC bit by setting STCACK = 1
and sending the FM_RSQ_STATUS command (or AM_RSQ_STATUS) again, and then waiting time tCTS
(100 µs). Refer to "8. Timing" on page 22.
7. If the error code is 0x30 or 0x31 the boot operation failed and the powerup operation should be attempted.
Refer to "5. Powerup and Powerdown" on page 4. If the error code is 0x20 contact Silicon Labs. All other
errors are recoverable. and the error code reported in RESP1 will clear when the next valid command is
sent. See Table 22.
Table 22. Error Codes and Remedies
RESP1
Error Code
Explanation and Remedy
0x10
Bad command
Unsupported command, possibly due to programming error or incorrect device population. For example, an Si4771 is mistakenly placed
on a design instead of the Si4777 and and an attempt is made to configure the part for ZIF output.
0x11
Bad ARG1
0x12
Bad ARG2
0x13
Bad ARG3
0x14
Bad ARG4
0x18
Command Busy
0x20
198
Argument out of range or invalid mode, possibly due to programming
error or incorrect device population.
Wait for command completion, or abort tune/seek.
Bad internal memory Internal memory corruption. Contact Silicon Labs.
Patch CRC is incorrect. Recover by repeating the powerup
sequence with correct patch.
0x30
Bad patch
0x31
Bad boot mode
Mode is not supported. Recover by repeating the powerup sequence
with supported mode (AM, FM).
0x40
Bad property
Unsupported property, possibly due to programming error or incorrect
device population.
Rev. 0.3
AN645
10.2.5. Check STC Status
After every command the STC (seek/tune complete) bit state should be checked to determine the state of the tune
or seek command and abort the operation if desired.
Start
1. Read STATUS
2. STC = 1?
No
3. User Abort?
Yes
Yes
2. Set STCACK =1,
set ATTUNE = 1
and call
FM_RSQ_STATUS
or
AM_RSQ_STATUS
3. Set CANCEL =1
and call
FM_RSQ_STATUS
or
AM_RSQ_STATUS
2. Wait tCTS
3. Wait 5ms
No
4. Wait tSTC
End
1. Read the STATUS byte.
2. If STC (seek/tune complete) is set, set STCACK = 1 to acknowledge and clear the STC bit and set
ATTUNE = 1 to return RSQ metrics from tune time and call FM_RSQ_STATUS (or AM_RSQ_STATUS).
Rev. 0.3
199
AN645
Example:
FM_RSQ_STATUS Command
Action
Data
Description
CMD
0x32
FM_RSQ_STATUS
ARG1
0x05
Return metrics from tune time,
acknowledge the STC interrupt.
STATUS
→0x81
CTS = 1, STC = 1
RESP1
→0x00
RESP2
→0x31
SNR ready, RSSI ready, valid
channel.
RESP3
→0x27
Tuning frequency 0x027A6 =
101.50 MHz
RESP4
→0xA6
RESP5
→0x10
Frequency offset = 16 ppm
RESP6
→0x25
RSSI = 37 dBµV
RESP7
→0x14
SNR = 20 dB
RESP8
→0x00
RESP9
→0xFB
–100 kHz channel signal
strength (LASSI) 0xFB = –5 dB
RESP10
→0xF4
+100 kHz channel signal
strength (HASSI) 0xFB =
–12 dB
RESP11
→0x0B
Multipath 0x0B = 11
RESP12
→0x0F
Reserved, values will vary.
RESP13
→0x00
0x000 = Antenna capacitance,
only for tracking filter applications
RESP14
→0x00
RESP15
→0xE5
±200 kHz channel signal
strength (ASSI) 0xE5 = –27 dB
RESP16
→0x2A
Ultrasonic noise (USN) 0x2A =
42
3. If STC is not set and the user wishes to abort the tune, set CANCEL = 1 to abort and call
FM_RSQ_STATUS (or AM_RSQ_STATUS). Wait 5 ms for the tune or seek to abort and set the STC bit.
4. Wait tSTC (21–40 ms depending AM or FM modes). Refer to "8. Timing" on page 22.
200
Rev. 0.3
AN645
DOCUMENT CHANGE LIST
Revision 0.1 to Revision 0.2


Removed support for STRONGDEV, and 4 MHz
crystal operation.
Added support for LowCut and ASSI-based VALID
tune/seek check.
Revision 0.2 to Revision 0.3








Updated " Property 0x2205
FM_CHBW_ASSI_MIN_MAX" on page 104.
Updated " Property 0x220A
FM_CHBW_ASSI200_MIN_MAX " on page 106.
Updated " Command 0x32 FM_RSQ_STATUS" on
page 64.
Updated " Property 0x0403
FM_SOFT_MUTE_RELEASE_TIME" on page 78.
Updated " Property 0x0404
FM_SOFT_MUTE_ATTACK_TIME" on page 78.
Updated " Property 0x4003
FM_RDS_CONFIDENCE" on page 136.
Updated " Property 0x0403
AM_SOFT_MUTE_RELEASE_TIME" on page 153.
Updated " Property 0x0404
AM_SOFT_MUTE_ATTACK_TIME" on page 154.
Rev. 0.3
201
Smart.
Connected.
Energy-Friendly
Products
Quality
Support and Community
www.silabs.com/products
www.silabs.com/quality
community.silabs.com
Disclaimer
Silicon Laboratories intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers
using or intending to use the Silicon Laboratories products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each specific
device, and "Typical" parameters provided can and do vary in different applications. Application examples described herein are for illustrative purposes only. Silicon Laboratories
reserves the right to make changes without further notice and limitation to product information, specifications, and descriptions herein, and does not give warranties as to the accuracy
or completeness of the included information. Silicon Laboratories shall have no liability for the consequences of use of the information supplied herein. This document does not imply
or express copyright licenses granted hereunder to design or fabricate any integrated circuits. The products must not be used within any Life Support System without the specific
written consent of Silicon Laboratories. A "Life Support System" is any product or system intended to support or sustain life and/or health, which, if it fails, can be reasonably expected
to result in significant personal injury or death. Silicon Laboratories products are generally not intended for military applications. Silicon Laboratories products shall under no
circumstances be used in weapons of mass destruction including (but not limited to) nuclear, biological or chemical weapons, or missiles capable of delivering such weapons.
Trademark Information
Silicon Laboratories Inc., Silicon Laboratories, Silicon Labs, SiLabs and the Silicon Labs logo, CMEMS®, EFM, EFM32, EFR, Energy Micro, Energy Micro logo and combinations
thereof, "the world’s most energy friendly microcontrollers", Ember®, EZLink®, EZMac®, EZRadio®, EZRadioPRO®, DSPLL®, ISOmodem ®, Precision32®, ProSLIC®, SiPHY®,
USBXpress® and others are trademarks or registered trademarks of Silicon Laboratories Inc. ARM, CORTEX, Cortex-M3 and THUMB are trademarks or registered trademarks of
ARM Holdings. Keil is a registered trademark of ARM Limited. All other products or brand names mentioned herein are trademarks of their respective holders.
Silicon Laboratories Inc.
400 West Cesar Chavez
Austin, TX 78701
USA
http://www.silabs.com
Similar pages