33784 Datasheet, PDF (20/30 Pages) Freescale Semiconductor, Inc – DSI 2.02 Sensor Interface

FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
BUSIN
Frame
Threshold
End of
Request ANx
Command
All values are approximate and
are not production tested.
ADC
Enable
ADC
Sampling
Enabled
Disabled
4.6μs
Sampling
Not Sampling
13.6μs
7.4μs
1.6μs
ADC
Conversion
Completed
4.4μs
0.1μs
Figure 11. Approximate ADC Conversion Timing
Conversion
Complete
Data
Address
Command
– – – – – – – – A3 A2 A1 A0 0 0 1 0
A3 A2 A1 A0 0 0 1 0
– – A3 A2 A1 A0 0 0 1 0
Word Type
LW & ELW
SW & ESW (8-bit)
ESW (10-bit)
Response
A3 A2 A1 A0 0 0 0 0 B9 B8 B7 B6 B5 B4 B3 B2
B9 B8 B7 B6 B5 B4 B3 B2
B9 B8 B7 B6 B5 B4 B3 B2 B1 B0
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.
B [9:0] = Measured value.
Figure 12. Request AN0 Command and Response Format
Word Type
LW & ELW
SW & ESW (8-bit)
ESW (10-bit)
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