Renesas rl78 User Manual

 

RL78/G1A 

 

CHAPTER  13   SERIAL  INTERFACE  IICA 

The processing procedure of the slave operation is as follows. 

Basically, the slave operation is event-driven.  Therefore, processing by the INTIICA0 interrupt (processing that 

must substantially change the operation status such as detection of a stop condition during communication) is 

necessary. 

In the following explanation, it is assumed that the extension code is not supported for data communication.  It is 

also assumed that the INTIICA0 interrupt servicing only performs status transition processing, and that actual data 

communication is performed by the main processing. 

 

IICA0

Interrupt servicing

Main processing

INTIICA0

Flag

Setting

Data

Setting

 

 

Therefore, data communication processing is performed by preparing the following three flags and passing them to 

the main processing instead of INTIICA0. 

 

This flag indicates the following two communication statuses. 
•  Clear mode:  

Status in which data communication is not performed 

•  Communication mode:  Status in which data communication is performed (from valid address detection to 

stop condition detection, no detection of ACK from master, address mismatch) 

 

This flag indicates that data communication is enabled.  Its function is the same as the INTIICA0 interrupt for 

ordinary data communication.  This flag is set by interrupt servicing and cleared by the main processing.  

Clear this flag by interrupt servicing when communication is started.  However, the ready flag is not set by 

interrupt servicing when the first data is transmitted.  Therefore, the first data is transmitted without the flag 

being cleared (an address match is interpreted as a request for the next data). 

 

This flag indicates the direction of communication.  Its value is the same as the TRC0 bit. 

 

R01UH0305EJ0200  Rev.2.00 

 

 

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Jul 04, 2013