FREESCALE MCZ33784EF/R2-

Freescale Semiconductor
Advance Information
Document Number: MC33784
Rev 3.0, 11/2009
DSI 2.02 Sensor Interface
33784
The 33784 is a slave, Distributed System Interface Bus (DBUS),
version 2.02 compatible device, optimized as a sensor interface. The
device contains circuits to power sensors such as accelerometers,
and to digitize the analog level from the sensor. The device is
controlled by commands over the bus, and returns measured data
and other information over the bus.
SENSOR INTERFACE
Features
•
•
•
•
•
•
•
DSI version 2.02 compatible
2-channel, 10-bit analog-to-digital converter (ADC)
3 pins configurable as logic inputs or outputs
Provides regulated +5.0v output for sensor power from bus
On-board clock (no external elements required)
Includes bus switches on bus and bus return
Pb-free packaging designated by suffix code EF
EF SUFFIX (PB-FREE)
98ASB42566B
16-LEAD SOICN
ORDERING INFORMATION
33781
Device
Temperature
Range (TA)
Package
MCZ33784EF/R2
- 40°C to 125°C
16 SOICN
33784
33784
BUS
REGOUT
RTNIN
AGND
BUSOUT
BUSIN
BUSOUT
RTNOUT
RTNIN
RTNOUT
AN0
BUSIN
AN1
H_CAP
I/O0
I/O1
I/O2
IDDQ
TEST1
TOUT
TEST2
VCC
XY
ACCELEROMETER
AGND
Figure 1. 33784 Simplified Application Diagram
(Daisy Chain Shown)
* This document contains certain information on a new product.
Specifications and information herein are subject to change without notice.
© Freescale Semiconductor, Inc., 2008 - 2009. All rights reserved.
To other
33784
Slaves
INTERNAL BLOCK DIAGRAM
INTERNAL BLOCK DIAGRAM
H_CAP
2.2μF or
4.7μF
Typical
Rectifier
BUSIN
High Side Bus Switch
0-35 V
BUSOUT
Receiver
Data
Response
Current
0–11mA
8.0mA/μs
Frame
Received
Message
from MCU
Bandgap
Reference
Oscillator
10MHz
DataOut <2.0>
Bus Return
Logic
Command Decode
State Machine
Response Generation
I/O Buffers
DataOut <0>
I/O0
Power
Management
5.0V Regulator
BG Reference
Bias Currents
DataOut <1>
I/O1
I/O2
DataOut <2>
REGOUT
CRO = 2.2μF
AGND
SEL
POR
10-Bit
ADC
TEST1
TEST2
TOUT
IDDQ
MUX
AN0
AN1
RTNIN
Low Side Bus Switch
RTNOUT
Figure 2. 33784 Simplified Internal Block Diagram
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Analog Integrated Circuit Device Data
Freescale Semiconductor
PIN CONNECTIONS
PIN CONNECTIONS
REGOUT
1
16
H_CAP
TEST2
2
15
BUSIN
I/O0
3
14
BUSOUT
I/O1
4
13
RTNIN
I/O2
5
12
RTNOUT
AN0
6
11
TOUT
AGND
7
10
IDDQ
AN1
8
9
TEST1
Figure 3. 33784 Pin Connections
Table 1. 33784 Pin Definitions
A functional description of each pin can be found in the Functional Pin Description section beginning on page 10.
Pin Number
Pin Name
Pin
Function
1
REGOUT
2
Formal Name
Definition
Output
Regulator
Output
Pin provides a regulated 5.0V output. The power is derived from the bus.
TEST2
Test
Test2
3
4
5
I/O0
I/O1
I/O2
Input/Output
Logic I/O
6, 8
AN0,AN1
Input
Analog Input
7
AGND
Ground
Reference
Analog Ground
9
TEST1
Test
Test1
This pin must be grounded in the application.
10
IDDQ
Test
IDDQ
Input pin for measuring device quiescent current. Must be left open in the
application.
11
TOUT
Test
Test Output
This pin must be grounded in the application.
12
RTNOUT
Power
Bus Return
Switched RTNIN pin, attaches to the next RTNIN pin in the daisy chain.
13
RTNIN
Power
Bus Return
Pin attaches to the low side of the differential bus, and provides the common
return for power and signalling. It is internally connected to AGND.
14
BUSOUT
Output
DBUS Output
15
BUSIN
Input
DBUS Input
16
H_CAP
Output
Holding
Capacitor
This pin must be grounded in the application.
Pins can be used to provide a logic level output or a logic input.
Inputs to the ADC.
Pin is the low reference level and power return for the analog-to-digital
converter (ADC). It is internally connected to RTNIN.
Switched BUSIN Pin, attaches to the next BUSIN pin in the daisy chain.
Pin attaches to the high side of the differential bus and responds to
initialization commands.
A capacitor attached to this pin is charged by the bus during bus idle and
supplies current to run the device and for external devices via the REGOUT
pin during non-idle periods.
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Freescale Semiconductor
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ELECTRICAL CHARACTERISTICS
MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
MAXIMUM RATINGS
Table 2. Maximum Ratings
All voltages are with respect to Analog Ground (AGND) unless otherwise noted. Exceeding these ratings may cause a
malfunction or permanent damage to the device.
Ratings
Symbol
Value
Unit
I /O0, I/O1, I/O2, AN0, AN1, TEST1, TEST2, TOUT Voltage
VIO
-0.3 to VREGOUT + 0.3
V
I /On, ANn, TESTn, TOUT Pin Current
IIO
5.0
mA
BUSOUT Voltage, BUS SW = open
VIN
-14 to 40
V
BUSIN Voltage, BUS SW = open
VIN
-0.3 to 40
V
RTNOUT Voltage, BUS SW = open
VIN
-14 to 25
V
H_CAP Voltage
VIN
-0.3 to 40
V
BUSIN, BUSOUT, and H_CAP Current (Continuous)
IIN
400
mA
IREVLK
400
mA
IBUSRTN
400
mA
VIDDQ
2.75
V
VRO
0.3 - 7.0
V
ELECTRICAL RATINGS
BUSIN, RTNIN, reverse current (max 5 ms)
RTNIN, RTNOUT Current
IDDQ Voltage
VREG Range
ESD
Voltage(1)
VESD
V
Human Body Model (HBM)
±2000
Machine Model (MM)
±200
Charge Device Model (CDM)
Corner pins
±750
All other pins
±500
THERMAL RATINGS
Storage Temperature
TS
-55 to 150
°C
Operating Ambient Temperature
TA
-40 to 125
°C
Operating Junction Temperature
TJ
-40 to 150
°C
Resistance, Junction-to-Ambient (Single Layer (1s) PCB Board)
RθJA
125
°C/W
Resistance, Junction-to-Board (Multi-Layer (2s2P) PCB Board)
RθJB
62
°C/W
TPPRT
Note 3
°C
THERMAL RESISTANCE AND PACKAGE DISSIPATION RATINGS
(2) (3)
Peak Package Reflow Temperature During Reflow ,
Notes
1. ESD1 testing is performed in accordance with the Human Body Model (HBM) (CZAP = 100pF, RZAP = 1500Ω), ESD2 testing is
performed in accordance with the Machine Model (MM) (CZAP = 200pF, RZAP = 0Ω); and Charge Body Model (CBM)
2.
3.
Pin soldering temperature limit is for 10 seconds maximum duration. Not designed for immersion soldering. Exceeding these limits may
cause malfunction or permanent damage to the device.
Freescale’s Package Reflow capability meets Pb-free requirements for JEDEC standard J-STD-020C. For Peak Package Reflow
Temperature and Moisture Sensitivity Levels (MSL), Go to www.freescale.com, search by part number [e.g. remove prefixes/suffixes
and enter the core ID to view all orderable parts. (i.e. MC33xxxD enter 33xxx), and review parametrics.
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Analog Integrated Circuit Device Data
Freescale Semiconductor
ELECTRICAL CHARACTERISTICS
STATIC ELECTRICAL CHARACTERISTICS
STATIC ELECTRICAL CHARACTERISTICS
Table 3. Static Electrical Characteristics
Characteristics noted under conditions -0.3V ≤ VBUSIN ≤ 30V, 6.0V ≤ VH_CAP ≤ 30V, - 40°C ≤ TA ≤ 125°C,
RTNIN=AGND = 0V, unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25°C under
nominal conditions, unless otherwise noted.
Characteristic
Internal Quiescent Current Drain
Symbol
Min
Typ
Max
IQ
VH_CAP = 25V, I /O = Input
mA
–
–
4.0
–
0.75
1.00
–
0.9
1.4
99
–
–
VBUSIN = 8.0V, VH_CAP = 9.0V
-100
–
100
VBUSIN = 4.5V, VH_CAP = 9.0V when device is not signalling
-100
BUSIN to H_CAP Rectifier Voltage Drop
VRECT
IHCAP = 15mA
IHCAP = 100mA
Unit
V
(4)
H_CAP Diode Efficiency
%
IHCAP = 400mA, BUSIN = 25V
BUSIN Bias Current
μA
IBIAS
Rectifier Leakage Current
100
IRLKG
-20
–
20
μA
VRO
4.9
5.0
5.1
V
VRLINE
–
–
20
mV
VRLD
–
–
15
mV
–
–
(25)
mV
–
–
(50)
mV
25
35
45
mA
–
3.0
6.0
–
3.0
6.0
VBUSIN = 0V, VH_CAP = 25V
REGOUT
5.8V < VH_CAP ≤ 25V, 0 ≤ IRO ≤ 14mA
REGOUT Line Regulation
IRO = 14mA, 6.0V ≤ VH CAP ≤ 25V
IRO is the total internal and external load current
REGOUT Load Regulation
0 ≤ IRO ≤ 14mA, 6.0V ≤ VH CAP ≤ 25V,
REGOUT Transient Line Regulation(5)
IRO = 14mA, 0 V ≤ VBUSIN ≤ 30 V, 8V/us @ BUSIN, or, 5V/us @
HCAP
CRO = 2.2 uF, CRO ESR = 0.063-2.2Ω @ 20kHz,
0.004-0.072Ω @ 200kHz
REGOUT Transient Load Regulation(5)
0 ≤ IRO ≤ 14mA, 6.0V ≤ VH CAP ≤ 25V, 2mA/us @ IRO,
CRO = 2.2uF, CRO ESR = 0.063-2.2Ω @ 20kHz,
0.004-0.072Ω @ 200kHz
REGOUT Current Limit, VREGOUT = 0V
Hi-side Bus Switch Resistance
ILMT
Low-side Bus Switch Resistance
ISWL = 160mA (Bus Switch Active)
Ω
RSWH
0 ≤ VBUSIN ≤ 30V, ISWH = 160mA (Bus Switch Active)
Ω
RSWL
Notes
4. EFF = 400mA/IBUSIN - IQ
5.
Assured by design.
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Freescale Semiconductor
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ELECTRICAL CHARACTERISTICS
STATIC ELECTRICAL CHARACTERISTICS
Table 3. Static Electrical Characteristics (continued)
Characteristics noted under conditions -0.3V ≤ VBUSIN ≤ 30V, 6.0V ≤ VH_CAP ≤ 30V, - 40°C ≤ TA ≤ 125°C,
RTNIN=AGND = 0V, unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25°C under
nominal conditions, unless otherwise noted.
Characteristic
Bus Switch Resistance Matching
Symbol
Min
Typ
Max
–
–
0.3
Ω
RDSW
= | RSWH - RSWL |, TA = 25°C
= | RSWH - RSWL |, TA = 125°C
I/O0, I/O1, I / O2, and TEST Pull-down Current
Unit
0.6
μA
IPD
VIN = 1.0V
5.0
–
20
ILK
-10
–
10
μA
IPDANn
5.0
–
20
μA
IANnLKG
-1.0
–
1.0
μA
Signal
VTHS
2.8
3.0
3.2
Frame
VTHF
5.5
6.0
6.5
I/O0, I/O1, I/O2, and TEST Leakage Current
I/On, TEST = 0V
AN0, AN1 Pull-down Current (Enabled mode)
VIN = 1.0V(6)
AN0, AN1 Leakage Current (Disabled mode)(6)
BUSIN Logic Thresholds
V
BUSIN Hysteresis
mV
Signal
VHYSS
60
–
120
Frame
VHYSF
100
–
300
VBUSIN = 4.0V
9.9
11
12.1
VBUSIN = 1.175V
7.0
–
–
-20
–
20
BUSIN Response Current
BUSIN, BUSOUT Leakage Current
IRSP
IBUSINLK
mA
μA
High Side Bus Switch Open
BUSIN = 25V, BUSOUT = 0V
BUSIN= 0V, BUSOUT = 16V
RTNIN, RTNOUT Leakage Current
μA
IBUSRTNLK
Low Side Bus Switch Open
RTNIN = 14V, RTNOUT = 0V
-20
–
20
RTNIN = 0V, RTNOUT = 16V
-125
–
125
ICROSSLK
-20
–
20
μA
ADCRES
10
10
10
bit
CADC
–
–
20
pF
ZIN
–
–
5.0
kΩ
ADCINL
-3.5
–
+3.5
LSB
ADCFS
-3.5
–
+3.5
LSB
RTNIN to BUSOUT Leakage Current
High Side Bus Switch Open
RTNIN = 14, BUSOUT 0V
ADC Resolution
ANn Input Capacitance(7)
Input Source Impedance(7)
ADC Code Conversion Error (INL)
Source Resistance < 1.0kΩ
Full Scale Error
6.
7.
In the default, AN0 pull-down current is disabled and AN1 pull-down current is enabled. AN1 pull-down current is disabled during AN1
A2D conversion. At the same time, AN0 pull-down current is enabled.
Assured by design.
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ELECTRICAL CHARACTERISTICS
STATIC ELECTRICAL CHARACTERISTICS
Table 3. Static Electrical Characteristics (continued)
Characteristics noted under conditions -0.3V ≤ VBUSIN ≤ 30V, 6.0V ≤ VH_CAP ≤ 30V, - 40°C ≤ TA ≤ 125°C,
RTNIN=AGND = 0V, unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25°C under
nominal conditions, unless otherwise noted.
Characteristic
Symbol
Min
Typ
Max
Unit
ADCABS
-4.0
–
+4.0
LSB
ADCDNL
–
–
2.0
LSB
Input High Voltage
VIH
70%*VREG
–
–
Input Low Voltage
VIL
–
–
30%*VREG
VHYS
300
Output Low (IL = 1.0mA)
VOL
0
–
0.8
Output High (IL = -500μA)
VOH
VREGOUT 0.8
–
VREGOUT
Voltage at HCAP
VPORHCAP
6.0
6.39
6.77
Voltage at REGOUT
VPORREG
4.25
4.5
4.75
Absolute Error(8)
0.5V < Input Voltage < 4.5V
ADC Code Conversion Error (DNL)
Source Resistance < 1.0 kΩ
I / O Input Levels
I/O Input Hysteresis(8)
V
mV
I / O Logic Output Levels
V
POR Detect Thresholds
V
Notes
8. Assured by design.
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Freescale Semiconductor
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ELECTRICAL CHARACTERISTICS
DYNAMIC ELECTRICAL CHARACTERISTICS
DYNAMIC ELECTRICAL CHARACTERISTICS
Table 4. Dynamic Electrical Characteristics
Characteristics noted under conditions -0.3V ≤ VBUSIN or VBUSOUT ≤ 30V, 6.0V ≤ VH_CAP ≤ 30V, - 40°C ≤ TA ≤ 125°C,
AGND = 0V, unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25°C under nominal
conditions, unless otherwise noted.
Characteristic
Symbol
Min
Typ
Max
Unit
Internal Oscillator Frequency
fOSC
9.0
10.0
11.0
MHz
Internal Oscillator Duty Cycle
DCOSC
45
50
55
%
tBS
–
–
50
μs
DRATE
100
–
200
kbps
tTO
2.0
–
4.0
ms
tADC
–
–
20
μs
1.0mA to 9.0mA Transition Rise
t ITR_R
–
–
8.0
9.0mA to 1.0mA Transition Fall
t ITR_F
–
–
8.0
Initialization to Bus Switches Close
Communication Data Rate
Loss of Signal Reset Time
(9)
Maximum Time for BUSIN to Be Below Frame Threshold
ADC Code Conversion Time(10)
BUSIN Response Current Slew Rate
mA /μs
BUSIN Timing to Response Current
μs
BUSIN Negative Voltage Transition = 3.0V to IRSP = 7.0mA Rise
tRSP_R
TA = -40°C
–
–
2.5
TA = +25°C
–
–
2.5
TA =+125°C
–
–
3.0
BUSIN Negative Voltage Transition = 3.0V to IRSP = 5.0mA Fall
–
–
2.5
tRSP_F
Bus Signal Duty Cycle(9)
%
Logic [0] (~ 1/3 + 20%)
DCL
25
33
40
Logic [1] (~ 2/3 + 20%)
DCH
54
67
80
tTRIO
–
–
100
ns
tINDLYIO
–
–
300
ns
tOUTDLYIO
–
11.5
15
μs
tADCDIS
–
–
300
ns
ON (rising edge)
tPORMASKHCAP
2.0
5.0
9.0
OFF (falling edge)
tPORMASKHCAP
1.0
3.5
8.0
I/O Transition Time (CLoad =
50pF)(9)
I/O Delay from Input State Change to Status Register Valid
(9)
I/O Delay from DBUS Command to I/O Output State Change
Delay from I/O1 Rising Edge to ADC Value = 3F8
(9)
HCAP tPOR Mask
μs
(ON)
(OFF)
REGOUT tPOR Mask
ON (rising edge)
μs
tPORMASKREG
2.0
5.0
9.0
1.0
3.5
8.0
OUT(ON)
OFF (falling edge)
tPORMASKREG
OUT(OFF)
Notes
9. Assured by design.
10. Assured by design. Conversion is started and completed during idle time.
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ELECTRICAL CHARACTERISTICS
TIMING DIAGRAMS
TIMING DIAGRAMS
End of Initialization
Command
Frame
Threshold
BUSIN
Frame
Threshold
tTO
tBS
Closed
BUS Switches
Open
Internal Reset
Reset
Figure 4. Bus Switch and Reset Timing
9.0mA
9.0mA
7.0mA
7.0mA
RESPONSE
CURRENT
1.0mA
1.0mA
tITR_R
tITR_F
tRSP_F
tRSP_R
BUSIN
3.0V
3.0V
Figure 5. Response Current Timing
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9
FUNCTIONAL DESCRIPTION
INTRODUCTION
FUNCTIONAL DESCRIPTION
INTRODUCTION
The 33784 is designed to be used with a sensor at a
location remote from a centralized MCU. This device
provides power, measurement, and communications
between the remote sensor and the centralized MCU over a
DSI 2.02 compliant bus. Sensors such as accelerometers
can be powered from the regulated output of the device, and
the resulting analog value from the sensor can be converted
from an analog level to a digital value for transmission over
the bus, in response to a query from the MCU. There are two
analog inputs to a 10-bit analog-to-digital converter (ADC).
Three I/O lines can be configured by the central MCU over
the bus as digital inputs or digital outputs.
Power is passed from BUSIN through on-chip rectifiers to
an external storage capacitor. The capacitor stores energy
during the highest voltage excursions of the BUSIN pin (idle)
and supplies energy to power the device during low
excursions of BUSIN.
An under-voltage circuit provides a reset signal during lowvoltage conditions and during power-up/power-down.
Data from the Central Control Unit (CCU) is applied to the
BUSIN pin as voltage levels that are sensed by level
detection circuitry. A serial decoder detects these transitions
and decodes the incoming data. Responses are passed
through a serial encoder and are transmitted via a switched
current source that is slew-rate controlled.
FUNCTIONAL PIN DESCRIPTION
ANALOG GROUND (AGND)
HOLDING CAPACITOR (H_CAP)
This pin is the low reference level and power return for the
analog-to-digital converter (ADC). It is internally connected to
RTNIN
A capacitor attached to this pin is charged by the bus
during bus idle and supplies current to run the device and for
external devices via the REGOUT pin during non-idle
periods.
TEST OUTPUT (TOUT)
This output is low for normal operation and will go high
when the device is placed into a test mode. See Test Mode
on page 14.
DBUS INPUT (BUSIN)
IDDQ (IDDQ)
BUS RETURN IN (RTNIN)
This input is used for measuring the quiescent current of
the device during IC manufacturing test. This pin should be
open in the application.
This pin connects to the low side of the differential bus and
provides the common return for power and signalling. It is
internally connected to AGND.
ANALOG INPUT (AN0, AN1)
DBUS OUTPUT (BUSOUT)
Inputs to the analog-to-digital converter.
LOGIC I/O (I/O0, I/O1, I/O2)
These pins provide a logic level outputs or inputs.
TEST MODE ENABLE (TEST)
This pin attaches to the high side of the differential bus and
responds to initialization commands.
This pin is the switched BUSIN signal and is connected to
the BUSIN pin of the next device in the daisy chain.
BUS RETURN OUT (RTNOUT)
This pin is the switched RTNIN signal and is connected to
the RTNIN pin of the next device in the daisy chain.
A high input places this device into special test mode. See
Test Mode on page 14.
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FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
MC33784 - Functional Diagram
Supply Voltage
Rectifier
5.0V Regulator
Under-voltage Detector
Sensing & Control
Receiver
Bus Switches
Control Logic
Clock
Analog to Digital Converter
Power Stage
Transmitter
Supply Voltage
Sensing & Control
Power Stage
Bus switches
Functional Internal Block Diagram
SUPPLY VOLTAGE
RECTIFIER
There is an on-chip rectifier, which allows power and
communications to be delivered to the 33784 over the bus.
The rectifier lies between BUSIN and H_CAP. During the idle
state of the bus, the rectifier allows the bus to charge an
external storage capacitor attached to H_CAP. During
signaling, the rectifier isolates H_CAP from the bus to prevent
the bus from draining the external capacitor while signaling.
The capacitor then supplies power to the 33784 during
signaling. The signaling time and the size of the external
capacitor must be selected so that the voltage on HCAP does
not drop below 6.77V during signaling.
5.0V REGULATOR
An on-chip 5V regulator supplies internal power for the
33784 and also supplies power to external devices, such as
accelerometers via the REGOUT pin. A bypass capacitor is
required on the REGOUT pin to keep the regulator stable. All
current supplied by the regulator is derived from the external
capacitor attached to H_CAP.
UNDER-VOLTAGE DETECTOR
The under-voltage detector issues a power-ON reset
(POR) signal during power-up and power-down of the 33784.
It also monitors the voltage on HCAP and REGOUT and
issues a reset when either of these pins fall below their
respective POR thresholds. The reset signal is filtered to
prevent glitches on HCAP or REGOUT from causing an
erroneous reset. Any time the 33784 is reset, the device will
need to be re-initialized before it will respond to further
commands.
LOGIC AND CONTROL
RECEIVER
The receiver detects the voltage on BUSIN and senses
when the bus is idle and when it is signaling. Communication
on the bus always begins when the voltage on BUSIN drops
below the frame threshold. This change from idle mode to
signal mode is sensed by the receiver and is interpreted as
the start of an incoming word.
The first bit in the word begins when the bus voltage drops
below the Signal threshold. This starts a counter in a serial
decoder, which essentially measures the amount of time that
the bus voltage is below the signal threshold. When the bus
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Analog Integrated Circuit Device Data
Freescale Semiconductor
11
FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
voltage rises above the signal threshold, the counter
measures the time the bus is above the signal threshold.
When the bus voltage falls below the signal threshold again,
the first bit is finished and the next bit begins. The process is
repeated for each bit in the command.
The decoder interprets the bit as a logic [0] if the bus spent
more time below the signal threshold than above it.
Conversely, the decoder interprets the bit as a logic [1] if the
bus spent more time above the signal threshold than below it.
The advantage to this method of communication is that it will
accept data over a wide range of data rates and it is not
dependent on an accurate clock. A logic [0] is typically
indicated by spending 2/3 of the total bit time low, and a
logic [1] is typically indicated by spending 2/3 of the total bit
time high.
The command ends when the bus voltage rises above the
frame threshold and returns to the idle state.
Each threshold comparator has hysteresis to help to filter
noise on the bus during the transitions. There is also a filter,
which issues a reset if the bus remains below the frame
threshold for longer than the timeout limit. This allows the
33784 to reset itself if the connection to the Master IC is lost,
or if power is removed from the system, or if a short-to-analog
ground condition exists on one of the bus pins and the bus
switch is closed.
CONTROL LOGIC
The control logic performs the digital operations carried
out by this device. Its principle functions include:
• Decoding input instructions
• Controlling the general purpose I /O in response to
BUSIN commands
• Controlling A / D conversions
• Forming response words
• Capturing and storing addresses
• Controlling the bus switch (BS)
• Resetting the device on power-up
• Reading the general purpose I /O logic values and
responding to requests for these values
• Generating a cycle redundancy check (CRC) for the
received data and transmitted data in conformance with
the DBUS standard
Additionally, the control logic performs error checking on
the received data. If errors are found, no action is taken and
no response is made. Errors include:
• CRC received doesn’t match CRC of received data
• Number of received bits doesn’t match required bit
count
See Figure 6 for the Control Logic Block Diagram
CLOCK
An internal 10 MHz oscillator provides the clock for all logic
and timing functions in the IC. The signaling system and all
internal operations are such that no external precision timing
device is needed in the normal operation of the 33784.
An LFSR-based PRBS is clocked by the oscillator and
generates a random bitstream that dithers the oscillator via a
switch. Dither on the clock creates a spread spectrum for
noise improvement.
ANALOG-TO-DIGITAL CONVERTER
The ADC has 10-bit resolution. It uses REGOUT as a fullscale reference voltage and AGND for a zero-level reference.
The ADC uses the on-chip oscillator for sequencing.
The analog voltage on AN0 or AN1 is converted to a digital
value in response to the Request AN0 or Request AN1
commands on the bus. Only the Request ANn commands will
trigger a new conversion. The requested bits will be
transmitted during the next command sent on the bus.
To prevent inaccurate reporting near analog ground and
the supply rail, the ADC will only report digital values between
hex 0020 and 03E3. Any analog voltage that would result in
a digital value below 0020 will be reported as 0020. Likewise,
any voltage that would result in a value above 03E3 will be
reported as 03E3. The only time the ADC will report a value
outside the range of hex 0020 : 03E3 is when an error occurs
during the analog conversion inside the IC. In this case, the
error code 03F8 will be reported. This is summarized in
Table 5, page 14.
The ADC is also designed to report an error depending on
the state of I/O1. If I/O1 is configured as an input and is set
high when the conversion takes place, then the ADC will
always report the error code 03F8. If I/O1 is low when the
conversion takes place, then the ADC will report the
converted digital value as described above. If I/O1 is
configured as an output, then the state of I/O1 is irrelevant
and the ADC will always report the converted digital value, as
described above.
POWER STAGE
TRANSMITTER
At the same moment the receiver detects incoming
commands by sensing the voltage on the bus, the transmitter
replies by changing the current flowing in the bus. Each time
the bus voltage falls below the signal threshold to start a new
incoming bit, the transmitter switches a fixed current source
on or off. A logic [1] is indicated if the current source is
switched on during the bit time. A logic [0] is indicated if the
current source is switched off during the bit time.
The current source is always switched off while the bus is
idle.
As the response current is switched on and off, the
transitions are slew-rate limited to reduce EMI. Without the
slew control, the fast transitions could generate higher
frequency harmonics, that could interfere with receivers
tuned to frequencies well above the data rate of this device.
33784
12
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
BUS SWITCHES
A high side bus switch lies between BUSIN and BUSOUT
and a low side bus switch lies between RTNIN and RTNOUT.
These switches can be opened or closed via commands on
the bus. The bus switch facilitates the daisy chain operation
of the 33784. When the switch is open, BUSIN is isolated
from BUSOUT, RTNIN is isolated from RTNOUT, and any
communication that is seen on one pin will not be transmitted
to the other. In this way, the CCU can initialize the first 33784
or any other slave device in the daisy chain and program an
address into it.
Once the first device in the daisy chain is initialized, the
bus switches can be closed, effectively shorting BUSIN to
BUSOUT, and RTNIN to RTNOUT. Now all communication
that is seen on one pin will be passed to the other. The Master
IC can send a command through the initialized device to the
next un-initialized device in the daisy chain. The process is
repeated until every device in the daisy chain has been
initialized with a unique address.
Once a device’ bus switches are closed they remain
closed except for the following conditions:
- reception of a CLEAR command
- bus lines remain below the frame threshold for longer
than the bus timeout period in which case the device will reset
and the bus switches will open.
- HCAP or VREG decay below the POR threshold for a time
exceeding the POR Mask time in which case the device will
reset and the bus switches will open.
Once the bus switches open they can only be closed again
with an initialization command.
33784
Analog Integrated Circuit Device Data
Freescale Semiconductor
13
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
INPUT / OUTPUT PINS
Table 6. 8-Bit ADC Value Mapping
There are three I/O pins on the 33784 that can serve as
either logic inputs or logic outputs. At power-up or after a
Clear Command, the pins default to inputs. They can be
individually configured as outputs as needed via the I/O
Control Command on the bus.
Hex
Table 5. 10-Bit ADC Value Mapping
Hex
Description
03FF
Prohibited
•
•
•
•
•
•
03F9
Prohibited
03F8
Error Code
03F7
Prohibited
•
•
•
•
•
•
03E4
Prohibited
03E3
G Range
•
•
•
•
•
•
0020
G Range
001F
Prohibited
•
•
•
•
•
•
0000
Prohibited
Table 6. 8-Bit ADC Value Mapping
Hex
Description
FF
Prohibited
FE
Error Code
FD
Prohibited
•
•
•
•
•
•
Description
FA
Prohibited
F9
Prohibited
F8
G Range
•
•
•
•
•
•
08
G Range
07
Prohibited
•
•
•
•
•
•
02
Prohibited
01
Prohibited
00
Prohibited
ADDRESSING
The 33784 may be connected in a daisy chain to other
DBUS devices. If this device is connected in a daisy chain,
then it will receive its 4-bit address during initialization on the
bus.
TEST MODE
The 33784 can be configured in a special test mode for
evaluation purposes. The test mode can only be entered if all
of the following conditions are true:
• The TEST1 pin is at a logic high level
• The correct test mode command is sent to the device on
the bus
• One of the internal test mode registers is accessed
Accessing the test mode registers and writing different
values to them can change the behavior of many of the pins
on the device, including the TOUT pin, which is only active in
test mode. The test mode can be intermixed with other bus
commands to evaluate the behavior of internal circuit blocks.
To prevent accidental activation of the test mode, the
TEST1 pin should be tied externally to AGND. The TOUT pin
should be grounded when not in TEST mode.
33784
14
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
Received Message
From MASTER
Data
10MHz Clock
Bus Controller
Command Buffer
Data Clock
Frame_OK
CRC
Check
DBUS Registers
Latch
INIT
REQ STATUS
REQ AN0
I/O CONTROL
REQ ID
REQ AN1
CLEAR
FORMAT CONTROL
TEST
DATA OUT [2:0]
I/O [2:0]
AD_SEL
AD_DATA [9:0]
TEST
Load Enable
Data Clock
Response Shifter
10MHz Clock
CRC Generator
I Response ON
SEL
Figure 6. DBUS Slave Logic Block Diagram
COMMUNICATION FORMAT
DBUS messages are composed of individual words
separated by a frame delay. Transfers are full duplex.
Command messages from the master occur at the same time
as responses from the slaves. Slave responses to commands
occur during the next command message. This allows slaves
time to decode the command, retrieve the information, and
prepare to send it to the master. A bus traffic example is
shown in Figure 7.
The example shows three commands separated by the
minimum frame delay followed by a command after a longer
delay.
Figure 7. Bus Traffic Example
33784
Analog Integrated Circuit Device Data
Freescale Semiconductor
15
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
In case there is a bus error (due to induced noise or a bus
fault), both the master and slave devices will likely read bad
data. The slave reacts to bad data by not sending a response
during the next frame, and clears the any pending response.
The master will detect a CRC error (if enabled) once it
receives the corrupted data sent by the slave, and once again
when the slave fails to respond. This is illustrated in Figure 8.
CRC
Error
Bus Error
Master
Slave
Command N
Response N-1
When this error occurs, the system software needs to
acknowledge this condition and resend a command of the
same size so that it can receive the proper response.
Failure to take corrective action will result in unintended
errors as shown in Figure 8. In this case, the master will miss
Responses N and N+1.
CRC
Error
Command N+1
Command N+2
Command N+3
Command N+4
Response N
No Response
Response N+2
Response N+3
CRC
Error
Figure 8. Bus Traffic With Receive Error and Recovery
STANDARD DBUS COMMAND STRUCTURE
ENHANCED DBUS COMMAND STRUCTURE
Two word sizes are available for standard DBUS
commands. These are termed “long word” and “short word”.
A standard long word always consists of 8 data bits,
4 address bits, 4 command bits, and 4 cyclic redundancy
check (CRC) bits. The data bits are always sent first, starting
with the MSB, and are followed by the address bits, then the
command bits, and ending with the CRC bits. Refer to
Table 7, page 17.
A standard short word consists of 4 address bits,
4 command bits, and 4 CRC bits. The address bits are
always sent first, starting with the MSB, followed by the
command bits, and ending with the CRC bits. This is also
shown in Table 7.
Some commands can be sent in either standard long word
or standard short word format as desired. If these commands
are sent in long word format, the data bits are “don’t-care” for
the 33784, but should all be set to 0 to maintain future
compatibility.
When a standard long word or short word is sent on the
bus, the 33784 will calculate a CRC as each bit is received.
The CRC is calculated using the polynomial X4+1 and seed
1010. The polynomial and seed cannot be changed when
communicating in standard mode. At the conclusion of the
transmission, the 33784 will compare the calculated CRC
with the CRC included within the message. If the two match,
the message is considered valid and the 33784 will act on the
message accordingly. If the calculated CRC does not match
the CRC included within the message, the 33784 will ignore
the transmission and the message will be discarded.
In addition to standard DBUS commands, the 33784 can
accept enhanced DBUS commands. Like standard
commands, there are two word sizes available for enhanced
commands. These, like the standard long word, are termed
“enhanced long word” and “enhanced short word”. An
enhanced long word always consists of 8 data bits, 4 address
bits, 4 command bits, and 4 CRC bits. The data bits are
always sent first, starting with the MSB, and are followed by
the address bits, then the command bits, and ending with the
CRC bits. Refer to Table 7.
However, an enhanced long word differs from a standard
long word in that the CRC polynomial and seed are not fixed
and can be programmed into the IC via the bus. The method
of programming the polynomial and seed is discussed in
Format Control Command and Response, page 23.
Likewise, enhanced short words will also use the
polynomial and seed that have been programmed into the IC.
Enhanced short words consist of 0 or 2 data bits, 4 address
bits, 4 command bits, and 4 CRC bits. The data bits (if any)
are sent first, followed by the address bits, followed by the
command bits, and ending with the CRC bits. This is shown
in Table 7. The optional data bits are only place holders and
are used so that longer responses can be transmitted. If the
optional data bits are used, they are “don’t-care” for the
33784, but should both be set to 0 to maintain future
compatibility.
Some commands can be sent in either enhanced long
word or enhanced short word format as desired. If these
commands are sent in enhanced long word format, the data
bits are “don’t-care” for the 33784, but should all be set to 0
to maintain future compatibility.
33784
16
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
When an enhanced long word or short word is sent on the
bus, the 33784 will calculate a CRC as each bit is received.
The CRC is calculated using the polynomial and seed that
have been programmed into the IC via the bus. At the
conclusion of the transmission, the 33784 will compare the
calculated CRC with the CRC included within the message. If
the two match, the message is considered valid and the
33784 will act on the message accordingly. If the calculated
CRC does not match the CRC included within the message,
the 33784 will ignore the transmission and the message will
be discarded.
Table 7. Standard and Enhanced DBUS Command Structure
Word Type
Symbol First
Data
Address
Command
CRC
Last
Standard Long Word
LW
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
C3
C2
C1
C0
X3
X2
X1
X0
Enhanced Long Word
ELW
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
C3
C2
C1
C0
X3
X2
X1
X0
Standard Short Word
SW
A3
A2
A1
A0
C3
C2
C1
C0
X3
X2
X1
X0
8-Bit Enhanced Short Word
8-Bit ESW
A3
A2
A1
A0
C3
C2
C1
C0
X3
X2
X1
X0
A3
A2
A1
A0
C3
C2
C1
C0
X3
X2
X1
X0
D1
10-Bit Enhanced Short Word 10-Bit ESW
D0
Table 8. Standard and Enhanced DBUS Response Structure
Word Type
Symbol
Response
Standard Long Word
LW
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
X3
X2
X1
X0
Enhanced Long Word
ELW
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
X3
X2
X1
X0
Standard Short Word
SW
D7
D6
D5
D4
D3
D2
D1
D0
X3
X2
X1
X0
8-Bit Enhanced Short Word
8-Bit ESW
D7
D6
D5
D4
D3
D2
D1
D0
X3
X2
X1
X0
D7
D6
D5
D4
D3
D2
D1
D0
X3
X2
X1
X0
First
10-Bit Enhanced Short Word 10-Bit ESW
D9
D8
CRC
Last
STANDARD DBUS RESPONSE STRUCTURE
ENHANCED DBUS RESPONSE STRUCTURE
There are two standard response lengths to correspond
with the two standard command word lengths. A standard
long response always consists of 16 data bits and 4 CRC bits.
A standard short response always consists of 8 data bits and
4 CRC bits. Refer to Table 8.
In both cases, the data bits are sent first, starting with the
MSB, and are followed by the CRC bits. The CRC bits are
calculated from the data bits using the standard polynomial
X4+1 and seed 1010. The polynomial and seed cannot be
changed when responding in standard mode.
Normally, standard long responses will be sent for
standard long commands, and standard short responses will
be sent for standard short commands. However, if a long
command is followed by a short command, then the response
to the long command will occur during the short command
and will be truncated. In this case, the response to the long
command is considered invalid.
Similarly, if a short command is followed by a long
command, then the response to the short command will occur
during the long command and will contain extra bits. In this
case the response to the short command is considered
invalid.
There are two enhanced response lengths to correspond
with the two enhanced command word lengths. Like the
standard long word, an enhanced long response always
consists of 16 data bits and 4 CRC bits. The data bits are sent
first, starting with the MSB, and are followed by the CRC bits.
The CRC bits are calculated from the data bits using the
polynomial and seed that was programmed into the IC via the
bus.
An enhanced short response consists of either 8 or 10
data bits and 4 CRC bits. The enhanced short response will
have 8 data bits if the enhanced short command did not use
the optional 2 bits, and it will have 10 data bits if the enhanced
short command did use the optional 2 bits.
In certain cases, the optional 2 bits might be used in the
command, but due to the nature of the command, the
response only contains 8 bits of data. In this circumstance,
the response will be right-padded with zeros so that 10 data
bits are sent, followed by the CRC.
In other cases, the optional 2 bits might not be used in the
command, but due to the nature of the command, the
response contains 10 bits of data. In this circumstance, the 2
least significant bits of the response data will be dropped and
only the 8 most significant data bits are sent, followed by the
CRC. This is illustrated in logic Commands and Registers,
page 18.
33784
Analog Integrated Circuit Device Data
Freescale Semiconductor
17
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
Normally enhanced long responses will be sent for
enhanced long commands, and enhanced short responses
will be sent for enhanced short commands of the same
length. If an enhanced long word is sent after an enhanced
short word, or an enhanced short word is sent after an
enhanced long word, or two enhanced short words of
different lengths are sent in succession, then the first
response will have a different length than the second
command, and therefore the first response will be invalid.
LOGIC COMMANDS AND REGISTERS
INTRODUCTION
The following sections describe in detail each of the
commands that can be sent to the 33784. All of these
commands can be sent in long-word format (standard or
enhanced). Some of the commands can be sent in shortword format (standard or enhanced), but not all. Refer to the
table in each section for the available formats for each
command. The responses for each command can also be
found in the tables. The 4-bit CRC, which is appended to
every command and every response, has been omitted.
Many commands have “don't-care” bits, which can be set
to 0 or 1 without affecting the command. Although the 33784
will respond the same in either case, it is recommended that
all “don't-care” bits be set to 0 to maintain future compatibility.
INITIALIZATION COMMAND AND RESPONSE
(BUSIN INPUT ONLY)
Following power-up or after a POR has occurred, the
Initialization Command must be sent to the 33784 before it
Data
–
BSH BSL
OD
will respond to other commands. The command format is
found in Figure 9.
The Initialization Command may be used to initialize a
daisy chain device. The Initialization Command is sent to
address zero. The command will be received by the next
daisy chain device with its bus switch open. Reception of this
command will assign the device address and close the bus
switch if the BSH and BSL bits are logic [1]
Once a device has received an Initialization Command, it
will ignore further initialization commands unless it has
received a clear command or undergone a power-ON reset.
The response is sent during the next message following a
valid Initialization Command to the addressed device. The
response is shown in Figure 9. Because this is a long-word
only command, there is no short word response. The BSH
and BSL bits returned are the same as the bits sent in the
command. The Request Status command can be used to find
the logic commanded state of the bus switches.
Address
PA3 PA2 PA1 PA0
A3
A2
Command
A1
A0
0
0
0
Word Type
0
Not Valid
LW
SW & ESW (8-bit)
Not Valid
ESW (10-bit)
Response
A3
A2
A1
A0
0
0
0
0
0
Word Type
BSH BSL
0
PA3 PA2 PA1 PA0
No Response
LW
SW & ESW (8-bit)
No Response
ESW (10-bit)
Legend
A [3:0] = Address bits. The slave address.
PA [3:0] = Bus address to set the device to.
An address value of 0000 is ignored by all devices (no
initialization, no bus switch closure, and no response)
An address value of 0000 is ignored by all devices (no
initialization, no bus switch closure, and no response)
BSH = High Side Bus Switch Position (1 = closed).
OD = Oscillator dither:
BSL = Low Side Bus Switch Position (1 = closed).
0 = no dither (default)
“–” = Don’t care bit. Can be 0 or 1.
1 = dither
Figure 9. Initialization Command Response Format
REQUEST STATUS COMMAND AND RESPONSE
This command causes the addressed device to return the
status of the BSH and BSL bits and the logic levels of the I /
O. The command format is found in Figure 10.
The 33784 will only act on this command if the address bits
in the command match the address that the device was
initialized with. If the addresses do not match, the device will
do nothing and no response will be generated.
33784
18
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
The response is sent during the next message following a
valid Request Status command to the addressed device.
Because this is a long-word only command, there is no shortword response.
Data
–
–
–
–
The I/O bits reflect the logic states of the I/O pins. These
states are latched into an internal register after the Request
Status command is received (approximately TBD μs after the
bus rises above the frame threshold), and are held until the
response is transmitted. Any activity that occurs on the I/O
pins after the states are latched will be ignored.
Address
–
–
–
–
A3
A2
A1
Command
A0
0
0
0
Word Type
1
Not Valid
SW & ESW (8-bit)
Not Valid
ESW (10-bit)
Response
A3
A2
A1
A0
0
0
0
0
0
LW & ELW
Word Type
BSH BSL
0
0
IO2
IO1
IO0
No Response
No Response
LW & ELW
SW & ESW (8-bit)
ESW (10-bit)
Legend
A [3:0] = Address bits. The address of the selected device.
An address value of 0000 is ignored by all devices.
“–” = Don’t care bit. Can be 0 or 1.
IO [2:0] = Values at logic I /Os.
BSH = High Side Bus switch position (1 = closed).
BSL = Low Side Bus switch position (1 = closed).
Figure 10. Request Status Command and Response Format
REQUEST AN0 COMMAND AND RESPONSE
This command causes the analog voltage on the AN0 pin
to be measured and converted by the on-chip 10-bit ADC.
The approximate timing for the conversion following this
command is shown in Figure 11. The response to this
command depends on the format in which the command was
sent. The sensor data is sent in the format shown in Table 10.
The 33784 will only act on this command if the address bits
in the command match the address that the device was
initialized with. If the addresses do not match, the device will
do nothing and no response will be generated.
33784
Analog Integrated Circuit Device Data
Freescale Semiconductor
19
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
End of
Request ANx
Command
Frame
Threshold
BUSIN
All values are approximate and
are not production tested.
13.6μs
Enabled
ADC
Enable
4.6μs
Disabled
1.6μs
Sampling
ADC
Sampling
7.4μs
Not Sampling
4.4μs
0.1μs
ADC
Conversion
Completed
Conversion
Complete
Figure 11. Approximate ADC Conversion Timing
Data
–
–
–
–
Address
–
–
–
–
–
–
Command
Word Type
A3
A2
A1
A0
0
0
1
0
LW & ELW
A3
A2
A1
A0
0
0
1
0
SW & ESW (8-bit)
A3
A2
A1
A0
0
0
1
0
ESW (10-bit)
Response
A3
A2
A1
A0
0
0
0
B9
0
B8
Word Type
B9
B8
B7
B6
B5
B4
B3
B2
LW & ELW
B9
B8
B7
B6
B5
B4
B3
B2
SW & ESW (8-bit)
B7
B6
B5
B4
B3
B2
B1
B0
ESW (10-bit)
Legend
A [3:0] = Address bits. The address of the selected device.
B [9:0] = Measured value.
An address value of 0000 is ignored by all devices.
“–” = Don’t care bit. Can be 0 or 1.
Figure 12. Request AN0 Command and Response Format
REQUEST AN1 COMMAND AND RESPONSE
This command causes the analog voltage on the AN1 pin
to be measured and converted by the on-chip 10-bit ADC.
The approximate timing for the conversion following this
command is shown in Figure 11, page 20. The response to
this command depends on the format in which the command
was sent. The sensor data is sent in the format shown in
Figure 12.
The 33784 will only act on this command if the address bits
in the command match the address that the device was
initialized with. If the addresses do not match, the device will
do nothing and no response will be generated.
33784
20
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
Data
–
–
–
–
Address
–
–
–
–
–
–
Command
Word Type
A3
A2
A1
A0
0
1
0
1
LW & ELW
A3
A2
A1
A0
0
1
0
1
SW & ESW (8-bit)
A3
A2
A1
A0
0
1
0
1
ESW (10-bit)
Response
A3
A2
A1
A0
0
0
0
B9
0
B8
Word Type
B9
B8
B7
B6
B5
B4
B3
B2
LW & ELW
B9
B8
B7
B6
B5
B4
B3
B2
SW & ESW (8-bit)
B7
B6
B5
B4
B3
B2
B1
B0
ESW (10-bit)
Legend
A [3:0] = Address bits. The address of the selected device.
B [9:0] = Measured value.
An address value of 0000 is ignored by all devices.
“–” = Don’t care bit. Can be 0 or 1.
Figure 13. Request AN1 Command and Response Format
I / O CONTROL COMMAND AND RESPONSE
This command can be used to configure the direction of
the I/O pins, and force their states if configured as outputs.
Refer to Figure 14 for the command and response format.
The response is sent during the next message following a
valid I/O Control command to the addressed device. Because
this is a long-word only command, there is no short word
response.
The direction (DR) bits are used to specify the direction
(input or output) of each pin independently. If the DR bit for a
specific I/O pin is set to 1, then that I/O pin will be an output
and the state of the level (Lx) bit will determine whether the
pin is driven high or low. If the DR bit for a specific I/O pin is
set to 0, then that pin will be an input and the Lx bit in the
command will have no affect on the state of the pin.
In the response to the I/O Control Command, the DR bits
will show the direction that the pins were programmed. The
Lx bits will have the values that were set in the command.
These values may not reflect the actual states of the pins. To
obtain the accurate states of the pins, the Request Status
Command should be used.
The 33784 will only act on the I/O Control Command if the
address bits in the command match with the address that the
device was initialized. If the addresses do not match, the
device will do nothing and no response will be generated.
Address ‘0000’ is a global command. All slaves in the
signal path will configure their I/O pins according to the state
of the data bits. No response results from the I/O control
global command.
33784
Analog Integrated Circuit Device Data
Freescale Semiconductor
21
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
Data
–
L2
L1
L0
Address
–
DR2
DR1
DR0
A3
A2
A1
Command
A0
0
0
1
Word Type
1
Not Valid
SW & ESW (8-bit)
Not Valid
ESW (10-bit)
Response
A3
A2
A1
A0
0
0
0
0
0
LW & ELW
Word Type
L2
L1
L0
0
DR2
DR1
DR0
No Response
LW & ELW
SW & ESW (8-bit)
No Response
ESW (10-bit)
Legend
A [3:0] = Address bits.
“–” = Don’t care bit. Can be 0 or 1.
DR [2:0] = I / O direction bits. 1 = Output. All bits are set to 0
by reset / clear.
L[2:0] = Level to output on I/O if configured as outputs.
Figure 14. I/O Control Command and Response Format
REQUEST ID COMMAND AND RESPONSE
This command will cause the device ID information to be
read from internal storage and returned to the master. The
command format is found in Figure 15.
The response is sent during the next message following a
valid Request ID command to the addressed device.
Data
–
–
–
–
–
Because this is a long-word only command, there is no short
word response.
The 33784 will only act on this command if the address bits
in the command match with the address that the device was
initialized. If the addresses do not match, the device will do
nothing and no response will be generated.
Address
–
–
–
A3
A2
A1
Command
A0
0
1
0
Word Type
0
Not Valid
SW & ESW (8-bit)
Not Valid
ESW (10-bit)
Response
A3
A2
A1
A0
0
0
0
0
V3
LW & ELW
Word Type
V2
V1
V0
0
0
0
FPA
R
No Response
LW & ELW
SW & ESW (8-bit)
No Response
ESW (10-bit)
Legend
A [3:0] = Address bits. The address of the selected device.
An address value of 0000 is ignored by all devices.
V [3:0] = Device version number. The silicon version
number of the device. V0 always = 0, indicating MC33784
“–” = Don’t care bit. Can be 0 or 1.
FPAR = Some parameters in the device are trimmed by
fuses. Since these parameters can be impacted by the
state of the fuses a fuse parity is calculated and stored
during device manufacturing. When the device is powered
up the current fuse parity is checked against the stored
parity. If they do not match this bit is set.
Figure 15. Request ID Command and Response Format
33784
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Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
CLEAR COMMAND AND RESPONSE
This command will open the bus switch and reset all
registers to the reset state. The command format is found in
Figure 16. No response is generated for the clear command.
Data
–
–
–
–
The 33784 will only act on this command if the address bits
in the command match the address that the device was
initialized with, or if the address bits are 0000.
Address
–
–
–
–
–
–
Command
Word Type
A3
A2
A1
A0
0
1
1
1
LW & ELW
A3
A2
A1
A0
0
1
1
1
SW & ESW (8-bit)
A3
A2
A1
A0
0
1
1
1
ESW (10-bit)
Response
Word Type
No Response
LW & ELW
No Response
No Response
SW & ESW (8-bit)
ESW (10-bit)
Legend
A [3:0] = Address bits. The address of the selected device.
An address value of 0000 clears all devices.
“–” = Don’t care bit. Can be 0 or 1.
Figure 16. Clear Command Format and Response Format
FORMAT CONTROL COMMAND AND RESPONSE
This command allows the short-word length, the CRC
polynomial, and the CRC seed to be changed. It is also the
command needed to switch the device from the “standard”
mode to the “enhanced” mode.
The response is sent during the next message following a
valid Format Control command to the addressed device.
Because this is a long-word only command, there is no short
word response.
On power-up or following a “Clear” command, the device
uses the standard DSI short-word length (8 data bits) and
standard CRC polynomial (x4 + 1) and seed (1010).
The registers associated with Format Control default to
values that correspond to Standard DBUS operation upon
power-up, or at the issuance of a “Clear” command.
Changes made to the Format Control Register do not
become active until the 4 bits of the format selection register
are set during a single write command. It will not switch back
to Standard DBUS settings unless all 4 bits of the format
selection register are cleared by a single write.
Any attempts to change the format will be ignored while in
the enhanced mode.
The Format Control command is a long-word Command
and contains 8 bits of data which are used to determine read
or write, the specific format control register, and the data to
be written/read. The format for this command is defined in
Figure 17.
If the R/W bit is set, the value in the Data Bits will be written
to the format control register pointed to by the 3-bit format
register address. If the R/W bit is clear, the bits in the register
pointed to by the format register address will not be changed,
but the values in it will be returned in the following response
from the device. No data can be written to the reserved
registers.
The response to this command will be the data that was
written/read by the command. Attempts to write to the
reserved registers will return zeros in the data bits of the
response.
The 33784 will only act on the Format Control Command if
the address bits in the command match the address that the
device was initialized with. If the addresses do not match, the
device will do nothing and no response will be generated. The
only exception is the global address of 0000. If the address
bits in the command are 0000, the 33784 will perform all
normal functions associated with the command, but no
response will be generated.
33784
Analog Integrated Circuit Device Data
Freescale Semiconductor
23
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
Data
R/W
ADD
R2
ADD
R1
ADD
R0
Address
Data
3
Data
2
Data
1
Data
0
A3
A2
A1
Command
A0
1
0
Word Type
1
0
Not Valid
SW & ESW (8-bit)
Not Valid
ESW (10-bit)
Response
A3
A2
A1
A0
0
0
0
0
R/W
LW & ELW
Word Type
ADD
R2
ADD
R1
ADD
R0
DAT
A3
DAT
A2
DAT
A1
DAT
A0
No Response
LW & ELW
SW & ESW (8-bit)
No Response
ESW (10-bit)
Legend
A [3:0] = Address bits. The address of the selected device.
R/W = Controls if this is a read or write. Write = 1.
DATA[3:0] = Data to read from or write to in the pointed to Format
Control Register.
ADDR[2:0] = Pointer to Format control register which is to be accessed.
Figure 17. Format Control Command and Response Format
FORMAT CONTROL REGISTERS
SEED
The enhanced DSI Register locations are shown in
Figure 9. The ADDR bits in the Format Control Command
select the Format Control Register to which data is written or
from which data is read. The data is 4 bits.
The Seed is the starting value loaded into the CRC
checking registers before each transaction starts. The default
DSI seed of 1010 would be selected by loading 1010 into
control register 2. On reset or clear, the standard DSI seed is
loaded into this register.
Table 9. Format Control Registers
SHORT-WORD DATA LENGTH
Format Control
Register Address
Description
0
CRC Polynomial
1
Reserved
2
Seed
3
Reserved
4
Reserved
5
Short-Word Data Length
6
Reserved
7
Format Selection
CRC POLYNOMIAL
The CRC Taps control the feedback for the CRC
Polynomial. The MSB represents the X3 bit. The LSB
represents X0 or the value 1 if set or 0 if not set. The standard
DSI CRC of X4+1 would be obtained by loading 0001 into the
Format register 0. The X4 pin is always considered on, so
nothing has to be done for it. On a reset or clear, the standard
DSI CRC taps are loaded into these registers.
The Short-Word Data Length controls the number of bits of
data in a short word. This can be set to 8 or 10. On a reset or
clear, the value in this register defaults to 8. If a number other
than 8 or 10 is written to the register, it is ignored and the
contents of the register are not changed. The standard DSI
short-word data length would be set by loading 1000 into this
register.
FORMAT SELECTION
The Format selection determines whether the standard
DSI values will be used or the values in the Format register.
The switch to the values in the format registers occurs when
1111 is successfully written to control register 7 in a single
command. If the register is currently cleared, and one of the
data bits is not received as a logic [1], the data in the register
will remain all zeroes and the device will not use the Format
register settings. A switch back to standard DBUS occurs
when a ‘0000’ is successfully written to control register 7. If
the registers bits are all set, and one of the bits is received as
a logic [1], the value of the bits in the register will remain 1111
and the switch back to Standard DSI values will not occur.
This is done to reduce the possibility of switching operation
modes due to a corrupted command. When using the Format
Register settings, any command to change them, other than
this register back to 0000, will be ignored.
33784
24
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
COMMAND SUMMARY
are summarized in Table 11, page 26, and Table 12,
page 27. The four-bit CRC, which appended to the end of
every command and every response, has been committed.
Refer to Table 10 for a summary of the commands
available in the 33784. The responses to these commands
Table 10. Command Summary
Command Names
Hex
Description
Data (LW & ELW only)
Address
Command
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
C3
C2
C1
C0
0
Initialization
–
BSH
BSL
OD
PA3
PA2
PA1
PA0
A3
A2
A1
A0
0
0
0
0
1
Request Status
–
–
–
–
–
–
–
–
A3
A2
A1
A0
0
0
0
1
2
Request AN0
–
–
–
–
–
–
–
–
A3
A2
A1
A0
0
0
1
0
3
I /O Control
–
L2
L1
L0
–
DR2
DR1
DR0
A3
A2
A1
A0
0
0
1
1
4
Request ID
Information
–
–
–
–
–
–
–
–
A3
A2
A1
A0
0
1
0
0
5
Request AN1
–
–
–
–
–
–
–
–
A3
A2
A1
A0
0
1
0
1
6
Reserved
–
–
–
–
–
–
–
–
A3
A2
A1
A0
0
1
1
0
7
Clear
–
–
–
–
–
–
–
–
A3
A2
A1
A0
0
1
1
1
8
Reserved
–
–
–
–
–
–
–
–
A3
A2
A1
A0
1
0
0
0
9
Reserved
–
–
–
–
–
–
–
–
A3
A2
A1
A0
1
0
0
1
A
Format Control
ADDR2 ADDR1 ADDR0 DATA3 DATA2 DATA1 DATA0 A3
A2
A1
A0
1
0
1
0
B
Reserved
C
Reserved
D
Reserved
E
Reserved for test
F
Reserved
-
-
-
-
-
-
-
R/ W
–
-
–
–
-
-
-
-
-
Legend
BSH = Controls closing of the High Side Bus Switch (1 = close).
PA [3:0] = Bus Address to set the device to.
BSL = Controls closing of the Low Side Bus Switch (1 = close).
R/W = Controls if this is a read or write. Write = 1.
DR [2:0] = Direction of I /O. 1 = Output.
ADDR[2:0] = Pointer to Format Control Register that is to be accessed.
L [2:0] = Level to output on I /O if configured as outputs.
DATA[3:0] = Data to read from or write to in the pointed to Format Control
Register.
“–” = Don’t care bit. Can be 0 or 1.
OD = Oscillator dither:
0 = no dither (default)
1 = dither
33784
Analog Integrated Circuit Device Data
Freescale Semiconductor
25
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
Table 11. Long Word Response Summary
Command
Name
Hex
Description
LW & ELW
D15 D14 D13 D12 D11 D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
0
Initialization
A3
A2
A1
A0
0
0
0
0
0
BSH
BSL
0
PA3
PA2
PA1
PA0
1
Request Status
A3
A2
A1
A0
0
0
0
0
0
BSH
BSL
0
0
IO2
IO1
IO0
2
Request AN0
A3
A2
A1
A0
0
0
0
0
B9
B8
B7
B6
B5
B4
B3
B2
3
I /O Control
A3
A2
A1
A0
0
0
0
0
0
L2
L1
L0
0
DR2
DR1
DR0
4
Request ID
Information
A3
A2
A1
A0
0
0
0
0
V3
V2
V1
V0
0
0
0
FPAR
5
Request AN1
A3
A2
A1
A0
0
0
0
0
B9
B8
B7
B6
B5
B4
B3
B2
6
Reserved
No Response
7
Clear
No Response
8
Reserved
No Response
9
Reserved
No Response
A
Format Control
B
Reserved
No Response
C
Reserved
No Response
D
Reserved
No Response
E
Reserved for
test
No Response
F
Reserved
No Response
A3
A2
A1
A0
0
0
0
0
R/W ADDR2 ADDR1 ADDR0 DATA3 DATA2 DATA1 DATA0
Legend
A [3:0] = Address bits. The slave address.
PA [3:0] = Bus address to set the device to.
B [9:0] = Data bits.
V [2:0] = Version number.
BSH = Status of the High Side Bus Switch (1 = close).
R/W = Shows if last command was a read Or Write. Write = 1.
BSL = Status of the Low Side Bus Switch (1 = close).
ADDR[2:0] = Pointer to Format Control Register that was accessed.
DR [2:0] = I /O direction bits (1 = Output).
DATA[3:0] = Data in the pointed-to Format Control Register.
IO [2:0] = Logic level of I /O.
L [2:0] = Level to output on I /O if configured as outputs.
33784
26
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
Table 12. Enhanced Short-Word Response Summary
Command Names
Hex
10-Bit ESW
Description
8-Bit ESW
0
Initialization
No Response
1
Request Status
No Response
2
Request AN0
3
I /O Control
No Response
4
Request ID Information
No Response
5
Request AN1
6
Reserved
No Response
7
Clear
No Response
8
Reserved
No Response
9
Reserved
No Response
A
Format Control
No Response
B
Reserved
No Response
C
Reserved
No Response
D
Reserved
No Response
E
Reserved for test
No Response
F
Reserved
No Response
B9
B9
Legend
B8
B8
B7
B7
B6
B6
B5
B5
B4
B3
B2
B1
B0
B4
B3
B2
B1
B0
No SW or ESW response except for commands 2 and 5
B [9:0] = Data bits.
33784
Analog Integrated Circuit Device Data
Freescale Semiconductor
27
PACKAGING
PACKAGE DIMENSIONS
PACKAGING
PACKAGE DIMENSIONS
For the most current package revision, visit www.freescale.com and perform a keyword search using the “98A” listed below.
EF SUFFIX (PB-FREE)
98ASB42566B
ISSUE M
33784
28
Analog Integrated Circuit Device Data
Freescale Semiconductor
REVISION HISTORY
REVISION HISTORY
REVISION
DATE
DESCRIPTION OF CHANGES
1.0
3/2008
• Initial Release
2.0
7/2008
• Added RoHS logo to page 1, provided tRSP_R temperature parameters, page 8
3.0
11/2009
• Changed Part Number from PCZ33784EF/R2 to MCZ33784EF/R2 on page 1.
33784
Analog Integrated Circuit Device Data
Freescale Semiconductor
29
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MC33784
Rev 3.0
11/2009