33793 Datasheet, PDF (16/27 Pages) Freescale Semiconductor, Inc – Distributed System Interface (DSI) Sensor Interface

FUNCTIONAL DEVICE OPERATION
DSI COMMANDS AND RESPONSES
Table 9. Initialization Command Format
Legend
A[3:0] = Address bits. The slave address.
BS = Bus Switch Position (1 = closed).
G[1:0] = Group bits (unused).
NV = Nonvolatile Memory Write. The value of the NV bit in the slave.
PA[3:0] = Bus Address to set the device to.
X[3:0] = Cyclic Redundancy Check (CRC). The CRC as calculated by the
master.
INITIALIZATION RESPONSE
This response message is sent during the next message
following a valid Initialization command to the addressed
device. The response is shown in Table 10. Because this is a
long-word only command, the short-word response is invalid.
Table 10. Initialization Response Format
High Byte
A3 A2 A1 A0 0
0
0 BF NV
Legend
A[3:0] = Address bits. The slave address.
BF = Bus Fault. Bus out short to battery detected.
BS = Bus Switch Position (1 = closed).
G[1:0] = Group bits (unused).
Low Byte
CRC
BS G1 G0 PA3 PA2 PA1 PA0 X3 X2 X1 X0
NV = Nonvolatile Memory Write. The value of the NV bit in the slave.
PA[3:0] = Bus Address to set the device to.
X[3:0] = Cyclic Redundancy Check (CRC). The CRC as calculated by
the slave.
REQUEST STATUS COMMAND
This command will cause the addressed device to return
the status of the NV, U, and BS bits and the logic levels of the
I/O and LOGICOUT. The command format is found in
Table 11.
Table 11. Request Status Command Format
Data
Address
Command
CRC
–
–
–
–
–
–
–
– A3
Legend
A[3:0] = Address bits. The address of the selected device. An
address value of "0000" is ignored by all devices.
A2 A1 A0 0 0 0 1 X3 X2 X1 X0
X[3:0] = Cyclic Redundancy Check (CRC). The CRC as calculated by the
master.
REQUEST STATUS RESPONSE
This response message is sent during the next message
following a valid Request Status command to the addressed
device. The response format is found in Table 12. The high
byte is omitted during the short-word response. No response
is generated if the command address field was $0.
Table 12. Request Status Response Format
High Byte
A3 A2 A1 A0 0 0 0 0 NV
Legend
A[3:0] = Address bits. The slave address.
BS = Bus Switch Position (1 = closed).
LO = Logic out driven level.
IO[3:0] = Values at logic I/Os.
Low Byte
CRC
U
LO BS IO3 IO2 IO1 IO0 X3 X2 X1 X0
NV = Nonvolatile Memory Write. The value of the NV bit in the slave.
U = Undervoltage indicated true by a “1”.
X[3:0] = Cyclic Redundancy Check (CRC). The CRC as calculated by the
slave.
REQUEST VALUE n COMMAND
This command will cause the analog level at one of the
four I/O lines to be measured and returned on the following
command. The command format is found in Table 13. The
analog input measured is defined in Table 14.
33793
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Analog Integrated Circuit Device Data
Freescale Semiconductor