TI1 AFE8221IRFPQ1 Dual intermediate frequency (if) analog front-end for digital radio Datasheet

AFE8221-Q1
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DUAL INTERMEDIATE FREQUENCY (IF) ANALOG FRONT-END FOR DIGITAL RADIO
•
FEATURES
1
• Qualified for Automotive Applications
• Two Intermediate Frequency (IF)
Analog-to-Digital Converters (ADCs)
• Two 12-Bit Auxiliary Digital-to-Analog
Converters (DACs)
• 8-Bit Auxiliary ADCs with Four-Channel Input
Multiplexer (MUX)
• Integrated IF Digital Processing Core
• Integrated Circuitry for Third-Overtone Master
Clock Oscillator
• Wakeup Circuit/Real-Time Clock With Separate
Crystal Oscillator
234
•
•
•
Flexible Data Interface Optimized for TMS
Family of Digital Baseband Processors
Pin-Selectable SPI™ and I2C™ Control
Interfaces
3.3-V/1.8-V Supply (Integrated Regulator
Available to Optionally Generate 1.8-V Supply)
TQFP-144 (RFP) PowerPAD™ Package
APPLICATIONS
•
•
IF-Sampled AM/FM Radio
Hybrid Digital (HD) Digital Audio Broadcasting
(DAB) Digital Radio
DESCRIPTION
The AFE8221 implements the intermediate frequency (IF) sampling and processing functions of a digital radio
receiver system. It is designed to be used with TI's digital radio baseband processors and AM/FM tuners. The
AFE8221 can also be programmed by the baseband processor for use in conventional AM/FM and digital radio.
This unit includes two IF inputs with associated filtering and digital processing circuitry.
The receive circuit oversamples the radio tuner IF output to reduce noise and improve dynamic range. The IF
analog-to-digital converter (ADC) oversamples the IF input at rates up to 75 MHz. The AFE8221 then digitally
mixes, filters, and decimates the signal to provide I and Q output signals to the baseband processor. A clock
oscillator circuit is provided that can be used with an appropriate third-overtone crystal and external tank circuit to
generate the sampling clock for the IF ADCs.
The AFE8221 also includes a real-time clock and associated low-power oscillator circuit. Two auxiliary
digital-to-analog converters (DACs) are included for system control functions. An 8-bit auxiliary ADC and input
multiplexer (MUX) can be used for system diagnostic functions. Other features include 12 general-purpose
input/output (GPIO) lines, programmable interrupt generators, and an I2C master for communication between the
AFE and the tuner(s).
The AFE8221 is available in a TQFP-144 (20 mm × 20 mm) package and uses a 3.3-V and a 1.8-V power
supply. An onboard voltage regulator is included to optionally generate the 1.8-V digital supply for the AFE8221.
ORDERING INFORMATION (1)
PACKAGE (2)
TA
–40°C to 85°C
(1)
(2)
HTQFP – RFP
Tray of 60
ORDERABLE PART NUMBER
AFE8221IRFPQ1
TOP-SIDE MARKING
AFE8221Q
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
web site at www.ti.com.
Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.
1
2
3
4
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PowerPAD is a trademark of Texas Instruments.
SPI is a trademark of Motorola, Inc.
I2C is a trademark of NXP Semiconductors.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2008, Texas Instruments Incorporated
AFE8221-Q1
SBAS434 – DECEMBER 2008 ........................................................................................................................................................................................... www.ti.com
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
ABSOLUTE MAXIMUM RATINGS (1)
over operating free-air temperature range (unless otherwise noted)
Supply voltage range
Voltage between
AVDD
–0.5 V to 3.6 V
DVDD
–0.5 V to 3.6 V
IOVDD
–0.5 V to 3.6 V
AGND to DGND
–0.3 V to 0.5 V
AVDD to DVDD
–3.3 V to 3.3 V
VIN
Digital input voltages (2)
–0.3 V to (DVDD + 0.3 V)
VOUT
Digital data output voltage
–0.3 V to (DVDD + 0.3 V)
TA
Operating free-air temperature range
–40°C to 85°C
Tstg
Storage temperature range
–55°C to 125°C
(1)
(2)
Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
Measured with respect to DGND.
RECOMMENDED OPERATING CONDITIONS
over operating free-air temperature range (unless otherwise noted)
MIN
TYP
MAX
AVDD
Analog supply voltage
PARAMETER
3.14
3.3
3.6
V
DVDD
Digital supply voltage
1.6
1.8
2.0
V
IOVDD
Output driver supply voltage
1.6
3.6
V
Input common-mode voltage
VCM
Differential input voltage
VIH
High-level input voltage, digital inputs
VIL
Low-level input voltage, digital inputs
TA
Operating free-air temperature
2
V
2
VPP
0.7 × IOVDD
–40
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UNIT
V
0.25 × IOVDD
V
+85
°C
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): AFE8221-Q1
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POWER SUPPLY SPECIFICATIONS
TA = 25°C, AVDD = IOVDD = 3.3 V, DVDD = 1.8 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
130
155
mA
REG_ENB disabled
65
85
mA
REG_ENB disabled
35
50
mA
REG_ENB enabled
105
125
mA
REG_ENB disabled
660
mW
REG_ENB enabled
725
mW
Software power-down
Control register address 1 set to 0x0000
100
mW
Hardware power-down
PWD enabled
50
µW
Power Consumption
Analog supply current
Digital supply current
Digital I/O supply current
Power dissipation
Reduced-Power Modes
IF ADC SPECIFICATIONS
TA = 25°C, AVDD = IOVDD = 3.3 V, DVDD = 1.8 V, fS = 75 MHz (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
DC Accuracy
Input impedance
2
kΩ
Offset error
3.0
mV
Gain error
1.0
%FS
Peak differential, 1x gain
2.0
VPP
Peak differential, 2x gain
1.0
VPP
AVDD = 3.15 VDC to 3.6 VDC
72
dB
Full-scale input level
Power Supply
PSRR
Power-supply rejection ratio
References
REFP
Positive reference
1.9
2.0
2.1
V
REFN
Negative reference
0.9
1.0
1.1
V
VCM
Common-mode voltage
1.4
1.5
1.6
V
AC Performance
Input sample rate
SNR
SFDR
75
Signal-to-noise ratio within a limited Input 10.7 MHz, –1 dBFS, in 3-kHz passband
passband
Input 10.7 MHz, –1 dBFS, in 100-kHz passband
MHz
105
85
90
Third-order intermodulation
distortion
–7-dB signals at 10.656 MHz and 10.729 MHz
91
–10-dB signals at 10.656 MHz and 10.729 MHz
94
Spurious-free dynamic range
–1-dB input at 10.7 MHz, 100-kHz passband
88
96
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dBc
dB
dBc
3
AFE8221-Q1
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AUXILIARY DAC SPECIFICATIONS
TA = 25°C, AVDD = IOVDD = 3.3 V, DVDD = 1.8 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Resolution
Resolution
12
Bits
Input code 0x000
0
V
Input code 0x3FF
2.7
V
Output Voltage Range
Output voltage range
Settling Time
Settling time
0.1% of FSR
10
µs
DC Performance
Offset
±1
% of FSR
Gain error
±5
% of FSR
DNL
Monotonic
±0.5
LSB
INL
Offset and gain errors removed
±3.0
LSB
PSRR
Input code 0x200, AVDD = 3.15 VDC to 3.6 VDC
30
dB
AUXILIARY ADC SPECIFICATIONS
TA = 25°C, AVDD = IOVDD = 3.3 V, DVDD = 1.8 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Resolution
Resolution
10
Bits
Input code 0x00
0
V
Input code 0xFF
3.0
V
30
kΩ
Input Voltage Range
Input voltage range
Input Impedance
Input impedance
Conversion Time
Conversion Time
8704
MCLK
cycles
DC Performance
Offset
±1.0
% of FSR
Gain error
±1.5
% of FSR
DNL
Monotonic
–1.0
INL
Offset and gain errors removed
–1.5
PSRR
Midscale input, AVDD = 3.15 VDC to 3.6 VDC
4
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±0.5
30
1.5
LSB
1.5
LSB
dB
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DIGITAL I/O SPECIFICATIONS
TA = 25°C, IOVDD = 3.3 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
IIH
High-level input current
VIH = 1.6 V to 3.6 V
–10
10
µA
IIL
Low-level input current
VIL = 0 V to 0.4 V
–10
10
µA
VOH
High-level output voltage
IOH = –50 µA
VOL
Low-level output voltage
IOL = 50 µA
0.8 × IOVDD
V
0.2 × IOVDD
V
CLOCK OSCILLATOR SPECIFICATIONS
TA = 25°C, DVDD = 1.8 V, IOVDD = 3.3 V (unless otherwise noted)
PARAMETER
fXTAL
Crystal frequency
TEST CONDITIONS
See the Master Clock Oscillator section
MIN
20
TYP
MAX
UNIT
75
MHz
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IF_INP0
IF_INM0
PGA
S/H
IF_REFP
IF_VCM
IF_REFM
IF_BIAS
IF_INP1
IF_INM1
12-Bit
Pipeline
ADC
Attenuator
and
Overflow
Sensor
12-Bit
Pipeline
ADC
FIR Filter 1
2
RTC_REF
FIR Filter 2A
2
FIR Filter 2B
2
NCO
Attenuator
and
Overflow
Sensor
SCL0
SDA0
SCL1
SDA1
Dual
2
I C Master
6
CIC Filter
N
Quadrature
Mixer
NCO
Voltage
Reference
PGA
S/H
RTCI
RTCO
RTC_REF
Real-Time
Clock
CIC Filter
N
Quadrature
Mixer
Master
Oscillator
FIR Filter 1
2
Timing
Generator
FIR Filter 2A
2
FIR Filter 2B
2
IF Data Interface
Control
DAC
RT Clock
Oscillator
IF_DOUT3
IF_DOUT2
IF_DOUT1
IF_DOUT0
IF_DFSO
IF_DCLK
BB_WS
BB_BCK
BB_IDAT0
BB_QDAT0
BB_IDAT1
BB_QDAT1
PWD
REFCLK
RST
GRST
CDAC0
Interrupt
Generator
MCLKO
Control
DAC
GPIO
Control
Interface
MCLKI
CDAC1
WAKEUP
IRQ0
IRQ1
IRQ2
Aux ADC
GPIO0
GPIO1
GPIO2
GPIO3
GPIO4
GPIO5
GPIO6
GPIO7
GPIO8
GPIO9
GPIO10
GPIO11
AUX_ADC0
AUX_ADC1
AUX_ADC2
AUX_ADC3
MUX
CTRL_MODE
CS/A1
MISO/SDA
MOSI/A0
SCK/SCL
FUNCTIONAL BLOCK DIAGRAM
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TERMINAL ASSIGNMENTS
AVDD
AVDD
AVDD
AVDD
NC
NC
NC
SDA0
SCL0
VSS
AVDD
RTC_REF
RTC_REF
AVSS
DVSS
RTCI
RTCO
DVDD1
VSS
AVDD
AVSS
DVDD
IOVDD
DVSS
IOVSS
DVSS
DVSS
GPIO8
GPIO9
GPIO10
GPIO11
GPIO0
GPIO1
GPIO2
GPIO3
GPIO4
TQFP-144
Top View
144 143 142 141 140 139 138 137 136 135 134 133 132 131 130 129 128 127 126 125 124 123 122 121 120 119 118 117 116 115 114 113 112 111 110 109
NC
NC
NC
AUX_ADC0
AUX_ADC1
AUX_ADC2
AUX_ADC3
AVDD1
CDAC0
AVSS
CDAC1
AVDD1
AVDD1
AVSS
AVSS
AVSS
IF_INP0
IF_INM0
IF_VCM
IF_REFP
IF_REFM
AVSS
AVDD1
AVDD1
AVSS
AVSS
IF_BIAS
AVSS
IF_INM1
IF_INP1
AVSS
AVSS
AVSS
AVDD1
NC
NC
NC
GPIO5
106 GPIO6
105 GPIO7
104 DVDD
103 DVSS
102 REG_ENB
101 CTRL_MODE
100 SCK/SCL
99 MISO/SDA
98 MOSI/A0
97 CS/A1
96 IOVDD
95 IOVSS
94 IF_DOUT0
93 IF_DOUT1
92 IF_DOUT2
91 DVDD
90 DVSS
89 IF_DOUT3
88 IF_DCLK
87 IF_DFSO
86 IOVDD
85 IOVSS
84 DVDD
83 DVSS
82 NC
81 NC
80 NC
79 NC
78 NC
77 NC
76 NC
75 NC
74 NC
73 NC
1
108
2
107
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
AFE8221
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
AVDD
AVDD
AVDD
AVDD
NC
SDA1
SCL1
VSS
AVDD
REFCLK
REFCLK
AVSS
DVSS
MCLKI
MCLKO
DVDD2
VSS
AVDD
AVSS
DVDD
IOVDD
DVSS
IOVSS
BB_WS
BB_BCK
BB_IDAT0
BB_QDAT0
BB_IDAT1
BB_QDAT1
GRST
WAKEUP
IRQ0
IRQ1
IRQ2
PWD
RST
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72
NC – No connection
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TERMINAL FUNCTIONS
TERMINAL
NAME
NO.
FUNCTION
DESCRIPTION
NC
1
Open
No connect
NC
2
Open
No connect
NC
3
Open
No connect
AUX_ADC0
4
Analog input
Auxiliary ADC channel 0
AUX_ADC1
5
Analog input
Auxiliary ADC channel 1
AUX_ADC2
6
Analog input
Auxiliary ADC channel 2
AUX_ADC3
7
Analog input
Auxiliary ADC channel 3
AVDD1
8
Supply
3.3-V analog supply (internally switched)
CDAC0
9
Output
Control DAC 0 output
AVSS
10
Ground
Analog ground
CDAC1
11
Output
Control DAC 1 output
AVDD1
12
Supply
3.3-V analog supply (internally switched)
AVDD1
13
Supply
3.3-V analog supply (internally switched)
AVSS
14
Ground
Analog ground
AVSS
15
Ground
Analog ground
AVSS
16
Ground
Analog ground
IF_INP0
17
Input
IF ADC channel 0 positive input
IF_INM0
18
Input
IF ADC channel 0 negative input
IF_VCM
19
Output
IF ADC common-mode voltage
IF_REFP
20
Output
IF ADC positive reference
IF_REFM
21
Output
IF ADC negative reference
AVSS
22
Ground
Analog ground
AVDD1
23
Supply
3.3-V analog supply (internally switched)
AVDD1
24
Supply
3.3-V analog supply (internally switched)
AVSS
25
Ground
Analog ground
AVSS
26
Ground
Analog ground
IF_BIAS
27
Input
AVSS
28
Ground
IF_INM1
29
Input
IF ADC channel 1 negative input
IF_INP1
30
Input
IF ADC channel 1 positive input
AVSS
31
Ground
Analog ground
AVSS
32
Ground
Analog ground
AVSS
33
Ground
Analog ground
AVDD1
34
Supply
3.3-V analog supply (internally switched)
NC
35
Open
No connect
NC
36
Open
No connect
AVDD
37
Supply
3.3-V analog supply
AVDD
38
Supply
3.3-V analog supply
AVDD
39
Supply
3.3-V analog supply
AVDD
40
Supply
3.3-V analog supply
NC
41
Open
SDA1
42
Bidirectional
Channel 1 tuner I2C data
SCL1
43
Output
Channel 1 tuner I2C clock
AVSS
44
Ground
Analog ground
AVDD
45
Supply
3.3-V analog supply
REFCLK
46
Output
Inverted reference clock output
8
IF ADC bias input
Analog ground
No connect
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TERMINAL FUNCTIONS (continued)
TERMINAL
NAME
NO.
FUNCTION
DESCRIPTION
REFCLK
47
Output
Reference clock output
AVSS
48
Ground
Analog ground
DVSS
49
Ground
Digital ground (for MCLK oscillator)
MCLKI
50
Input
MCLKO
51
Output
MCLK oscillator output
DVDD2
52
Supply
1.8-V digital supply (for MCLK oscillator)
AVSS
53
Ground
Analog ground
AVDD
54
Supply
3.3-V analog supply
AVSS
55
Ground
Analog ground
DVDD
56
Supply
1.8-V digital supply
IOVDD
57
Supply
3.3-V digital I/O supply
DVSS
58
Ground
Digital ground
IOVSS
59
Ground
Digital I/O ground
BB_WS
60
Output
Secondary baseband word select
BB_BCK
61
Output
Secondary baseband word bit clock
BB_IDAT0
62
Output
Secondary baseband channel 0 output (I)
BB_QDAT0
63
Output
Secondary baseband channel 0 output (Q)
BB_IDAT1
64
Output
Secondary baseband channel 1 output (I)
BB_QDAT1
65
Output
Secondary baseband channel 1 output (Q)
GRST
66
Input
Global reset (active low)
WAKEUP
67
Output
WAKEUP interrupt output
IRQ0
68
Output
Interrupt output 0
IRQ1
69
Output
Interrupt output 1
IRQ2
70
Output
Interrupt output 2
PWD
71
Input
Power-down pin (active high)
RST
72
Input
Reset pin (active low)
NC
73
Open
No connect
NC
74
Open
No connect
NC
75
Open
No connect
NC
76
Open
No connect
NC
77
Open
No connect
NC
78
Open
No connect
NC
79
Open
No connect
NC
80
Open
No connect
NC
81
Open
No connect
NC
82
Open
No connect
DVSS
83
Ground
Digital ground
DVDD
84
Supply
1.8-V digital supply
IOVSS
85
Ground
Digital I/O ground
IOVDD
86
Supply
3.3-V digital I/O supply
IF_DFSO
87
Output
IF interface frame sync
IF_DCLK
88
Output
IF interface bit clock
IF_DOUT3
89
Output
IF interface data out 3
DVSS
90
Ground
Digital ground
DVDD
91
Supply
1.8-V digital supply
IF_DOUT2
92
Output
IF interface data out 2
MCLK oscillator input
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TERMINAL FUNCTIONS (continued)
TERMINAL
NAME
NO.
FUNCTION
DESCRIPTION
IF_DOUT1
93
Output
IF interface data out 1
IF_DOUT0
94
Output
IF interface data out 0
IOVSS
95
Ground
Digital I/O ground
IOVDD
96
Supply
3.3-V digital I/O supply
CS/A1
97
Input
SPI chip select (active low) / I2C address bit 1
MOSI/A0
98
Input
SPI data in / I2C address bit 0
MISO/SDA
99
Bidirectional
SCK/SCL
100
Input
SPI clock / I2C SCL
CTRL_MODE
101
Input
Control interface mode select (SPI = 0, I2C = 1)
REG_ENB
102
Input
Enable onboard DVDD regulator (active low)
DVSS
103
Ground
Digital ground
DVDD
104
Supply
1.8-V digital supply
GPIO7
105
Bidirectional
GPIO 7
GPIO6
106
Bidirectional
GPIO 6
GPIO5
107
Bidirectional
GPIO 5
NC
108
Open
GPIO4
109
Bidirectional
GPIO 4
GPIO3
110
Bidirectional
GPIO 3
GPIO2
111
Bidirectional
GPIO 2
GPIO1
112
Bidirectional
GPIO 1
GPIO0
113
Bidirectional
GPIO 0
GPIO11
114
Bidirectional
GPIO 11
GPIO10
115
Bidirectional
GPIO 10
GPIO9
116
Bidirectional
GPIO 9
GPIO8
117
Bidirectional
GPIO 8
DVSS
118
Ground/input
Digital ground/Test1
DVSS
119
Ground/input
Digital ground/Test0
IOVSS
120
Ground
Digital I/O ground
DVSS
121
Ground
Digital ground
IOVDD
122
Supply
3.3-V digital I/O supply
DVDD
123
Supply
1.8-V digital supply
AVSS
124
Ground
Analog ground
AVDD
125
Supply
3.3-V analog supply
AVSS
126
Ground
Analog ground
DVDD1
127
Supply
1.8-V digital supply (for RTC oscillator)
RTCO
128
Output
RTC oscillator output
RTCI
129
Input
DVSS
130
Ground
Digital ground (for RTC oscillator)
AVSS
131
Ground
Analog ground
RTC_REF
132
Output
RTC output
RTC_REF
133
Output
Inverted RTC output
AVDD
134
Supply
3.3-V analog supply
AVSS
135
Ground
Analog ground
SCL0
136
Output
Channel 0 tuner I2C clock
SDA0
137
Bidirectional
Channel 0 tuner I2C data
NC
138
Open
10
SPI data out / I2C SDA
No connect
RTC oscillator input
No connect
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TERMINAL FUNCTIONS (continued)
TERMINAL
FUNCTION
DESCRIPTION
NAME
NO.
NC
139
Open
No connect
NC
140
Open
No connect
AVDD
141
Supply
3.3-V analog supply
AVDD
142
Supply
3.3-V analog supply
AVDD
143
Supply
3.3-V analog supply
AVDD
144
Supply
3.3-V analog supply
AVSS
—
Analog ground
Center pad
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TIMING DIAGRAMS
Output Data Interface Timing
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
tD1
DCLK to DFSO delay
–2.9
3.7
ns
tD2
DCLK to DOUTx delay
–3.1
3.8
ns
DCLK
DFSO
IA[15]
DOUTx
tD1
IA[14]
IA[13]
IA[12]
tD2
Figure 1. Output Data Interface Timing
Primary Data Interface Timing
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
tD1
BCLK to WS delay
–2.9
3.7
ns
tD2
BCLK to DOUTx delay
–3.1
3.8
ns
BCLK
WS
IA[15]
DOUTx
tD1
IA[14]
IA[13]
IA[12]
tD2
Figure 2. Primary Data Interface Timing
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SPI Control Interface Timing
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
20
MHz
fSCK
Maximum SCK frequency
tL
CS lead time
Trailing CS to leading SCK
5.0
ns
tT
CS trail time
Trailing SCK to leading CS
5.0
ns
tI
CS idle time
Leading CS to trailing CS
5.0
ns
tSU3
MOSI to SCK setup time
5.0
ns
tH3
MOSI to SCK hold time
1.0
ns
tD4
SCK to MISO delay
1.0
10.4
ns
SCK
CS
MOSI
MISO
tSU3
tL
tH3
tT
tD4
tI
Figure 3. SPI Control Interface Timing
I2C Bus Interface Timing
PARAMETER
fSCK
SCK clock frequency
VIL
Input voltage, low
VIH
Input voltage, high
tSTART
MIN
TYP
MAX
UNIT
400
kHz
0
0.3 × VDD
V
0.7 × VDD
V
Setup time for START or repeated START condition
0.6
µs
tSTOP
Setup time for STOP condition
0.6
µs
tLOW
LOW period of SCK clock
1.3
µs
tHIGH
HIGH period of SCK clock
0.6
µs
100
tHD_DAT
Data hold time from SCK falling
tSU_DAT
Data setup time to SCK rising
tBUF
Bus free time between a STOP and START condition
(1)
(1)
ns
250
100 (1)
ns
250
µs
4.7
Valid when MCLK > 20 MHz; otherwise, is 250 ns.
SDA
VIH
VIL
SCK
tSTART
tLOW
tHIGH
tHD_DAT
tSU_DAT
tBUF
tSTOP
Figure 4. I2C Bus Interface Timing
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DETAILED DESCRIPTION
Reset Pins
The AFE8221 has two active-low reset pins, GRST and RST. When GRST is brought low, all registers on the
chip are brought to default values (0, unless otherwise specified). When RST is brought low, all registers are
brought to default values except for:
• Real-time clock registers (counters and alarms)
• Registers to configure the WAKEUP interrupt
• Registers controlling the GPIO pins
These registers are left in the previously programmed states.
Analog Supply Connections
A clean 3.3-V analog supply should be connected to all AVDD pins (37–40, 45, 54, 125, 134, and 141–144).
Limited decoupling is required on the AVDD pins; a 0.1-µF capacitor near pins 45 and 54 and another capacitor
near pins 125 and 134 should suffice.
The AFE8221 contains an internal analog switch that is used to disconnect power from the major analog blocks
when the PWD pin is high. When the PWD pin is low, the AVDD1 pins (8, 12, 13, 23, 24, and 34) are internally
connected to the AVDD pins (37–40 and 141–144). Since the AVDD1 pins are actually the active supply pins for
the IF ADC and other analog components, the AVDD1 pins should be heavily bypassed with a minimum of
parallel 0.1-µF and 0.01-µF ceramic capacitors at each pin (or pin pair).
Digital Supply Connections
The digital supply connections depend on whether the onboard regulators are used to generate the 1.8-V digital
core voltage (REG_ENB low); or if the digital core voltage comes from a system-level supply (REG_ENB high).
In either case, all IOVDD pins should be connected to the 3.3-V I/O supply and appropriately bypassed. If the
internal regulators are used, this supply also sources the current drawn by the digital core.
External 1.8-V Core Supply
If an external 1.8-V supply is used, all DVDD pins should be connected to the 1.8-V supply and appropriately
bypassed with 0.1-µF and 0.01-µF capacitors. DVDD1 and DVDD2 pins may also be connected directly to the
1.8-V supply or may be optionally connected through a small (1 Ω to 10 Ω) series resistor to reduce supply noise
coupling into the MCLK oscillator (powered through DVDD1) or the RTC oscillator (powered through DVDD2).
When using an external supply, the PWD pin disables the MCLK oscillator when high, shutting off the clock to
most of the digital core. As long as the external 1.8-V supply is maintained, all register settings in the digital core
are maintained when PWD is high.
Internal 1.8-V Regulator
If the internal 1.8-V regulator is used, then 0.1-µF and 0.01-µF decoupling capacitors should still be put at the
DVDD, DVDD1, and DVDD2 pins. DVDD2 should still be connected to the DVDD pins either directly or through a
small series resistor. DVDD1 must be isolated from DVDD and DVDD2.
While using the internal regulators, the MCLK oscillator and the internal regulators are disabled when the PWD
pin is high. This condition causes most of the register settings to be lost, except for the registers associated with
the real-time clock, GPIO, and WAKEUP interrupt. For this reason, the RST pin should be brought low prior to
bringing the PWD pin low (to come out of power-down). The RST pin should be held low for at least 10 ms after
PWD goes low to allow the internal regulators to stabilize.
Note that the internal regulators are linear regulators, and therefore are relatively inefficient. Power dissipation as
a result of the digital core almost doubles when the internal regulators are used (same core current, but drawn
from a 3.3-V supply instead of a 1.8-V supply). Whenever possible, the use of a more efficient external switching
regulator is encouraged in order to minimize overall system power as well as to reduce the thermal stress on the
AFE8221.
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Control Interface
Configuration and control data are written to the AFE8221 via the control interface. The control interface supports
two protocols, SPI and I2C. If the CTRL_MODE pin is tied low, then an SPI interface is implemented. If
CTRL_MODE is tied high, then an I2C protocol-compatible interface is implemented.
SPI Interface
The SPI interface consists of four signals: a serial clock (SCK), an active-low chip select (CS), a serial data input
(MOSI—master out, slave in), and a serial data output (MISO—master in, slave out). Data are transferred in
groups of 32 bits. The first 16 bits are the instruction, which indicates:
1. If data are to be written or to be read;
2. If the data target is a register or RAM; and
3. The address of the data target.
The second 16 bits are the data transfer, which is input on MOSI for a write cycle or output on MISO for a read
cycle.
Figure 5 shows an SPI write cycle. The cycle is initiated by the high-to-low transition of the CS line. 32 SCK
pulses clock the instruction and the data into the MOSI line. Data are clocked in MSB first. The first 16 bits are
the instruction. There are two possible write cycle instructions: register write and memory write. The formats for
these instructions are shown in Figure 6 and Figure 7, respectively.
The only information required for a register write is the seven-bit register address (REG_ADDR). For a memory
write, both the five-bit memory select (MEM) plus the six-bit memory address (MEM_ADDR) are required.
Following the 16-bit instruction, the 16-bit data word is clocked in, again MSB first. At the end of the write cycle,
this data word is written to the appropriate register or memory location in the AFE8221.
SCK
CS
MOSI
MISO
INSTRUCTION
DATA
NOTE: To terminate a Write/Read cycle, CS must be brought high.
Figure 5. SPI Control Interface Write Cycle
1
0
0
15
14
13
REG_ADDR
12
11
10
9
8
7
6
5
4
3
2
1
0
1
0
Figure 6. Register Write Instruction Format
1
0
1
15
14
13
MEM_ADDR
MEM
12
11
10
9
8
7
6
5
4
3
2
Figure 7. Memory Write Instruction Format
Figure 8 shows the SPI interface read cycle. It is similar to the write cycle, except that instead of the data word
being clocked into MOSI during the second half of the cycle, the data word is clocked out of MISO. Note that only
register reads are permitted; RAM reads cannot be read back.
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For reading and writing, data block transfers are supported. For a block transfer, multiple data words are
transmitted following the memory read or write instruction. The data words are read from or written sequentially
starting at the address contained in the instruction. The sequential access terminates when the CS line goes
high. Figure 9 shows a register block read cycle. In the illustration, three succeeding register locations are read
starting at address N. The block write cycle is similar except, of course, data are clocked into MOSI.
In all cases, the control interface is reset when CS goes high. If the final SCK is not received before CS goes
high, then the cycle ends prematurely. For a read cycle, data transfer terminates; for a write cycle, no data are
written to either a register or to memory.
I2C Slave Interface
The AFE8221 control interface can be configured to provide I2C slave operation. It has a 10-bit slave address of
00010010AB and complies with the Philips I2C specification. Note that address bits A and B are determined by
the state of the I2C address pins A1 and A0. The mapping of SPI pins to I2C pins is shown in Table 1.
Table 1. SPI/I2C Pin Mapping
CTRL_MODE = 1 (I2C)
CTRL_MODE = 0 (SPI)
2
Chip select (CS)
I C address bit (A1)
Master out slave in (MOSI)
I2C address bit (A0)
Master in slave out (MISO)
Serial data line (SDA)
SPI clock (SCK)
Serial clock line (SCL)
The AFE8221 I2C interface supports both fast mode (400K bits/sec) and standard mode (100K bits/sec)
operation. However, if the master crystal frequency is less than 20 MHz, then only standard mode is supported.
SCK
CS
MOSI
MISO
INSTRUCTION
DATA
Figure 8. SPI Control Interface Read Cycle
SCK
CS
MOSI
MISO
INSTRUCTION
DATA[N]
DATA[N+1]
DATA[N+2]
Figure 9. SPI Control Interface Block Read Cycle
As a reference, a typical data transfer on the I2C bus is described in Figure 10. Each data byte is eight bits long
and must be followed by an Acknowledge bit. Start and stop conditions are defined as a transition of the SDA
signal with SCL high. A pulse of the SCL clock signal indicates the transfer of data or an Acknowledge bit on the
SDA pin. The transmitting device drives SDA data during clock periods 1–8. The receiving device acknowledges
by driving SDA low during clock 9. Master devices always generate the SCL clock and initiate transactions. Refer
to the Philips I2C Bus Specification for further details.
The AFE8221 has 16-bit internal registers and operates on 16-bit instructions. Because the I2C interface is
inherently an 8-bit interface, special formats are required to send instructions and data between an I2C Master
and the AFE8221. The I2C Write Operation and I2C Read Operation sections describe these formats in detail.
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I2C Write Operation
Write operations require a start condition followed by two bytes describing both a 10-bit address format and the
AFE8221 10-bit slave address. The next two bytes must contain the 16-bit instruction word format described
previously in Figure 6 or Figure 7, depending on the internal resource being addressed. Finally, a pair of bytes
containing the 16-bit write data must be provided. If additional 16-bit writes are required, further pairs of bytes
may be used as part of a block transfer. After the final pair of write data bytes, an I2C stop condition must be
provided to terminate the transaction. Figure 12 illustrates a block write transfer of N 16-bit data words. Gray
areas denote slave-driven SDA cycles; white areas are master-driven.
I2C Read Operation
Read operations require a start condition followed by two bytes describing both a 10-bit address format and the
AFE8221 10-bit slave address. The next two bytes must contain the 16-bit instruction word format, as illustrated
in Figure 11. A repeated start followed by the first byte of the slave address is then required to create a
combined transaction. Note that the R/W bit is set to 1 (read), indicating that subsequent bytes are to be read
from the slave. The AFE8221 presents addressed 16-bit data words in 8-bit pairs until a NACK (N) is provided by
the master. After the final pair of read data bytes, an I2C stop condition must be provided to terminate the
transaction. Figure 13 illustrates a block read transfer of N 16-bit data words. Gray areas denote slave-driven
SDA cycles; white areas are master-driven.
SDA
SCL
MSB
1
LSB ACK
LSB R/W ACK MSB
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
S
P
START
CONDITION
STOP
CONDITION
Figure 10. Example Data Transfer on the I2C Bus
0
1
0
15
14
13
REG_ADDR
12
11
10
9
8
7
6
5
4
3
2
1
0
Figure 11. Register Read Instruction Format
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‘0’ Indicates Following Bytes
are Written to Slave
2
I C Reserved Combination
Indicating 10-Bit Addressing is
in Use
10-Bit Slave Address
Write
Start
S
1
1
1
1
0
0
0
Slave Address 1st 7 Bits
0
Slave
ACK
R/W
A
0
1
0
0
1
0
A
Slave Address 2nd Byte
Slave
ACK
Bits 15-8 of Instruction
A
A
Bits 7-0 of Instruction
A
A
A
Slave
ACK
Bits 7-0 of First 16-Bit Data Word
Slave
ACK
Bits 15-8 of Second 16-Bit Data Word
Slave
ACK
Slave
ACK
Slave
ACK
Bits 15-8 of First 16-Bit Data Word
B
A
Slave
ACK
Bits 7-0 of Second 16-Bit Data Word
A
¼
Slave
ACK
Bits 15-8 of Nth 16-Bit Data Word
A
Slave
ACK Stop
Bits 7-0 of Nth 16-Bit Data Word
A
P
Figure 12. Example I2C Write Operation
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‘0’ Indicates Following Bytes
are Written to Slave
2
I C Reserved Combination
Indicating 10-Bit Addressing is
in Use
10-Bit Slave Address
Write
Start
1
S
1
1
1
0
0
0
Slave Address 1st 7 Bits
0
Slave
ACK
R/W
A
0
1
0
0
1
0
A
Slave Address 2nd Byte
Slave
ACK
Bits 15-8 of Instruction
B
Slave
ACK
A
Slave
ACK
A
Bits 7-0 of Instruction
A
2
I C Reserved Combination
Bits 9 and 8 of the 10-Bit
Indicating 10-Bit Addressing is Slave Address
‘1’ Indicates Following Bytes
in Use
are Read from Slave
Read
Repeated
Slave
1
1
1
0
0
0
1 ACK
Start 1
Sr
Slave Address 1st 7 Bits
R/W
A
Master
ACK
Bits 15-8 of First 16-Bit Data Word
A
Master
ACK
Bits 7-0 of First 16-Bit Data Word
Master
ACK
Bits 15-8 of Second 16-Bit Data Word
A
A
Master
ACK
Bits 7-0 of Second 16-Bit Data Word
A
¼
Master
ACK
Bits 15-8 of Nth 16-Bit Data Word
A
Bits 7-0 of Nth 16-Bit Data Word
Master
NACK
Stop
N
P
Figure 13. Example I2C Read Operation
IF Analog-to-Digital Converters (IF_ADC0 and IF_ADC1)
IF_ADC0 and IF_ADC1 are 12-bit pipeline ADCs that are used to sample the output of the tuner(s). Figure 14
shows recommended connections for the IF ADCs.
The IF ADCs have three power modes controlled by ifadc_en[0] and ifadc_en[1]. Full-power mode occurs when
both ifadc_en[0] and ifadc_en[1] are high. In this case, both ADCs are biased to the highest levels and are ready
to operate. If only ifadc_en[0] or ifadc_en[1] is high, then the converters are operating in reduced-power mode,
where the enabled ADC is fully biased and ready to operate while the second ADC is in a low (but not zero) bias
state (a minimum bias current is necessary to maintain safe voltages within the ADC core). In low-power mode,
both ifadc_en[0] and ifadc_en[1] are low. In this case, all IF ADC circuits are in the minimum bias mode. Note
that to reach a true sleep mode, the analog supply to the IF ADC block must be turned off.
When ifadc_gain0 is low, IF_ADC0 is in its normal 1x gain operating state. If ifadc_gain0 is high, then the gain of
IF_ADC0 is changed to 2x. In a similar fashion, ifadc_gain1 controls the gain of IF_ADC1. Table 2 shows the
ifadc_en and ifadc_gain control variable parameters.
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Table 2. IF_ADC Control Register Settings
ADDRESS
BITS
ifadc_en[0]
PARAMETER
1
0
ifadc_en[1]
1
1
ifadc_gain0
1
2
ifadc_gain1
1
3
13W
17
IFP
IF_INP0
12pF
TUNER_0
13W
18
IFM
IF_INM0
VCM
AFE8221
13W
30
IFP
IF_INP1
12pF
TUNER_1
13W
IFM
29
19
VCM
IF_INM1
IF_VCM
IF_REFP
1mF
0.1mF
IF_REFM
20
IF_BIAS
21
27
0.1mF
56kW
0.01mF
0.01mF
0.1mF
0.1mF
1mF
0.1mF
Figure 14. IF ADC Connections
IF ADC Alarm/Attenuator
The output of each IF ADC is monitored to ensure that the full-scale input range is not exceeded. If an ADC
over-range condition occurs, an overflow signal is generated that may be used to generate an interrupt on the
IRQ line, depending on the settings in the IRQ interrupt generator.
In addition, programmable limits may be set for each IF ADC. If the absolute value of IF_ADC0 exceeds
if_adc_limit0 or the absolute value of IF_ADC1 exceeds ifadc_limit1, then an interrupt may be generated on IRQ
again depending on the settings in the IRQ interrupt generator.
In the case of an IF ADC event, the IRQ status register can be read back to determine the type of event and on
which ADC channel it occurred. The IRQ status register can be polled to determine if an IF ADC event has
occurred in the case where IF ADC events are masked from generating an interrupt.
The control variable ddc0_atten causes an attenuation of the IF_ADC0 output prior to the DDC. The attenuation
ranges in 3-dB steps from 0 dB (for ddc0_atten = 0) to –18 dB (for ddc0_atten = 6). ddc1_atten has the same
effect on the output of IF_ADC1.
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To better synchronize the IF ADC attenuator with the tuner automatic gain control (AGC), a delay may be
programmed between when a new value of ddc_atten is written and when it takes effect. When a new value of
ddc0_atten is written, a counter (driven by MCLK) is initialized to ddc0_delay. When the counter reaches zero,
the actual attenuation change occurs. Likewise, ddc1_delay affects ddc1_atten. Note that if a new ddc0_atten is
written before the delay counter has reached zero from the previous write, the previous write is discarded.
Table 3 shows the attenuator, delay, and limit control variables.
Table 3. IF ADC Control Register Settings
ADDRESS
BITS
ddc0_atten
PARAMETER
3
2:0
ddc1_atten
15
2:0
ddc0_delay
4
15:0
ddc1_delay
16
15:0
ifadc_limit0
46
11:0
ifadc_limit1
47
11:0
Digital Downconverter 0 (DDC0)
DDC0 operation is controlled by ddc_en[0]. When ddc_en[0] is 1, operation of DDC0 is enabled. If ddc_en[0] is
0, operation of DDC0 is disabled. Table 4 shows the DDC0 operation control settings.
Table 4. DDC Control Register Settings
PARAMETER
ADDRESS
BITS
ddc0_cic_dec_rate
9
8:0
ddc0_cic_scale
10
11:6
ddc0_cic_shift
10
5:0
ddc0_demod_freq[31:16]
5
15:0
ddc0_demod_freq[15:0]
6
15:0
ddc0_demod_phase[31:16]
7
15:0
ddc0_demod_phase[15:0]
8
15:0
ddc0_fir1_base_address
11
13:8
ddc0_fir1_mode
11
1:0
ddc0_fir1_ncoeffs
11
7:2
ddc0_fir1_nodec
14
9
ddc0_fir2_nodec
14
10
ddc0_fir2a_base_address
12
15:9
ddc0_fir2a_mode
12
1:0
ddc0_fir2a_ncoeffs
12
8:2
ddc0_fir2a_shift
14
3:0
ddc0_fir2b_base_address
13
15:9
ddc0_fir2b_mode
13
1:0
ddc0_fir2b_ncoeffs
13
8:2
ddc0_fir2b_shift
14
7:4
ddc0_interleave
14
8
ddc_en[0]
1
4
ddc_sync
1
6
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Quadrature Mixer/NCO
The NCO frequency and initial phase are set by the 32-bit unsigned variables ddc0_demod_freq and
ddc0_demod_phase. The I and Q outputs of the mixer can be calculated by Equation 1 and Equation 2.
I = ADC ´ cos(2pft + f)
(1)
Q = ADC ´ sin(2pft + f)
(2)
where ADC is the output of the IF analog-to-digital converter, f is the NCO phase offset (in radians) given by
Equation 3, and φ is the NCO phase offset (in radians) given by Equation 4.
ddc0_demod_freq
f = fMCLK
32
2
(3)
ddc0_demod_phase
f = 2p
32
2
(4)
The ddc_sync signal can be used to control the phase of the mixer. While the ddc_sync signal is high, the phase
accumulator is held to a constant value ddc0_demod_phase, essentially holding it to 0 in Equation 1 and
Equation 2. When the ddc_sync signal is brought low, the phase accumulator is incremented by the value
ddc0_demod_freq once per MCLK cycle.
CIC Filter
The first stage of decimation filtering is provided by a fifth-order CIC filter. The operation of the CIC filter is
controlled by the unsigned variables ddc0_cic_dec_rate, ddc0_cic_scale, and ddc0_cic_shift. The valid range for
ddc0_cic_dec_rate is from 4 to 256.
The inherent dc gain of the CIC filter is ddc0_cic_dec_rate. The control variables ddc0_cic_shift and
ddc0_cic_scale are used to reduce this very high gain before the signal is output to the next stage of the
decimation filter. The combined effect of ddc0_cic_dec_rate, ddc0_cic_shift, and ddc0_cic_scale produces an
overall dc gain for the CIC filter of Equation 5.
ddc0_cic_scale/32
5
GAIN = ddc0_cic_dec_rate
2ddc0_cic_shift
(5)
In general, ddc0_cic_shift and ddc0_cic_scale should be chosen to make GAIN as close to 1 as possible. For
example, if ddc0_cic_dec_rate is 20, setting ddc0_cic_shift to 22 and ddc0_cic_scale to 41 results in a GAIN of
0.9775.
First FIR Filter
The block following the CIC filter is a decimate-by-two finite impulse response (FIR) filter with programmable
coefficients. ddc0_fir1_mode sets the type of filter response—ODD (MODE = 00: symmetric impulse response,
odd number of taps), EVEN (MODE = 01: symmetric impulse response, even number of taps), HALFBAND
(MODE = 10), and ARBITRARY (MODE = 11: non-symmetric impulse response).
The 16-bit wide filter coefficients are stored in memory bank 0. Up to 64 coefficients can be stored in this
memory. Depending on the types of filters desired and the number of taps, coefficients for multiple filter
responses may be stored in the memory bank. The filter response may be changed simply by updating the
control register with new values for ddc0_fir1_mode, ddc0_fir1_ncoeff, and ddc0_fir1_base_addr.
ddc0_fir1_ncoeff defines the number of unique filter coefficients that make up the filter response.
ddc0_fir1_base_addr defines the memory location where the first filter coefficient is stored. The actual filter
length is a function of the ddc0_fir1_mode and ddc0_fir1_ncoeff, as shown in Equation 6.
22
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Filter Length = 2 ´ (ddc0_fir1_ncoeff - 1) + 1 for ODD
Filter Length = 2 ´ ddc0_fir1_ncoeff for EVEN
Filter Length = 4 ´ (ddc0_fir1_ncoeff - 1) + 1 for HALFBAND
Filter Length = ddc0_fir1_ncoeff for ARBITRARY
(6)
The maximum filter length that can be realized is limited by two factors. First, the number of clock cycles
between successive filter outputs limits the number of coefficients that can be processed, as shown in
Equation 7.
ddc0_fir1_ncoeff £ 2 ´ ddc0_cic_dec_rate
(7)
where ddc0_cic_dec_rate is the decimation ration of the CIC filter.
Second, the size of the data memory (which stores incoming data samples) limits filter length to 62 taps. Note
that two data memory locations are required to filter processing.
The dc gain of the FIR filter depends on the coefficient values and the filter mode. For ODD mode and
HALFBAND mode, the dc gain is given by Equation 8:
hNCOEFF +
NCOEFF - 1
GAIN =
å
n=1
2hn
15
2 -1
(8)
th
where hn is the n of NCOEFF filter coefficients stored in memory.
For EVEN mode the, dc gain is shown by Equation 9:
NCOEFF
å 2hn
GAIN =
n=1
15
2 -1
(9)
while for ARBITRARY mode the gain is shown by Equation 10:
NCOEFF
å hn
GAIN =
n=1
15
2 -1
(10)
Second FIR Filters
The first FIR filter is followed by two parallel second FIR filters, FIR2A and FIR2B. Duplicate filters allow the
output of two I and Q output streams with different bandwidths. For example, the bandwidth of FIR2A may be set
wide to accommodate reception of digital broadcasts, while FIR2B may be set narrower to receive an analog
broadcast sharing the same band. Coefficients for FIR2A are stored in memory bank 1 (MEM = 1) and
coefficients for FIR2B are stored in memory bank 2 (MEM = 2).
The operation of the second FIR filter is similar to the first FIR filter with several notable exceptions. First, the
depths of the coefficient and data memories are doubled to 128. This size increase allows for filters up to 126
taps to be realized without running out of data memory. It also allows longer sets of filter coefficients to be stored
in coefficient memory.
Second, because of the additional decimation by two from the first FIR filter, twice as many MCLK cycles are
available to process coefficients, increasing the maximum allowable value of NCOEFF, as shown in Equation 11
and Equation 12.
ddc0_fir2a_ncoeff £ 4 ´ ddc0_cic_dec_rate
(11)
ddc0_fir2b_ncoeff £ 4 ´ ddc0_cic_dec_rate
(12)
Third, in the first FIR filter the total of all the filter tap weights must add up to (215 – 1) to achieve unity gain
through the filter. With longer filters (and therefore, smaller coefficients), frequency response errors may be
introduced as a result of coefficient truncation. A Shift parameter has been added to the second FIR filter to
alleviate this problem. The total of all filter tap weights must add up to (215+ddc0_fir2a_shift – 1) to achieve unity gain
through FIR2A (similarly for ddc0_fir2b_shift and FIR2B). Note that shift values for FIR2A and FIR2B can be set
separately.
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Extended-Length Filter Mode
If FIR2A or FIR2B cannot provide enough filter taps to achieve the desired frequency response, setting control bit
ddc0_interleave puts the two filters into an interleaved mode that doubles the length of the filter that can be
realized. However, there are several limitations:
1. Only odd symmetrical filters may be realized;
2. The filter length M must be such that (M + 1)/4 is an integer; and
3. Only one filter can be realized (in ddc_interleave mode the A and B outputs are identical: IB = IA and QB =
QA).
In addition to setting the ddc0_interleave bit, FIR2A must be set to EVEN mode and FIR2A must be set to ODD
mode. ddc0_fir2a_ncoeff and ddc0_fir2b_ncoeff are both set to (M + 1)/4. ddc0_fir2a_shift and ddc0_fir2b_shift
should be identical. There are no restrictions on ddc0_fir2a_base_addr or ddc0_fir2b_base_addr.
The M-tap filter has (M + 1)/2 unique coefficients. The first, third, fifth, etc. coefficients are loaded into the FIR2A
coefficient memory; the second, fourth, sixth, etc. coefficients are loaded into the FIR2B memory. The center
coefficients of the filter end up as the last coefficient loaded into FIR2B.
FIR Filter Transfer Functions
Equation 13 to Equation 21 show transfer functions and dc gain for the various filter modes. Generic names for
the control variables are used; just substitute the appropriate variable (that is, ddc0_fir2a_ncoeff for NCOEFF) as
necessary. Also, note that SHIFT has a value of 0 for FIR1.
Basic Filter Modes
NCOEFF - 1
HEVEN(z) =
å
n=0
NCOEFF - 2
HODD(z) =
å
n=0
-n
-n
å
n=0
NCOEFF - 1
å
HARBITRARY(z) =
n=0
-SHIFT
GAINEVEN(z) = 2
(13)
-(2 ´ NCOEFF - 2 - n)
COEFFBASE_ADDR + n ´ (z
) + COEFFBASE_ADDR + NCOEFF - 1 ´ z
-2n
-(4 ´ NCOEFF - 6 - 2n)
+z
NCOEFF - 1
) + COEFFBASE_ADDR + NCOEFF - 1 ´ z
COEFFBASE_ADDR + n ´ z
2 ´ NCOEFF - 3
(15)
2´
(16)
NCOEFF - 1
å
n=0
´
COEFFBASE_ADDR + n
15
2 -1
-SHIFT
2´
´
å
n=0
COEFFBASE_ADDR + n + COEFFBASE_ADDR + NCOEFF - 1
15
2 -1
å
-SHIFT
(17)
NCOEFF - 2
´
NCOEFF - 1
GAINARBITRARY(z) = 2
(14)
-n
GAINODD = GAINHALFBAND = 2
24
)
COEFFBASE_ADDR + n ´ (z + z
NCOEFF - 2
HHALFBAND(z) =
-(2 ´ NCOEFF - 1 - n)
COEFFBASE_ADDR + n ´ (z + z
n=0
(18)
COEFFBASE_ADDR + n
15
2 -1
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Extended-Length Filter Mode
NCOEFF - 1
å
-SHIFT
HEXTENDED(z) = 2
´
COEFF_ABASE_ADDR_A + n ´ (z
-2 ´ n
n=0
NCOEFF - 2
å
+
-2 ´ (2 ´ NCOEFF - 1 - n)
+z
-2 ´ n + 1
COEFF_BBASE_ADDR_B + n ´ (z
n=0
+ COEFF_BBASE_ADDR_B + NCOEFF - 1 ´ z
)
+ z-2 ´ (2 ´ NCOEFF - 2 - n) + 1)
2 ´ NCOEFF
(20)
NCOEFF - 1
2´
GAINEXTENDED =
2
-SHIFT
15
´
2 -1
å
COEFF_ABASE_ADDR_A + n
n=0
NCOEFF - 2
+2´
å
n=0
COEFF_BBASE_ADDR_B + n
+ COEFF_BBASE_ADDR_B + NCOEFF - 1
(21)
Digital Downconverter 1 (DDC1)
The description of DDC1 is identical to the description of DDC0, with the following exceptions:
1. DDC1 is enabled by ddc_en[1].
2. Control variables are prefixed with ddc1 instead of ddc0.
3. FIR coefficients are stored in memory banks 3, 4, and 5 instead of 0, 1, and 2.
Table 5 shows the DDC1 operation control settings.
Primary IF Data Interface
The two DDCs produce a total of eight 16-bit output values (I and Q from each of four final-stage FIR filters). The
IF data interface time-multiplexes these eight values onto four serial lines. The IF data interface also generates
the necessary clock and frame sync signals to complete the interface to the DSP. The general timing of the IF
data interface is shown in Figure 15.
Note that each serial line (IF_DOUT0 through IF_DOUT3) can carry up to four time-multiplexed 16-bit signals.
The actual number of signals per line is limited by:
a. the frequency of IF_DCLK, which can be programmed to be the same as the IF sampling clock (MCLK),
one-half the IF sampling frequency, or one-fourth the IF sampling frequency; and
b. the overall decimation ratio of the DDC that determines the frequency of IF_DFSO pulses and therefore the
number of IF_DCLK cycles available to clock out data.
Table 5. IF Control Register Settings
PARAMETER
ADDRESS
BITS
ddc1_cic_dec_rate
21
8:0
ddc1_cic_scale
22
11:6
ddc1_cic_shift
22
5:0
ddc1_demod_freq[31:16]
17
15:0
ddc1_demod_freq[15:0]
18
15:0
ddc1_demod_phase[31:16]
19
15:0
ddc1_demod_phase[15:0]
20
15:0
ddc1_fir1_base_address
23
13:8
ddc1_fir1_mode
23
1:0
ddc1_fir1_ncoeffs
23
7:2
ddc1_fir1_nodec
26
9
ddc1_fir2_nodec
26
10
ddc1_fir2a_base_address
24
15:9
ddc1_fir2a_mode
24
1:0
ddc1_fir2a_ncoeffs
24
8:2
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Table 5. IF Control Register Settings (continued)
ADDRESS
BITS
ddc1_fir2a_shift
PARAMETER
26
3:0
ddc1_fir2b_base_address
25
15:9
ddc1_fir2b_mode
25
1:0
ddc1_fir2b_ncoeffs
25
8:2
ddc1_fir2b_shift
26
7:4
ddc1_interleave
26
8
ddc_en[1]
1
5
ddc_sync
1
6
IF_DCLK
IF_DFSO
IF_DOUT0
A0[15:0]
B0[15:0]
C0[15:0]
D0[15:0]
IF_DOUT1
A1[15:0]
B1[15:0]
C1[15:0]
D1[15:0]
IF_DOUT2
A2[15:0]
B2[15:0]
C2[15:0]
D2[15:0]
IF_DOUT3
A3[15:0]
B3[15:0]
C3[15:0]
D3[15:0]
Figure 15. IF Data General Timing
Control register variables dout0_config, dout1_config, dout2_config, and dout3_config, are used to assign
specific output data streams to particular time slots in the IF interface output frame. Each register is broken into
four 4-bit values, each of which is used to assign the source for a given time slot according to Table 6.
Table 6. Time Slot Sources
VALUE
SOURCE
0
No source assigned
1
DDC0, FIR2A, I
2
DDC0, FIR2A, Q
3
DDC0, FIR2B, I
4
DDC0, FIR2B, Q
5
DDC1, FIR2A, I
6
DDC1, FIR2A, Q
7
DDC1, FIR2B, I
8
DDC1, FIR2B, Q
dout0_config controls the four time slots of IF_DOUT0, register 24 controls the four time slots of IF_DOUT1, and
so on. The mapping of register bits to time slots is summarized in Table 7.
Table 7. Register Bit Mapping
26
PARAMETER
[15:12]
[11:8]
[7:4]
[3:0]
dout0_config
D0
C0
B0
A0
dout1_config
D1
C1
B1
A1
dout2_config
D2
C2
B2
A2
dout3_config
D3
C3
B3
A3
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For example, bits [11:8] of dout2_config set the source assignment for time slot C2 of IF_DOUT2.
The control variable if_dclk_div sets the frequency of IF_DCLK, as shown in Equation 22 and Equation 23.
fMCLK
fIF_DCLK =
if_dclk_div > 1
if_dclk_div
(22)
fIF_DCLK = fMCLK
(23)
if_dclk_div £ 1
Normally the data and the frame sync change on the rising edge of IF_DCLK. If if_dclk_edge is set to 1 then
IF_DCLK is inverted so that data and frame sync change on the falling edge of IF_DCLK.
The control value if_dfso_select determines which DDC is responsible for generating IF_DFSO. If if_dfso_select
is 0, then an IF_DFSO pulse is generated each time a new output is ready from DDC0. Similarly, if if_dfso_select
is 1, then an IF_DFSO pulse is generated each time a new output is ready from DDC1. If the decimation rates of
DDC0 and DDC1 are identical, then it does not matter which DDC initiates the IF_DFSO pulse. If the decimation
rates are different, then the DDC with the smaller decimation ratio (higher output rate) should be chosen to
generate the IF_DFSO pulse. Note that in this case, outputs from the slower DDC are repeated for multiple
frames and it is the responsibility of the DSP software to compensate. This compensation is easiest to do if the
higher decimation rate is an integer multiple of the lower decimation rate.
Finally, if_dfso_mode is used to select alternate forms of frame sync. In the default case (if_dfso_mode = 0), the
frame sync is a high pulse one clock period wide that occurs the clock cycle before the first data bit of the serial
output. If if_dfso_mode is set to 1, then the frame sync changes polarity once per frame; again, one clock cycle
before the first data bit of the frame. If if_dfso_mode is set to 2, then the frame sync behaves like the default
frame sync except that the sync pulse is 16 clock periods wide. The three frame sync modes are illustrated in
Figure 16 and Figure 17. Table 8 shows the detailed timing conditions for Figure 17.
It is recommended that the DSP interface be configured to sample IF_DFSO and the four IF_DOUT lines on the
trailing edge of IF_DCLK. Table 9 shows the dout, if_dclk, if_dfso, and if_dout operation control settings.
Table 8. Detailed Timing Conditions
PARAMETER
MIN
TYP
MAX
tD1
IF_DCLK0 to IF_DFS0 delay
DESCRIPTION
–2.9
0
3.7
UNIT
ns
tD2
IF_DCLK0 to IF_DOUTx delay
–3.1
0
3.8
ns
Table 9. Primary IF Control Register Settings
ADDRESS
BITS
dout_en
PARAMETER
1
7
if_dclk_div
31
4:0
if_dclk_edge
31
5
if_dfso_mode
31
8:7
if_dfso_select
31
6
if_dout0_config
27
15:0
if_dout1_config
28
15:0
if_dout2_config
29
15:0
if_dout3_config
30
15:0
IF_DCLK
IF_DFSO
Mode 0
IF_DFSO
Mode 1
IF_DFSO
Mode 2
IF_DOUT0
A0[15:0]
B0[15:0]
A0[15:0]
B0[15:0]
Figure 16. Frame Sync Modes
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IF_DCLK
td1
IF_DFSO
td2
IF_DOUT0
A0[15]
A0[14]
IF_DOUT1
A1[15]
A1[14]
IF_DOUT2
A2[15]
A2[14]
IF_DOUT3
A3[15]
A3[14]
Figure 17. Detailed Timing
Alternate IF Data Interface
The operation and timing of the alternate IF data interface are identical to the primary IF data interface. Pin
names are changed such that BB_BCK is equivalent to IF_DCLK; BB_WS is equivalent to IF_DFSO;` and
BB_IOUT0, BB_IOUT1, BB_QOUT0, and BB_QOUT1 are each equivalent to any IF_DOUTx pins. The
parameter names are also changed to reflect the different interface pin names. Table 10 shows the BB operation
control settings.
Table 10. Alternate IF Control Register Settings
PARAMETER
ADDRESS
BITS
bb_dclk_edge
36
5
bb_dclk_div
36
4:0
bb_dout0_config
32
15:0
bb_dout1_config
33
15:0
bb_dout2_config
34
15:0
bb_dout3_config
35
15:0
bb_en
1
8
bb_ws_mode
36
10:7
bb_ws_select
36
6
Auxiliary DACs
CDAC0 is enabled by a high value set for cdac_en[0]. Similarly, CDAC1 is enabled by a high value set for
cdac_en[1]. A control DAC that is disabled is put into a low-power state.
The control DAC outputs are set by the control variable cdac0_out for CDAC0 and CDAC1_OUT for CDAC1. A
value of zero generates a 0 output from the control DAC while a value of 4095 generates a full-scale output from
the control DAC. Table 11 shows the CDAC operation control settings.
Table 11. CDAC Control Register Settings
PARAMETER
cdac_en[0]
28
ADDRESS
BITS
1
9
cdac_en[1]
1
10
cdac0_out
37
11:0
cdac1_out
38
11:0
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Auxiliary ADC
The auxiliary ADC is an 8-bit successive approximation converter that is intended for low-speed, low-accuracy
tasks such as system diagnostics. Any one of four input pins can be connected to the auxiliary ADC. The
parameter aux_adc_sel is used to connect a particular input pin to the converter. This input multiplexer operates
according to the following sequence:
• aux_adc_sel = 0:
– No aux ADC inputs are connected, all inputs high impedance
• aux_adc_sel = 1:
– AUX_ADC0 pin connected to aux ADC
• aux_adc_sel = 2:
– AUX_ADC1 pin connected to aux ADC
• aux_adc_sel = 3:
– AUX_ADC2 pin connected to aux ADC
• aux_adc_sel = 4:
– AUX_ADC3 pin connected to aux ADC
A conversion in initiated by writing to register 39 with bit 15 (aux_adc_trig) high. The conversion time is 8704
MCLK cycles. At the end of the conversion auc_adc_done goes high and the result is returned in aux_adc_out.
As an alternative to polling aux_adc_done, the AFE8221 can be configured to generate an interrupt when an
auxiliary ADC conversion is completed. Table 12 shows the aux_adc operation control settings.
Table 12. AUX_ADC Control Register Settings
PARAMETER
ADDRESS
BITS
aux_adc_done
39
15
aux_adc_out
39
7:0
aux_adc_sel
39
11:8
aux_adc_trig
39
15
Master Clock Oscillator
The master clock oscillator supports third-overtone designs from 55 MHz to 75 MHz. It can also support
fundamental operations in the 20-MHz to 30-MHz range. The recommended third-overtone circuit for
third-overtone operation is shown in Figure 18 and Table 13.
51
MCLKO
L1
Crystal
50
MCLKI
R1
AFE8221
1nF
C1
L2
C2
49
DVSS2
Figure 18. Third-Overtone Operation
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Table 13. Third-Overtone Operation Recommendations
FREQUENCY (MHz)
C1
(pF)
C2
(pF)
L1
(µH)
L2
(µH)
R1
(kΩ)
55
3
10
0.1
4.7
6.8
60
5
10
0.82
3.3
4.7
65
4
10
0.68
2.7
3.3
70
5
10
0.56
2.7
3.3
75
3
10
0.56
2.2
3.3
The master clock oscillator may be optionally divided down to provide a reference clock on the REFCLK pin.
Control variable refclk_en enables the generation of the reference clock when high. Two variables, refclk_hi and
refclk_lo, define the high and low periods of REFCLK in terms of MCLK cycles. REFCLK is high for refclk_hi
cycles of MCLK, then low for refclk_lo periods of MCLK. REFCLK frequency is limited to integer submultiples of
MCLK. Table 14 shows the refclk operation control settings.
Table 14. REFCLK Control Register Settings
PARAMETER
ADDRESS
BITS
refclk_en
1
13
refclk_hi
41
15:0
refclk_lo
40
15:0
Real-Time Clock Oscillator
The real-time clock oscillator supports crystals in the frequency range of 32.768 kHz through 150 kHz. The
real-time clock module can be programmed to operate accurately with crystals in this frequency range.
The real-time clock oscillator output may be optionally output on the RTC_OUT pin when rtc_oe is set high. This
option allows the real-time clock oscillator to be used as an alternate reference clock in the event that an
acceptable frequency cannot be derived from MCLK. Table 15 shows the rtc_oe control setting.
Table 15. RTC Control Register Setting
PARAMETER
rtc_oe
ADDRESS
BITS
1
12
I2C Master
The I2C Master interface uses control variables (as shown in Table 16) and two 16-byte buffers to create I2C bus
transactions compliant with the Philips I2C-Bus Specification Version 2.1. Both 7- and 10-bit addressing schemes
are supported. Control variables supply address, data transfer direction, data burst length, and transaction
control information to an I2C master engine. This engine handles the details of the I2C signaling and uses two
16-byte buffers to store data transferred during the transaction. A block diagram for this interface is illustrated in
Figure 19.
SCL clock rates are controlled using the i2cm_clk_cycles control variable given by Equation 24.
fMCLK
fSCL =
4 ´ i2cm_clk_cycles
(24)
The interface supports both standard and fast-mode clock rates of 100 kHz and 400 kHz, respectively. Although
two pairs of SCL and SDA pins are provided, the pins share a common master function. Reprogramming of the
i2cm_if_select variable should only be performed when the i2cm_done status is 1, indicating that all pending I2C
transactions have completed and that it is safe to change the selected pair.
30
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Table 16. I2C Control Register Settings
PARAMETER
ADDRESS
BITS
i2cm_10b_addressing
124
12
i2cm_allow_slave_nack
124
10
i2cm_clear_slave_nack
124
11
i2cm_clk_cycles
124
7:0
i2cm_done
124
15
i2cm_holding
124
14
i2cm_if_sel
121
14
i2cm_multimaster
124
8
i2cm_read_auto_inc
123
15
i2cm_read_byte
123
7:0
i2cm_read_byte_ptr
123
11:8
i2cm_restart_data_length
121
12:8
i2cm_restart_rw
121
13
i2cm_scl_sync_en
124
9
i2cm_slave_addr
120
14:0
i2cm_start_data_length
121
4:0
i2cm_start_rw
121
5
i2cm_use_sr
121
15
i2cm_use_stop
124
13
i2cm_write_auto_inc
122
15
i2cm_write_byte
122
7:0
i2cm_write_byte_ptr
122
11:8
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2
I CM_IF_SEL
Slave
Address
SLAVE_ADDR[14:0]
2
I CM_SLAVE_ADDR[14:0]
SCL
2
I CM_WRITE_BYTE_PTR[3:0]
Write Buffer
Control
2
I CM_WRITE_BYTE[7:0]
2
I CM_WRITE_AUTO_INC
SCL0
2
I C Master Engine
16-Byte
Write
Memory
SCL1
WRITE_DATA[7:0]
SDA0
SDA
SDA1
2
I CM_READ_BYTE_PTR[3:0]
Read Buffer
Control
2
I CM_READ_BYTE[7:0]
2
I CM_READ_BYTE_AUTO_INC
2
I CM_START_DATA_LENGTH[4:0]
2
Slave Burst
Length
I CM_RESTART_DATA_LENGTH[4:0]
2
I CM_USE_SR
2
I CM_START_RW
2
I CM_RESTART_RW
2
I CM_CLK_CYCLES[7:0]
2
READ_DATA[7:0]
START_DATA_LENGTH[4:0]
RESTART_DATA_LENGTH[4:0]
RESTART_RW
USE_SR
START_RW
CLK_CYCLES[7:0]
I CM_MULTIMASTER
MULTIMASTER
2
SCL_SYNC_EN
I CM_SCL_SYNC_EN
2
Transaction
Control
16-Byte
Read
Memory
I CM_ALLOW_SLAVE_NACK
2
I CM_CLEAR_SLAVE_NACK
2
I CM_10B_ADDR
2
I CM_USE_STOP
2
I CM_HOLDING
2
I CM_DONE
ALLOW_SLAVE_NACK
CLEAR_SLAVE_NACK
TEN_BIT_ADDR
USE_STOP
HOLDING
DONE
Figure 19. I2C Master Block Diagram
I2C Write Transactions
Write data must be stored in sequential locations in the write buffer starting at location zero.
i2cm_write_byte_ptr[3:0] specifies one of the 16 memory locations where i2cm_write_byte[7:0] data will be
written. An auto-increment feature permits the internal update of this pointer without specifying an offset for each
byte after the first byte.
Once the desired write data are loaded into this memory, i2cm_start_data_length[4:0] must specify the number of
bytes to write and i2cm_start_rw should be set to 0, indicating that write data will follow the address.
i2cm_10b_addr should be set to select the desired 7- or 10-bit addressing scheme as described in the Control
Register Assignments section of this document.
The write transaction is initiated by writing the slave address to i2cm_slave_addr. The host controller should poll
the i2cm_done bit for a 1, indicating that the transaction has completed. The sequence of actions generated on
the I2C bus are:
Start → Slave Addr → Write Data Burst → Stop
I2C Read Transactions
i2cm_start_data_length[4:0] must specify the number of bytes to read and i2cm_start_rw should be 1, indicating
that read data will follow the address. i2cm_10b_addr specifies the addressing scheme.
The read transaction is initiated by writing the slave address to i2cm_slave_addr. The host controller should poll
the i2cm_done bit for a 1, indicating the transaction has completed. Once completed, the read data can be
extracted from the read buffer using the control variables i2cm_read_ptr[3:0] and i2cm_read_byte[7:0]. The
sequence of actions generated on the bus are:
Start → Slave Addr → Read Data Burst → Stop
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I2C Combined Format Transactions
The I2C specification describes combined write/read formats where a master initially transmits data to a slave
and then reads data from the same slave. The i2cm_use_sr parameter is used to create a repeated START
condition to support this format. By setting the i2cm_use_sr parameter to 1, the master interface can create the
following sequence of actions:
Start → Slave Addr → Data Burst 1 →
Start → Slave Addr → Data Burst 2 → Stop
i2cm_start_data_length[4:0] and i2cm_start_rw control the data burst length and direction for DATA BURST 1.
i2cm_restart_data_length[4:0] and i2cm_restart_rw control the data burst length and direction for DATA BURST
2. If the data direction is the same for both halves of the combined transaction, data are stored sequentially in
the 16-byte buffer. Writing i2cm_slave_addr initiates the transaction.
I2C Data Bursts Greater than 16 Bytes
To create an I2C read or write burst greater than 16 bytes, the i2cm_use_stop parameter should be set to 0,
causing the interface to pause between each burst of bytes transferred. This pause allows the host to either
reload or empty the buffers, depending on the direction of data transfer.
After starting the transaction by writing i2cm_slave_addr, the i2cm_holding status bit should be monitored for a
logic 1, indicating that the interface has completed the current set of byte transfers and is waiting for the host to
continue. After reloading or emptying the buffers as needed, the host should rewrite i2cm_slave_address to
continue the transfer for the next block of up to 16 bytes. For the final transfer of the long data burst,
i2cm_use_stop must be set to 1 prior to re-writing the i2cm_slave_address. This configuration creates a normal
STOP condition to properly terminate the transfer.
Interrupt Operation
As an alternative to polling the values of i2cm_done or i2cm_use_stop, the AFE8221 can be programmed to
generate an interrupt when either of these values goes high.
Real-Time Clock
The real-time clock (RTC) is enabled by setting rtc_en to 1. While rtc_en is 0, the RTC oscillator continues to run
but the RTC registers do not advance.
The RTC can operate with a range of oscillator frequencies up to 100 kHz. At the beginning of each second, 2x
the value of rtc_max_count is loaded into the RTC crystal counter. This counter is decremented at the rate of the
RTC oscillator until it hits zero, which generates a strobe that increments the seconds counter as well as
re-initializes the RTC crystal counter. For a nominal 32.768-kHz clock crystal, rtc_max_count should be set to
16,384 (the default value); for a nominal 100-kHz crystal, rtc_max_count should be set to 50,000. Table 18
illustrates the RTC control variable settings.
The RTC can be coarsely calibrated by adjusting the rtc_max_count to an appropriate value other than half the
nominal crystal frequency. If finer calibration is required, compensation mode can be enabled by setting
rtc_comp_en to 1. In compensation mode, the two's-complement value stored in rtc_comp_val is added to the
one-second counter when it is re-initialized at the beginning of each hour; thus, the first second of each hour is
lengthened or shortened depending on the sign of rtc_comp_val. The compensation can be applied to several
seconds at the beginning of each hour; rtc_comp_cnt holds the number of seconds per hour to which the
compensation is applied. By spreading the compensation out over a number of seconds, the impact on the length
of any given second is minimized.
Setting and Reading the RTC
Because of the need to carefully synchronize any update of the RTC time registers (rtc_seconds, rtc_minutes,
etc.), they must be written in a slightly different manner than the other control registers. Time registers must be
written individually; after a particular register address is written, at least two clock cycles of the RTC oscillator
must pass before another register write occurs. The MSB of each time register address can be polled to
determine if it is safe to make another write: if the MSB is 1, the interface is still busy and a new write should not
be initiated. If the MSB is 0, then the interface is ready to accept another write. There is no limitation on reading
the time registers.
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Note that all time register values are BCD-encoded. Also note that the rtc_day_of_week is a read-only value that
is internally calculated from the rtc_day, rtc_month, and rtc_year registers. Ranges on the various time registers
are shown in Table 17. When the rtc_mode changes, the real-time clock alarm settings should also be changed
to reflect the new time format. For instance, an alarm setting of 1300 hours never generates an interrupt in
12-hour mode. This setting should be reset to 1:00 PM when the mode is changed to 12-hour mode.
Table 17. Time Register Ranges
PARAMETER
RANGE
rtc_seconds
0 to 59
rtc_minutes
0 to 59
rtc_hours
1 to 12 (12-hour mode);
0 to 23 (24-hour mode)
rtc_ampm
0 (AM) or 1 (PM)
12-hour mode only
rtc_day
1 to 31, depending on month
rtc_month
1 to 12
rtc_year
0 to 99
(for years 2000 to 2099)
rtc_day_of_week
0 (Sunday) to 6 (Saturday)
Invalid combinations of rtc_day and rtc_month (trying to set February 30, for example) cause unpredictable
behavior and should be avoided. The February 28/29 rollover variation based on leap year is automatically
corrected for.
The RTC defaults to operate in 12-hour plus AM/PM mode. To operate in 24-hour mode (where the AM/PM bits
are disabled) set rtc_mode to 1. Care must be taken when switching between AM/PM mode and 24-hour mode
to avoid setting the time to a invalid value. See Figure 20 and Figure 21 for the proper procedures.
Real-Time Clock Alarm
The real-time clock alarm function can be used to generate an interrupt (or a wakeup interrupt) at a
pre-programmed time. If the appropriate bit in an interrupt enable register is set, an interrupt will be generated
when the values in the RTC time registers become equal to the values in the RTC alarm registers. The register
settings are shown in Table 18.
Table 18. RTC Alarm Control Register Settings
ADDRESS
BITS
rtc_seconds_alarm[6:0]
PARAMETER
67
6:0
rtc_minutes_alarm[6:0]
68
6:0
rtc_hours_alarm[5:0]
69
5:0
rtc_ampm_alarm
69
7
rtc_day_alarm[5:0]
70
5:0
rtc_month_arlarm[4:0]
71
4:0
rtc_year_alarm[7:0]
72
7:0
GPIO
12 general-purpose I/O pins are provided, labeled GPIO0 through GPIO11. The direction of the 12 GPIO pins
can be independently set through control variable gpio_oe(11:0). A pin is an input if the corresponding bit of
gpio_oe is 0; a pin is an output if the corresponding bit of gpio_oe is 1.
The control variable gpio(11:0) serves different functions, depending on whether it is read from or written to. A
read operation from gpio returns the logic state of the eight GPIO pins regardless of their direction. A write to
gpio sets the output state of the GPIO pins if they are configured as outputs; there is no effect if the pin is
configured as an input. Note that the write value of gpio is stored in a register, so that if a GPIO pin is changed
from an input to an output its logic state is set by the stored value of gpio. Table 21 shows the gpio control
variable settings.
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The GPIO inputs can be optionally debounced if an RTC oscillator is running. Debouncing is controlled by
gpio_delay, which is divided into 12 2-bit fields, each controlling a particular GPIO input according to Table 19.
Table 19. gpio_delay
[23:22]
[21:20]
[19:18]
[17:16]
[15:14]
[13:12]
[11:10]
[9:8]
[7:6]
[5:4]
[3:2]
[1:0]
GPIO11
GPIO10
GPIO9
GPIO8
GPIO7
GPIO6
GPIO5
GPIO4
GPIO3
GPIO2
GPIO1
GPIO0
Begin
Set rtc_mode = 1
Read rtc_hours and
rtc_ampm Registers
12:00AM = 0000 Hours
(Midnight)
Does
rtc_hours = 12 and
rtc_ampm = 0?
Yes
Set rtc_hours = 0
No
Is
rtc_ampm = 0?
(AM)
Yes
No
Does
Yes
rtc_hours = 12 and
rtc_ampm = 1?
12:00 PM = 1200 Hours
(Noon)
No
Set rtc_hours =
rtc_hours + 12
Recalculate
Alarm Registers
Done
Figure 20. Procedure for Updating RTC Hour When Going from 12-Hour Mode to 24-Hour Mode
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Begin
Read rtc_hours Register
(Midnight)
Does
rtc_hours = 0?
Yes
Set rtc_hours = 12
and rtc_ampm = 0
No
(AM)
Is
rtc_hours < 12?
Yes
Set rtc_ampm = 0
No
(Noon)
Does
rtc_hours = 12?
Yes
Set rtc_ampm = 1
No
Set rtc_hours =
rtc_hours - 12
and rtc_ampm = 1
Set rtc_mode = 0
Recalculate
Alarm Registers
Done
Figure 21. Procedure for Updating RTC Hour When Going from 24-Hour Mode to 12-Hour Mode
The debounce circuitry uses a clock divided from the RTC oscillator, with a debounce clock frequency given by
Equation 25.
fRTC
fDEBOUNCE =
2 ´ GPIO_DEBOUNCE_FREQ + 1
2
(25)
If debounce is enabled, then in order for a GPIO input to change value (and possibly generate an interrupt if so
programmed) it must remain stable for the number of debounce clock cycles (zero to three) given in the
appropriate field of gpio_delay.
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Table 20. General RTC Control Register Settings
PARAMETER
ADDRESS
BITS
rtc_ampm
75
7
rtc_comp_cnt[5:0]
64
12:7
rtc_comp_en
64
2
rtc_comp_val
66
15:0
rtc_day[5:0]
76
5:0
rtc_day_of_week[2:0]
79
2:0
rtc_en
64
0
rtc_hours[5:0]
75
5:0
rtc_max_count[15:0]
65
15:0
rtc_minutes[6:0]
74
6:0
rtc_mode
64
1
rtc_month[4:0]
77
4:0
rtc_seconds[6:0]
73
6:0
rtc_year[7:0]
78
7:0
Table 21. GPIO Control Register Settings
ADDRESS
BITS
gpio
PARAMETER
43
11:0
gpio_delay[15:0]
44
15:0
gpio_oe
42
11:0
Alternate Registers (GPIO and Input Attenuator)
If some of the GPIO pins on the AFE8221 are to be used to control the gain of a tuner, it may be desirable to
change the GPIO values at the same time as the input attenuation to the DDC. To make this process more
deterministic, the control parameters gpio, ddc0_atten, and ddc1_atten can be accessed through the alternate
control register addresses of 96 and 97. By writing to register 96, gpio and ddc0_atten can be changed in a
single register write; by writing to register 97, gpio and ddc1_atten can be changed in a single register write.
Table 22 shows the operation control settings for these parameters.
Table 22. Alternate GPIO and DDC Control Register
Settings
PARAMETER
gpio
ADDRESS
96
97
ddc0_atten
96
ddc1_atten
97
BITS
11:0
14:12
Interrupt Generators
There are three programmable interrupt pins; IRQ0, IRQ1, and IRQ2. Only the operation of IRQ0 is described
here; IRQ1 and IRQ2 are programmed in the same way, using different control variables.
Interrupts can be generated from various sources. Interrupt generation is enabled through irq0_en, as Table 23
shows.
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Table 23. Interrupt Generation
BIT POSITION
SOURCE
BIT POSITION
SOURCE
0
GPIO
8
RTC alarm
1
None
9
RTC seconds rollover
2
2
I C Master done
10
RTC minutes rollover
3
Aux ADC done
11
RTC hours rollover
4
IFADC0 over-range
12
RTC months rollover
5
IFADC1 over-range
13
RTC day rollover
6
IFADC0 limit
14
RTC year rollover
7
IFADC1 limit
15
—
Setting a bit of irq0_en allows the generation of an interrupt for the corresponding event. All three IRQ generators
run on the master clock (MCLK). When an interrupt event occurs on a given source signal, a value of 1 is written
to the corresponding bit of irq0_status. This value is held in irq0_status until it is explicitly cleared by writing a 0
to the appropriate bit of irq0_status. A typical sequence upon receipt of an interrupt would be to poll irq0_status
to determine the source of the interrupt, take whatever system action is appropriate, and then clear irq0_status.
Changes to any of the GPIO pins can also be programmed as interrupts. GPIO pin events are defined as
changes from low to high or from high to low, depending on whether the corresponding bit in irq0_gpio_edge is
high or low. GPIO interrupts are enabled by setting the corresponding bit in irq0_gpio_en; they are identified and
cleared by reading and writing the corresponding bit in irq0_gpio_status.
The behavior of the IRQ0 pin is determined by irq0_sense. When irq0_sense is 0, IRQ0 is normally low and goes
high on an unmasked interrupt event. When irq0_sense is 1, IRQ0 is normally high and goes low on an
unmasked interrupt event. Table 24 shows the irq0, irq1, and irq2 operations control settings.
Table 24. IRQ Control Register Settings
PARAMETER
38
ADDRESS
BITS
irq0_en
50
15:0
irq1_en
55
15:0
irq2_en
60
15:0
irq0_gpio_edge
48
11:0
irq1_gpio_edge
53
11:0
irq2_gpio_edge
58
11:0
irq0_gpio_en
49
11:0
irq1_gpio_en
54
11:0
irq2_gpio_en
59
11:0
irq0_gpio_status
52
11:0
irq1_gpio_status
57
11:0
irq2_gpio_status
62
11:0
irq0_sense
2
1
irq1_sense
2
2
irq2_sense
2
3
irq0_status
51
15:0
irq1_status
56
15:0
irq2_status
61
15:0
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Wakeup Interrupt Generator
The WAKEUP interrupt generator functions in the same way as the IRQ generators with the following exceptions:
1. The WAKEUP generator runs on the RTC clock instead of MCLK;
2. The WAKEUP generator operates when the AFE is in low-power mode, whereas the IRQ generators do not;
and
3. The interrupt sources for the WAKEUP interrupt generator are slightly different.
Table 25 shows the wakeup control settings. Table 26 shows the generator functions.
Table 25. Wakeup Control Register Settings
PARAMETER
ADDRESS
BITS
wakeup_sense
2
0
wakeup_gpio_edge
80
11:0
wakeup_gpio_en
81
11:0
wakeup_en
82
15:0
wakeup_status
83
15:0
wakeup_gpio_status
84
11:0
Table 26. WAKEUP Interrupt Generator
BIT POSITION
SOURCE
0
GPIO
1
None
2
None
3
None
4
None
5
None
6
None
7
None
8
RTC alarm
9
RTC seconds rollover
10
RTC minutes rollover
11
RTC hours rollover
12
RTC months rollover
13
RTC day rollover
14
RTC year rollover
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Control Register Assignments
Table 27. Control Registers
Address: 1
Description: Functional Block Enables
Bits
Range
Action
Parameter Name
1:0
0..3
Enable IFADC converters
ifadc_en(1:0)
2
0/1
Gain control for IF_ADC0
ifadc_gain0
3
0/1
Gain control for IF_ADC1
ifadc_gain1
5:4
0..3
Enable DDCs
ddc_en(1:0)
6
0/1
Synchronize DDC0 and DDC1
ddc_sync
7
0/1
Enable primary IF data interface
dout_en
8
0/1
Enable secondary IF data interface
bb_en
10:9
0..3
Enable auxiliary DACs
cdac_en(1:0)
11
0/1
Enable auxiliary ADC
aux_adc_en
12
0/1
Enable RTC output pins
rtc_oe
13
0/1
Enable reference clock output pins
refclk_en
Address: 2
Description: Interrupt Output Level Configuration
Bits
Range
0
0/1
1
0/1
2
0/1
3
0/1
Action
Parameter Name
0 = Active high WAKEUP interrupt
1 = Active low WAKEUP interrupt
0 = Active high IRQ0 interrupt
1 = Active low IRQ0 interrupt
0 = Active high IRQ1 interrupt
1 = Active low IRQ1 interrupt
0 = Active high IRQ2 interrupt
1 = Active low IRQ2 interrupt
wakeup_sense
irq0_sense
irq1_sense
irq2_sense
Address: 3
Description: DDC0 Input Attenuator
Bits
Range
2:0
0..6
Action
Parameter Name
Attenuation setting for DDC0
ddc_atten(2:0)
Address: 4
Description: DDC0 Input Attenuator
Bits
Range
15:0
0..65535
Action
Parameter Name
Delay setting for DDC0 attenuator
ddc0_delay(15:0)
Address: 5
Description: DDC0 NCO Frequency
Bits
Range
15:0
0..65535
Action
Parameter Name
Upper bytes of DDC0 NCO frequency
ddc0_demod_freq(31:16)
Address: 6
Description: DDC0 NCO Frequency
Bits
Range
15:0
0..65535
Action
Parameter Name
Lower bytes of DDC0 NCO frequency
ddc0_demod_freq(15:0)
Address: 7
Description: DDC0 NCO Phase
Bits
Range
15:0
0..65535
40
Action
Parameter Name
Upper bytes of DDC0 NCO phase
ddc0_demod_phase(31:16)
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Table 27. Control Registers (continued)
Address: 8
Description: DDC0 NCO Phase (continued)
Bits
Range
15:0
0..65535
Action
Parameter name
Lower bytes of DDC0 NCO phase
ddc0_demod_phase(15:0)
Address: 9
Description: DDC0 CIC Filter
Bits
Range
Action
Parameter Name
8:0
4..256
CIC filter decimation rate
ddc0_cic_dec_rate(8:0)
Address: 10
Description: DDC0 CIC Filter
Bits
Range
Action
Parameter Name
5:0
11:6
0..63
CIC filter post-filter shift
ddc0_cic_shift(5:0)
0..32
CIC filter post-filter scale
ddc0_cic_scale(5:0)
Address: 11
Description: DDC0 FIR Filter 1
Bits
Range
Action
Parameter Name
1:0
0..3
FIR filter mode
ddc0_fir1_mode(1:0)
7:2
0..63
Number of coefficients to process
ddc0_fir1_ncoeffs(5:0)
13:8
0..63
Coefficient base address
ddc0_fir1_base_addr(5:0)
Address: 12
Description: DDC0 FIR Filter 2A
Bits
Range
1:0
0..3
Action
Parameter Name
FIR filter mode
8:2
ddc0_fir2a_mode(1:0)
0..127
Number of coefficients to process
ddc0_fir2a_ncoeffs(6:0)
15:9
0..127
Coefficient base address
ddc0_fir2a_base_addr(6:0)
Address: 13
Description: DDC0 FIR Filter 2B
Bits
Range
1:0
0..3
Action
Parameter Name
FIR filter mode
8:2
ddc0_fir2b_mode(1:0)
0..127
Number of coefficients to process
15:9
ddc0_fir2b_ncoeffs(6:0)
0..127
Coefficient base address
ddc0_fir2b_base_addr(6:0)
Address: 14
Description: DDC0 FIR Filter Extended Features
Bits
Range
Action
Parameter Name
3:0
7:4
0..15
Post-filter shift for FIR filter 2A
ddc0_fir2a_shift(3:0)
0..15
Post-filter shift for FIR filter 2B
8
ddc0_fir2b_shift(3:0)
0/1
Enable interleave mode for FIR filter 2A and FIR filter 2B
ddc0_interleave
9
0/1
Disable decimation for FIR filter 1
ddc0_fir1_nodec
10
0/1
Disable decimation for FIR filter 2A and FIR filter 2B
ddc0_fir2_nodec
Address: 15
Description: DDC1 Input Attenuator
Bits
Range
2:0
0..6
Action
Parameter Name
Attenuation setting for DDC1
ddc1_atten(2:0)
Address: 16
Description: DDC1 Input Attenuator
Bits
Range
15:0
0..65535
Action
Parameter Name
Delay setting for DDC1 attenuator
ddc1_delay(15:0)
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Table 27. Control Registers (continued)
Address: 17
Description: DDC1 NCO Frequency
Bits
Range
15:0
0..65535
Action
Parameter Name
Upper bytes of DDC1 NCO frequency
ddc1_demod_freq(31:16)
Address: 18
Description: DDC1 NCO Frequency
Bits
Range
15:0
0..65535
Action
Parameter Name
Lower bytes of DDC1 NCO frequency
ddc1_demod_freq(15:0)
Address: 19
Description: DDC1 NCO Phase
Bits
Range
15:0
0..65535
Action
Parameter Name
Upper bytes of DDC1 NCO phase
ddc1_demod_phase(31:16)
Address: 20
Description: DDC1 NCO Phase
Bits
Range
15:0
0..65536
Action
Parameter Name
Lower bytes of DDC1 NCO phase
ddc1_demod_phase(15:0)
Address: 21
Description: DDC1 CIC Filter Decimation
Bits
Range
Action
Parameter Name
8:0
4..256
CIC filter decimation rate
ddc1_cic_dec_rate(8:0)
Address: 22
Description: DDC1 CIC Filter
Bits
Range
Action
Parameter Name
5:0
0..63
CIC filter post-filter shift
ddc1_cic_shift(5:0)
11:6
0..32
CIC filter post-filter scale
ddc1_cic_scale(5:0)
Address: 23
Description: DDC1 FIR Filter 1
Bits
Range
Action
Parameter Name
1:0
0..3
FIR filter mode
ddc1_fir1_mode(1:0)
7:2
0..63
Number of coefficients to process
ddc1_fir1_ncoeffs(5:0)
13:8
0..63
Coefficient base address
ddc1_fir1_base_addr(5:0)
Address: 24
Description: DDC1 FIR Filter 2A
Bits
Range
Action
Parameter Name
1:0
0..3
FIR filter mode
ddc1_fir2a_mode(1:0)
8:2
0..127
Number of coefficients to process
ddc1_fir2a_ncoeffs(6:0)
15:9
0..127
Coefficient base address
ddc1_fir2a_base_addr(6:0)
Address: 25
Description: DDC1 FIR Filter 2B
Bits
Range
1:0
0..3
8:2
15:9
42
Action
Parameter Name
FIR filter mode
ddc1_fir2b_mode(1:0)
0..127
Number of coefficients to process
ddc1_fir2b_ncoeffs(6:0)
0..127
Coefficient base address
ddc1_fir2b_base_addr(6:0)
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Table 27. Control Registers (continued)
Address: 26
Description: DDC1 FIR Filter Extended Features
Bits
Range
Action
Parameter Name
3:0
0..15
Post-filter shift for FIR filter 2A
ddc1_fir2a_shift(3:0)
7:4
0..15
Post-filter shift for FIR filter 2B
ddc1_fir2b_shift(3:0)
8
0/1
Enable interleave mode for FIR filter 2A and FIR filter 2B
ddc1_interleave
9
0/1
Disable decimation for FIR filter 1
ddc1_fir1_nodec
10
0/1
Disable decimation for FIR filter 2A and FIR filter 2B
ddc1_fir2_nodec
Address: 27
Description: Data Interface Configuration
Bits
Range
15:0
0..65535
Action
Parameter Name
Configuration for IF_DOUT0
if_dout0_config
Address: 28
Description: Data Interface Configuration
Bits
Range
15:0
0..65535
Action
Parameter Name
Configuration for IF_DOUT1
if_dout1_config
Address: 29
Description Data Interface Configuration
Bits
Range
15:0
0..65535
Action
Parameter Name
Configuration for IF_DOUT2
if_dout2_config
Address: 30
Description: Data Interface Configuration
Bits
Range
15:0
0..65535
Action
Parameter Name
Configuration for IF_DOUT3
if_dout3_config
Address: 31
Description: Data Interface Configuration
Bits
Range
4:0
0..16
5
0/1
6
0/1
8:7
0..2
Action
Parameter Name
Divide factor to derive IF_DCLK from MCLK
if_dclk_div(4:0)
0: IF_DFSO and IF_DOUTx change on rising edge of IF_DCLK
1: IF_DFSO and IF_DOUTx change on falling edge of IF_DCLK
0: IF_DFSO generated by DDC0
1: IF_DFSO generated by DDC1
if_dclk_edge
if_dfso_select
0: IF_DFSO one IF_DCLK cycle wide
1: IF_DFSO toggles once per frame
if_dfso_mode(1:0)
2: IF_DFSO 16 IF_DCLK cycles wide
Address: 32
Description: Data Interface Configuration
Bits
Range
15:0
0..65535
Action
Parameter Name
Configuration for BB_DOUT0
bb_dout0_config
Address: 33
Description: Data Interface Configuration
Bits
Range
15:0
0..65535
Action
Parameter Name
Configuration for BB_DOUT1
bb_dout1_config
Address: 34
Description: Data Interface Configuration
Bits
Range
15:0
0..65535
Action
Parameter Name
Configuration for BB_DOUT2
bb_dout2_config
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Table 27. Control Registers (continued)
Address: 35
Description: Data Interface Configuration (continued)
Bits
Range
15:0
0..65535
Action
Parameter Name
Configuration for BB_DOUT3
bb_dout3_config
Address: 36
Description: Data Interface Configuration
Bits
Range
4:0
0..16
5
0/1
6
0/1
8:7
0..2
Action
Parameter Name
Divide factor to derive BB_BCK from MCLK
bb_bck_div(4:0)
0: BB_WS and BB_DOUTx change on rising edge of BB_BCK
1: BB_WS and BB_DOUTx change on falling edge of BB_BCK
0: BB_WS generated by DDC0
bb_bck_edge
bb_ws_select
1: BB_WS generated by DDC1
0: BB_WS one BB_BCK cycle wide
1: BB_WS toggles once per frame
bb_ws_mode(1:0)
2: BB_WS 16 BB_BCK cycles wide
Address: 37
Description: CDAC0 Output
Bits
Range
Action
Parameter Name
11:0
0..4095
Output value for CDAC0
cdac0_out(11:0)
Address: 38
Description: CDAC1 Output
Bits
Range
Action
Parameter Name
11:0
0..4095
Output value for CDAC1
cdac1_out(11:0)
Address: 39
Description: Aux ADC
Bits
Range
Action
Parameter Name
7:0
0..255
Register read: Conversion result for auxiliary ADC (read only)
aux_adc_out(7:0)
0: No aux ADC inputs connected
1: AUX_ADC0 pin connected to aux ADC
11:8
0, 1, 2, 4, or 8
2: AUX_ADC1 pin connected to aux ADC
aux_adc_sel(3:0)
4: AUX_ADC2 pin connected to aux ADC
8: AUX_ADC3 pin connected to aux ADC
14:12
Not used
Register write: Starts a conversion when 1 is written
15
0/1
Register read: Returns 0 while conversion is in progress, 1 when
conversion is finished
aux_adc_done
Address: 40
Description: Reference Clock Configuration
Bits
Range
Action
Parameter Name
15:0
0..4095
Low period ( in units of MCLK cycles) for reference clock output
refclk_lo(15:0)
Address: 41
Description: Reference Clock Configuration
Bits
Range
Action
Parameter Name
15:0
0..4095
High period (in units of MCLK cycles) for reference clock output
refclk_hi(15:0)
44
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Table 27. Control Registers (continued)
Address: 42
Description: GPIO Configuration
Bits
Range
0
0/1
1
0/1
2
0/1
3
0/1
4
0/1
5
0/1
6
0/1
7
0/1
8
0/1
9
0/1
10
0/1
11
0/1
Action
Parameter Name
0 = GPIO0 set as input
1 = GPIO0 set as output
0 = GPIO1 set as input
1 = GPIO1 set as output
0 = GPIO2 set as input
1 = GPIO2 set as output
0 = GPIO3 set as input
1 = GPIO3 set as output
0 = GPIO4 set as input
1 = GPIO4 set as output
0 = GPIO5 set as input
1 = GPIO5 set as output
0 = GPIO6 set as input
1 = GPIO6 set as output
0 = GPIO7 set as input
1 = GPIO7 set as output
0 = GPIO8 set as input
1 = GPIO8 set as output
0 = GPIO9 set as input
1 = GPIO9 set as output
0 = GPIO10 set as input
1 = GPIO10 set as output
0 = GPIO11 set as input
1 = GPIO11 set as output
gpio_oe(0)
gpio_oe(1)
gpio_oe(2)
gpio_oe(3)
gpio_oe(4)
gpio_oe(5)
gpio_oe(6)
gpio_oe(7)
gpio_oe(8)
gpio_oe(9)
gpio_oe(10)
gpio_oe(11)
Address: 43
Description: GPIO Configuration (continued)
Bits
Range
0
0/1
1
0/1
2
0/1
3
0/1
4
0/1
5
0/1
6
0/1
7
0/1
8
0/1
Action
Parameter Name
Register write: drives value on GPIO0 pin if enabled as output
Register read: returns value on GPIO0 pin
Register write: drives value on GPIO1 pin if enabled as output
Register read: returns value on GPIO1 pin
Register write: drives value on GPIO2 pin if enabled as output
Register read: returns value on GPIO2 pin
Register write: drives value on GPIO3 pin if enabled as output
Register read: returns value on GPIO3 pin
Register write: drives value on GPIO4 pin if enabled as output
Register read: returns value on GPIO4 pin
Register write: drives value on GPIO5 pin if enabled as output
Register read: returns value on GPIO5 pin
Register write: drives value on GPIO6 pin if enabled as output
Register read: returns value on GPIO6 pin
Register write: drives value on GPIO7 pin if enabled as output
Register read: returns value on GPIO7 pin
Register write: drives value on GPIO8 pin if enabled as output
Register read: returns value on GPIO8 pin
gpio(0)
gpio(1)
gpio(2)
gpio(3)
gpio(4)
gpio(5)
gpio(6)
gpio(7)
gpio(8)
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Table 27. Control Registers (continued)
9
0/1
10
0/1
11
0/1
Register write: drives value on GPIO9 pin if enabled as output
gpio(9)
Register read: returns value on GPIO9 pin
Register write: drives value on GPIO10 pin if enabled as output
Register read: returns value on GPIO10 pin
Register write: drives value on GPIO11 pin if enabled as output
Register read: returns value on GPIO11 pin
gpio(10)
gpio(11)
Address: 44
Description: GPIO Configuration
Bits
Range
Action
Parameter Name
1:0
0..3
GPIO0 debounce setting
gpio_delay(1:0)
3:2
0..3
GPIO1 debounce setting
gpio_delay(3:2)
5:4
0..3
GPIO2 debounce setting
gpio_delay(5:4)
7:6
0..3
GPIO3 debounce setting
gpio_delay(7:6)
9:8
0..3
GPIO4 debounce setting
gpio_delay(9:8)
11:10
0..3
GPIO5 debounce setting
gpio_delay(11:10)
13:12
0..3
GPIO6 debounce setting
gpio_delay(13:12)
15:14
0..3
GPIO7 debounce setting
gpio_delay(15:14)
Address: 45
Description: GPIO Configuration
Bits
Range
Action
Parameter Name
1:0
0..3
GPIO8 debounce setting
gpio_delay(17:16)
3:2
0..3
GPIO9 debounce setting
gpio_delay(19:18)
5:4
0..3
GPIO10 debounce setting
gpio_delay(21:20)
7:6
0..3
GPIO11 debounce setting
gpio_delay(23:22)
Address: 46
Description: IF ADC Alarm
Bits
Range
Action
Parameter Name
11:0
0..2047
Alarm limit for IF_ADC0
ifadc0_limit(11:0)
Address: 47
Description: IF ADC Alarm
Bits
Range
Action
Parameter Name
11:0
0..2047
Alarm limit for IF_ADC1
ifadc1_limit(11:0)
Address: 48
Description: IRQ0 Configuration
Bits
Range
Action
Parameter Name
11:0
0..4095
GPIO input edge select for IRQ0
irq0_gpio_edge(11:0)
Address: 49
Description: IRQ0 Configuration
Bits
Range
Action
Parameter Name
11:0
0..4095
IRQ0 GPIO enable
irq0_gpio_en(11:0)
Address: 50
Description: IRQ0 Configuration
Bits
Range
15:0
0..65535
46
Action
Parameter Name
IRQ0 enable
irq0_en(15:0)
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Table 27. Control Registers (continued)
Address: 51
Description: IRQ0 Status
Bits
15:0
Range
0..65535
Action
Parameter Name
Register read: returns IRQ0 status
Register write: clears interrupt bit if 1 is written
irq0_status(15:0)
Address: 52
Description: IRQ0 GPIO Status
Bits
11:0
Range
0..4095
Action
Parameter Name
Register read: returns IRQ0 status
Register write: clears interrupt bit if 1 is written
irq0_gpio_status(11:0)
Address: 53
Description: IRQ1 Configuration
Bits
Range
Action
Parameter Name
11:0
0..4095
GPIO input edge select for IRQ1
irq1_gpio_edge(11:0)
Address: 54
Description: IRQ1 Configuration
Bits
Range
Action
Parameter Name
11:0
0..4095
IRQ1 GPIO enable
irq1_gpio_en(11:0)
Address: 55
Description: IRQ1 Configuration
Bits
Range
15:0
0..65535
Action
Parameter Name
IRQ1 enable
irq1_en(15:0)
Address: 56
Description: IRQ1 Status
Bits
15:0
Range
0..65535
Action
Parameter Name
Register read: returns IRQ1 status
Register write: clears interrupt bit if 1 is written
irq1_status(15:0)
Address: 57
Description: IRQ1 GPIO Status (continued)
Bits
11:0
Range
0..4095
Action
Parameter Name
Register read: returns IRQ1 status
Register write: clears interrupt bit if 1 is written
irq1_gpio_status(11:0)
Address: 58
Description: IRQ2 Configuration
Bits
Range
Action
Parameter Name
11:0
0..4095
GPIO input edge select for IRQ2
irq2_gpio_edge(11:0)
Address: 59
Description: IRQ2 Configuration
Bits
Range
Action
Parameter Name
11:0
0..4095
IRQ2 GPIO enable
irq2_gpio_en(11:0)
Address: 60
Description: IRQ2 Configuration
Bits
Range
15:0
0..65535
Action
Parameter Name
IRQ2 enable
irq2_en(15:0)
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Table 27. Control Registers (continued)
Address: 61
Description: IRQ2 Status
Bits
15:0
Range
0..65535
Action
Parameter Name
Register read: returns IRQ2 status
irq2_status(15:0)
Register write: clears interrupt bit if 1 is written
Address: 62
Description: IRQ2 GPIO Status
Bits
11:0
Range
0..4095
Action
Parameter Name
Register read: returns IRQ2 status
irq2_gpio_status(11:0)
Register write: clears interrupt bit if 1 is written
Address: 63
Description: Not Used
Bits
Range
—
—
Action
Parameter Name
—
—
Address: 64
Description: Real-Time Clock Configuration
Bits
Range
Action
Parameter Name
0
0/1
1
0/1
2
0/1
Enable clock compensation
rtc_comp_en
3
0/1
Enable clock test mode
rtc_test_en
6:4
0..4
Clock test mode selection
rtc_test_mode(2:0)
12:7
0..31
Compensation count
rtc_comp_cnt(5:0)
15:13
0..7
Frequency select for GPIO debounce
gpio_debounce_freq(2:0)
0 = Freeze real-time clock
rtc_en
1 = Enable real-time clock operation
0:12 hour mode
rtc_mode
1:24 hour mode
Address: 65
Description: Real-Time Clock Configuration
Bits
Range
15:0
0..32767
Action
Parameter Name
Real-time one second terminal count. Default = 16384 (for 32.768-kHz
crystal)
rtc_max_count(15:0)
Address: 66
Description: Real-Time Clock Configuration (continued)
Bits
Range
15:0
–32768..32767
Action
Parameter Name
Real-time clock compensation value. Default = 16384
rtc_comp_val(15:0)
Address: 67
Description: Real-Time Clock Alarm
Bits
Range
6:0
0..59
Action
Parameter Name
Seconds alarm setting
rtc_seconds_alarm(6:0)
Address: 68
Description: Real-Time Clock Alarm
Bits
Range
6:0
0..59
48
Action
Parameter Name
Minutes alarm setting
rtc_minutes_alarm(6:0)
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Table 27. Control Registers (continued)
Address: 69
Description: Realtime Clock Alarm
Bits
5:0
6
7
Range
Action
Parameter Name
1..12
Hour alarm setting, 12-hour mode
0..23
Hour alarm setting, 24-hour mode
—
Not used
—
12-hour mode: 0 = AM, 1 = PM
0/1
rtc_hours_alarm(5:0)
24-hour mode: not used
rtc_ampm_alarm
Address: 70
Description: Real-Time Clock Alarm
Bits
Range
5:0
1..31
Action
Parameter Name
Day of the month alarm setting
rtc_day_alarm(5:0)
Address: 71
Description: Real-Time Clock Alarm
Bits
Range
4:0
1..12
Action
Parameter Name
Month alarm setting
rtc_months_alarm(4:0)
Address: 72
Description: Real-Time Clock Alarm
Bits
Range
7:0
0..99
Action
Parameter Name
Year alarm setting
rtc_year_alarm(7:0)
Address: 73
Description: Real-Time Clock Current Time
Bits
Range
6:0
0..59
Action
Parameter Name
Seconds register
rtc_seconds(6:0)
14:7
—
Not used
—
15
0/1
Real-time clock busy (read only)
rtc_busy
Address: 74
Description: Real-Time Clock Current Time
Bits
Range
6:0
0..59
14:7
—
15
0/1
Action
Parameter Name
Minutes register
rtc_minutes(6:0)
Not used
—
Real-time clock busy (read only)
rtc_busy
Address: 75
Description: Real-Time Clock Current Time (continued)
Bits
5:0
6
Range
Action
Parameter Name
1..12
Hour register, 12-hour mode
0..23
Hour register, 24-hour mode
—
7
0/1
14:8
—
15
0/1
Not used
rtc_hours(5:0)
—
12-hour mode: 0 = AM, 1 = PM
24-hour mode: not used
rtc_ampm
Not used
—
Real-time clock busy (read only)
rtc_busy
Address: 76
Description: Real-Time Clock Current Time
Bits
Range
5:0
1..31
Action
Parameter Name
Day of month register
14:6
rtc_day(5:0)
—
Not used
—
15
0/1
Real-time clock busy (read only)
rtc_busy
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Table 27. Control Registers (continued)
Address: 77
Description: Real-Time Clock Current Time
Bits
Range
4:0
1..12
Action
Parameter Name
Month register
rtc_month(4:0)
14:5
—
Not used
—
15
0/1
Real-time clock busy (read only)
rtc_busy
Address: 78
Description: Real-Time Clock Current Time
Bits
Range
7:0
0..99
14:8
—
15
0/1
Action
Parameter Name
Year register
rtc_year(7:0)
Not used
—
Real-time clock busy (read only)
rtc_busy
Address: 79
Description: Real-Time Clock Current Time
Bits
Range
2:0
0..6
14:3
—
15
0/1
Action
Parameter Name
Day of week
rtc_day_of_week(2:0)
Not used
—
Real-time clock busy (read only)
rtc_busy
Address: 80
Description: WAKEUP Configuration
Bits
Range
Action
Parameter Name
11:0
0..4095
GPIO input edge select for WAKEUP
wakeup_gpio_edge(11:0)
Address: 81
Description: WAKEUP Configuration
Bits
Range
Action
Parameter Name
11:0
0..4095
WAKEUP GPIO enable
wakeup_gpio_en(11:0)
Address: 82
Description: WAKEUP Configuration
Bits
Range
15:0
0..65535
Action
Parameter Name
WAKEUP enable
wakeup_en(15:0)
Address: 83
Description: WAKEUP Status
Bits
15:0
Range
0..65535
Action
Parameter Name
Register read: returns WAKEUP status
Register write: clears interrupt bit if 1 is written
wakeup_status(15:0)
Address: 84
Description: WAKEUP GPIO Status
Bits
11:0
Range
0..4095
Action
Parameter Name
Register read: returns WAKEUP status
Register write: clears interrupt bit if 1 is written
wakeup_gpio_status(11:0)
Address: 85–119
Description: Not Used
Bits
Range
—
—
50
Action
Parameter Name
—
—
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Table 27. Control Registers (continued)
Address: 120
Description: I2C Master—Slave Address
Bits
Range
Action
Parameter Name
Slave address used for master transactions. Also starts transaction.
14:0
0..32767
7-bit addressing: bits 6:0 are the slave address. Bits 14:7 are ignored.
i2cm_slave_addr(14:0)
10-bit addressing: bits 9:0 are the slave address. Bits 14:10 are the
upper five bits for the slave address first byte
15
—
Not used
—
Address: 121
Description: I2C Master—Slave Burst length
Bits
Range
4:0
1..16
Action
Parameter Name
Number of bytes to transfer for the first data burst
i2cm_start_data_length(4:0)
Selects the Read/Write bit value used with the slave address following
START.
5
0/1
7:6
—
i2cm_start_rw
0 selects Write
1 selects Read
12:8
1..16
Not used
—
Number of bytes to transfer for the second data burst in a combined
format transfer. This parameter is used only if i2cm_use_sr = 1.
i2cm_restart_data_length(4:0)
Selects the Read/Write bit value used with the slave address following
RESTART.
13
0/1
i2cm_restart_rw
0 selects Write
1 selects Read
14
0/1
15
0/1
0 = SDA0/SCL0 interface
i2xm_if_sel
1 = SDA1/SCL1 interface
0 selects I2C transactions without a repeated start.
i2cm_use_sr
1 selects combined transactions with a repeated start.
Address: 122
Description: I2C Master—Write Buffer Control
Bits
Range
Action
Parameter Name
7:0
0..255
Stores data in the write buffer at the location specified by
i2cm_write_byte_ptr(3:0)
i2cm_write_byte(7:0)
11:8
0..15
Buffer location where the i2cm_write_byte should be placed
i2cm_write_byte_ptr(3:0)
14:12
—
Not used
—
Auto increment
15
0 = i2cm_write_byte_ptr is used for storing the i2cm_write_byte value
in the write buffer memory
0/1
i2cm_write_auto_inc
1 = i2cm_write_byte_ptr is ignored from the host and it is
auto-incremented for writing the i2cm_write_byte to the buffer
Address: 123
Description: I2C Master—Read Buffer Control
Bits
Range
Action
Parameter Name
2
7:0
0..255
Read only - retrieves data read by the I C master from the read buffer
i2cm_read_byte(7:0)
11:8
0..15
Buffer location where the i2cm_read_byte should be retrieved
i2cm_read_byte_ptr(3:0)
14:12
—
Not used
—
Auto increment
15
0/1
0 = i2cm_read_byte_ptr is used for retrieving the i2cm_write_byte
value in the read buffer memory
i2cm_read_auto_inc
1 = i2cm_read_byte_ptr is ignored from the host and it is
auto-incremented for retrieving the i2cm_read_byte from the buffer
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Table 27. Control Registers (continued)
Address: 124
Description: I2C Master—Read Buffer Control
Bits
Range
7:0
5 to 200
8
0/1
Action
Parameter Name
Controls the I2C SCL clock rate
i2cm_clk_cycles(7:0)
Multi-master
0 = single I2C master on SDA and SCL signals
i2cm_multimaster
1 = multiple I2C masters present on SDA and SCL signals
SCL sync enable
9
0/1
0 = prohibit SCL stretching by slave
i2cm_scl_sync_en
1 = permit SCL stretching by slave
Allow slave NACK
10
0/1
0 = require slave to ACK transfers
i2cm_allow_slave_nack
1 = permit slave to not-acknowledge (NACK)
11
0/1
12
0/1
Clear slave NACK. if i2cm_allow_slave_nack is zero and the slave fails
to acknowledge, this bit when read will be set. No further I2C
i2cm_clear_slave_nack
transactions are allowed until this bit is written as a 1 to clear the slave
NACK condition.
0 = Use 7 bit addressing
i2cm_10b_addressing
1 = Use 10 bit addressing
End transfer with stop
0 = do not issue a stop after last byte transferred and pause
transaction
13
0/1
i2cm_use_stop
14
0/1
Holding. Read-only. Used when i2cm_use_stop is set to zero.
i2cm_holding
0/1
Done. Read-only. When set, the I2C master has completed any
pending transactions.
i2cm_done
1 = issue a stop after the last byte transferred
15
52
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MECHANICAL DATA
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Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): AFE8221-Q1
PACKAGE OPTION ADDENDUM
www.ti.com
13-Jan-2009
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
AFE8221IRFPQ1
ACTIVE
HTQFP
RFP
Pins Package Eco Plan (2)
Qty
144
60
Green (RoHS &
no Sb/Br)
Lead/Ball Finish
CU NIPDAU
MSL Peak Temp (3)
Level-3-260C-168 HR
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS
compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is
provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the
accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take
reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on
incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited
information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI
to Customer on an annual basis.
OTHER QUALIFIED VERSIONS OF AFE8221-Q1 :
• Catalog: AFE8221
NOTE: Qualified Version Definitions:
• Catalog - TI's standard catalog product
Addendum-Page 1
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