wms7202 Winbond Electronics Corp America, wms7202 Datasheet - Page 9

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

Multiple devices can be controlled by the same bus without the need for extra CS lines from the
microcontroller by daisy chaining the devices with the SDO of the first device connected to SDI of the
next device as shown in figure 3
A complete command is 24 bits including the instruction and the two data bytes. When shifting 24 bits
in to the first device in the chain, the 24 bits of the previous command will be shifted out. So to set up
two devices in a daisy chain, a total of 48 bits must be sent where the first 24 bits will be shifted out to
the second device and the 24 bits shifted in last will remain in the first device.
2. Command and data for device 1 is shifted into device 1. Now Device 1 and 2 are correctly set
1. Command and data for device 2 is shifted into device 1; this will propagate to Device 2 when
7.5. D
up
the next 24 bits are shifted in.
Micro
controller
AISY
C
HAIN
Command 2
Command 1
Device
Device
CLK
SDO
CS
FIGURE 4 – DAISY CHAIN COMMAND EXAMPLE
FIGURE 3 – DAISY CHAIN CONFIGURATION
SDI SDO
Data
Data
Command A
CS
CLK
Device
Device
Device
xx
2
1
Data
Data
- 9 -
Data
2
1
SDI SDO
CS
CLK
Device
xx
2
Data
Publication Release Date: January 2003
xx
2
SDI SDO
V
CS
CLK
Device
DD
WMS7202
Revision 1.1