Datasheet

78K0/Ix2 CHAPTER 15 SERIAL INTERFACE IICA
R01UH0010EJ0500 Rev.5.00 510
Feb 28, 2012
Figure 15-28. Communication Reservation Protocol
DI
SET1 STT0
Define communication
reservation
Wait
MSTS0 = 0?
(Communication reservation)
Note 2
Yes
No
(Generate start condition)
Cancel communication
reservation
MOV IICA, #××H
EI
Sets STT0 flag (communication reservation)
Defines that communication reservation is in effect
(defines and sets user flag to any part of RAM)
Secures wait time
Note 1
by software.
Confirmation of communication reservation
Clear user flag
IICA write operation
Notes 1. The wait time is calculated as follows.
(IICWL setting value + IICWH setting value + 4) + t
F  2  fPRS [clocks]
2. The communication reservation operation executes a write to the IICA shift register (IICA) when a stop
condition interrupt request occurs.
Remark STT0: Bit 1 of IICA control register 0 (IICACTL0)
MSTS0: Bit 7 of IICA status register 0 (IICAS0)
IICA: IICA shift register
IICWL: IICA low-level width setting register
IICWH: IICA high-level width setting register
tF: SDAA0 and SCLA0 signal falling times
(refer to CHAPTER 28 ELECTRICAL SPECIFICATIONS)
f
PRS: Peripheral hardware clock frequency