wms7202 Winbond Electronics Corp America, wms7202 Datasheet - Page 15

• Manufacturer Part Number: wms7202
• Description: 256-tap Dual-channel Non-volatile Digital
• Manufacturer: Winbond Electronics Corp America

Inst.
No.
4
2
1
The contents of the tap register for any channel or any NVMEM location can be read back through the
SDO pin. When a command is sent, the data is clocked out on the falling edge of the clock. Since
daisy-chain operation requires data from one command to be clocked out when the next command
arrives, any read command must be followed by another command to get the correct data on the SDO
pin.
To read the contents of either the tap register or a NVMEM location, the following sequence must be
followed.
Command
Name:
Read
NVMEM
Read Tap
Register
NOP to
Read
Register
1. Send the desired read command (#2 or #4) to select the register to read
2. Send another command such as NOP and read the SDO pin on the falling edge of the clock.
7.8.5 Reading Tap Registers and NVMEM Locations
The other command could be any command, but to make sure that the chip does not change
anything, send either another Read command or a NOP command (#1).
Command Byte
1 0 1 0 A3 A2 A1 A0
1 1 0 0 x x A1 A0
0 0 0 0 x x x x
TABLE 9 – READING THE TAP REGISTERS
Data Byte 1
x x x x x x x x
x x x x x x x x
x x x x x x x D8
- 15 -
Data Byte 2
D7 D6 D5 D4 D3 D2 D1 D0
x x x x x x x x
x x x x x x x x
Publication Release Date: January 2003
WMS7202
Comment
Read the value of the
selected NVMEM
location
Read the value of the
selected tap register
Output data to SDO
pin
Revision 1.1