Renesas RL78 Series User Manual page 589

RL78/G1D
The main processing of the slave operation is explained next.
Start serial interface IICA and wait until communication is enabled.
communication by using the communication mode flag and ready flag (processing of the stop condition and start
condition is performed by an interrupt. Here, check the status by using the flags).
The transmission operation is repeated until the master no longer returns ACK. If ACK is not returned from the master,
communication is completed.
For reception, the necessary amount of data is received. When communication is completed, ACK is not returned as
the next data. After that, the master generates a stop condition or restart condition. Exit from the communication
status occurs in this way.
No
No
No
Remarks 1. Conform to the specifications of the product that is in communication, regarding the
R01UH0515EJ0120 Rev.1.20
Dec 16, 2016
Figure 14-30. Slave Operation Flowchart (1)
START
Setting the PER0 register
Release the serial interface IICAn from the reset status and start clock suppl y .
Setting of the port used alternatively as the pin to be used.
Setting port
First, set the port to input mode and the output latch to 0 (see14.3.8 Port mode register 6 (PM6)).
IICWLn, IICWHn ← XXH Selects a transfer clock.
Sets a local address.
SVAn ← XXH
IICFn ← 0XH
Sets a start condition.
Setting IICRSVn
Setting IICCTLn1
IICCTLn0 ← 0XX011XXB
ACKEn = WTIMn = 1, SPIn = 0
IICCTLn0 ← 1XX011XXB
IICEn = 1
Set the port from input mode to output mode and enable the output of the I
Setting port
(see 14.3.8 Port mode register 6 (PM6)).
Communication
mode flag = 1?
Yes
No
Communication
direction flag = 1?
Yes
Starts
Writing IICAn
transmission.
Communication
mode flag = 1?
Yes
Communication
direction flag = 1?
Yes
No
Ready flag = 1?
Yes
Clearing ready flag
Yes
ACKDn = 1?
No
Clearing communication
mode flag
WRELn = 1
transmission and reception formats.
2. n = 0
CHAPTER 14 SERIAL INTERFACE IICA
When communication is enabled, execute
SPIEn = 1
Starts
WRELn = 1
reception.
No
Communication
mode flag = 1?
Yes
No
Communication
direction flag = 1?
Yes
No
Ready flag = 1?
Yes
Reading IICAn
Clearing ready flag
2
C bus
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