WMS7202
Publication Release Date: January 2003
- 13 - Revision 1.1
5. 24 clock pulses are sent for each command. SDI must be valid on the rising edge of the clock,
SDO is valid on the falling edge of the clock or
CS .
6. Take
CS HIGH after the command has completed.
7. If command 2, 4, 5, 6 or 7 is sent, wait for the R/B pin to go HIGH before sending the next
command.
7.8.2 Wake Up/Sleep/Power Commands
The chip is in SLEEP mode after:
• V
DD
is applied
• A Power on Reset command is sent
• A SLEEP command is sent
Before any operations can be performed the WAKE UP command must be sent.
When a SLEEP command is sent, the chip retains its resistor settings as long as the chip is powered
up but cannot accept any other commands than a WAKE UP command.
TABLE 6 – POWER RELATED COMMANDS
Inst.
No.
Command
Name:
Command Byte Data Byte 1 Data Byte 2 Comment
11 Wake Up 0 0 0 1 x x x x x x x x x x x x x x x x x x x x Wake Up entire chip
10 Sleep 1 0 0 0 x x x x x x x x x x x x x x x x x x x x Send chip into power
save mode
13 Power on Reset 1 0 0 1 x x x x x x x x x x x x x x x x x x x x Reset Chip
1 NOP 0 0 0 0 x x x x x x x x x x x x x x x x x x x x Dummy instruction
The commands above control the entire chip. There is no way to independently power on or off
individual potentiometers.
7.8.3 Write to Tap Register (TR)
The microcontroller can write a value directly into the tap register or send an increment or decrement
command to control the tap register. Alternatively, the contents of an NVMEM location can be written
to the tap register. The only way to change the output buffer mode is to write the desired value of bit
D8 into an NVMEM location and then load the corresponding NVMEM location into the tap register.
