wms7204 Winbond Electronics Corp America, wms7204 Datasheet - Page 14

• Manufacturer Part Number: wms7204
• Description: 256-tap Quad-channel Non-volatile Digital Potentiometer
• Manufacturer: Winbond Electronics Corp America

Inst.
No.
11
10
13
1
The chip is in SLEEP mode after:
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.
The commands above control the entire chip. There is no way to independently power on or off
individual potentiometers.
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
1. Take the chip out of SLEEP mode.
2. Check that the write protect is set correctly if writing to NVMEM.
3. Check that R/B is HIGH before issuing command.
4. Pull the CS pin LOW before sending data to the device.
5. 24 clock pulses are sent for each command. SDI must be valid on the rising edge of the clock,
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
x
x
x
Command Name:
Wake Up
Sleep
Power on Reset
NOP
7.8.1 Sending a Command
SDO is valid on the falling edge of the clock or CS .
command.
7.8.2 Wake Up/Sleep/Power Commands
V
A Power on Reset command is sent
A SLEEP command is sent
7.8.3 Write to Tap Register (TR)
DD
is applied
Command Byte
0 0 0 1 x x x x
1 0 0 0 x x x x
1 0 0 1 x x x x
0 0 0 0 x x x x
TABLE 6 – POWER RELATED COMMANDS
x x x x x x x x
x x x x x x x x
x x x x x x x x
x x x x x x x x
Data Byte 1
- 14 -
x x x x x x x x
Data Byte 2
x x x x x x x x
x x x x x x x x
x x x x x x x x
Comment
Wake Up entire chip
Send chip into power save
mode
Reset Chip
Dummy instruction
WMS7204