Read Operation - NEC mPD71312 User Manual

4.4 Read Operation

The processing procedure, format, and operation of reading the LCD controller/driver via the I
explained below.
The LCD controller/driver register to be accessed can be specified with the slave ID and address (see Figure 3-3).
(1) Processing procedure
Remark
Downloaded from Elcodis.com electronic components distributor
CHAPTER 4 I
Figure 4-11. Processing procedure of Read Operation
CPU side (master) CPU side (master)
ST generation ST generation
Slave ID transmission Slave ID transmission
No No
ACK reception ACK reception
Yes Yes
Address transmission Address transmission
No No
ACK reception ACK reception
Yes Yes
RST generation RST generation
Slave ID transmission Slave ID transmission
No No
ACK reception ACK reception
Yes Yes
RD reception RD reception
Yes Yes
ACK transmission ACK transmission
No No
SP generation SP generation
End End
ST: Start condition
RST: Restart condition
SP: Stop condition
2
C COMMUNICATIONS
LCD controller/driver side (slave) LCD controller/driver side (slave)
Transfer direction Transfer direction
ST detected? ST detected?
Slave ID reception Slave ID reception
ACK transmission ACK transmission
Address reception Address reception
ACK transmission ACK transmission
RST detected? RST detected?
Slave ID reception Slave ID reception
ACK transmission ACK transmission
RD transmission RD transmission
ACK reception ACK reception
User's Manual U18438EJ2V0UD
2
C bus interface are
No No
Yes Yes
No No
ID matched? ID matched?
Yes Yes
ACK' — M ACK' — M
No No
Yes Yes
No No
ID matched? ID matched?
Yes Yes
Yes Yes
No No
No No
SP detection SP detection
Yes Yes
End End
57