Datasheet
RL78/L12    CHAPTER 12 SERIAL ARRAY UNIT 
R01UH0330EJ0200 Rev.2.00      464 
Dec 13, 2013 
Figure 12-66. Flowchart of Slave Transmission/Reception (in Single- Transmission/Reception Mode) 
Starting CSI communication
Write STmn bit to 1 
Transmission/reception 
next data? 
Yes 
No 
End of communication 
Reading receive data to 
SIOp (=SDRmn[7:0])
Transmission/reception 
completed? 
No 
Yes 
Writing transmit data to 
SIOp (=SDRmn[7:0]) 
Start communication when master start providing the
clock
When transfer end interrupt is generated, it moves to
interrupt processing routine
Wait for transmission/reception 
completes
For the initial setting, refer to Figure 12-62 
(Select Transfer end interrupt)
SAU default setting
Setting 
transmission/reception data
Setting storage area and number of data for transmission/reception data 
(Storage area, Transmission/reception data pointer, Number of communication data 
and Communication end flag are optionally set on the internal RAM by the software) 
RETI 
Transfer end interrupt
Enables interrupt 
Clear interrupt request flag (XXIF), reset interrupt mask (XXMK) and set 
interrupt enable (EI).
Disable interrupt (MASK)
Read receive data and write it to storage area.    Update 
receive data pointer.
Update the number of communication data and confirm 
if next transmission/reception data is available 
Read transmit data from storage area and write it to SIOp. 
Update transmit data pointer. 
Main routine Main routineInterrupt processing routine
Caution  Be sure to set transmit data to the SlOp register before the clock from the master is started. 
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