RL78/G1P
CHAPTER 12 SERIAL INTERFACE IICA
R01UH0895EJ0100 Rev.1.00
513
Nov 29, 2019
An example of the processing procedure of the slave with the INTIICAn interrupt is explained below (processing is
performed assuming that no extension code is used). The INTIICAn interrupt checks the status, and the following
operations are performed.
<1> Communication is stopped if the stop condition is issued.
<2> If the start condition is issued, the address is checked and communication is completed if the address does
not match. If the address matches, the communication mode is set, wait is cancelled, and processing returns
from the interrupt (the ready flag is cleared).
<3> For data transmit/receive, only the ready flag is set. Processing returns from the interrupt with the I
2
C bus
remaining in the wait state.
Remark
<1> to <3> above correspond to <1> to <3> in Figure 12-31 Slave Operation Flowchart (2).
Figure 12-31. Slave Operation Flowchart (2)
Yes
Yes
Yes
No
No
No
INTIICAn generated
Set ready flag
Interrupt servicing completed
SPDn = 1?
STDn = 1?
COIn = 1?
Communication direction flag
TRCn
Set communication mode flag
Clear ready flag
Clear communication direction
flag, ready flag, and
communication mode flag
<1>
<2>
<3>
12.5.17 Timing of I
2
C interrupt request (INTIICAn) occurrence
The timing of transmitting or receiving data and generation of interrupt request signal INTIICAn, and the value of the
IICA status register n (IICSn) when the INTIICAn signal is generated are shown below.
Remarks 1.
ST:
Start
condition
AD6 to AD0: Address
R/W:
Transfer direction specification
ACK:
Acknowledge
D7 to D0:
Data
SP:
Stop
condition
2.
n = 0, 1