33784 Datasheet, PDF (19/30 Pages) Freescale Semiconductor, Inc – DSI 2.02 Sensor Interface

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 short-
word response.
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.
Data
Address
Command
– – – – – – – – A3 A2 A1 A0 0 0 0 1
Not Valid
Not Valid
Word Type
LW & ELW
SW & ESW (8-bit)
ESW (10-bit)
Response
A3 A2 A1 A0 0 0 0 0 0 BSH BSL 0 0 IO2 IO1 IO0
No Response
No Response
Legend
A [3:0] = Address bits. The address of the selected device.
An address value of 0000 is ignored by all devices.
BSH = High Side Bus switch position (1 = closed).
BSL = Low Side Bus switch position (1 = closed).
“–” = Don’t care bit. Can be 0 or 1.
IO [2:0] = Values at logic I /Os.
Figure 10. Request Status Command and Response Format
Word Type
LW & ELW
SW & ESW (8-bit)
ESW (10-bit)
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.
Analog Integrated Circuit Device Data
Freescale Semiconductor
33784
19