Renesas rl78 User Manual

RL78/G1A

CHAPTER 13 SERIAL INTERFACE IICA

The meanings of <7> to <15> in (3) Data ~ data ~ stop condition in Figure 13-32 are explained below.

<7> After data transfer is completed, because of ACKE0 = 1, the slave device sends an ACK by hardware to the

master device. The ACK is detected by the master device (ACKD0 = 1) at the rising edge of the 9th clock.

<8> The master device and slave device set a wait status (SCLA0 = 0) at the falling edge of the 9th clock, and

both the master device and slave device issue an interrupt (INTIICA0: end of transfer).

<9> The master device writes the data to transmit to the IICA shift register 0 (IICA0) and releases the wait

status that it set by the master device.

<10> The slave device reads the received data and releases the wait status (WREL0 = 1). The master device

then starts transferring data to the slave device.

<11> When data transfer is complete, the slave device (ACKE0 =1) sends an ACK by hardware to the master

device. The ACK is detected by the master device (ACKD0 = 1) at the rising edge of the 9th clock.

<12> The master device and slave device set a wait status (SCLA0 = 0) at the falling edge of the 9th clock, and

both the master device and slave device issue an interrupt (INTIICA0: end of transfer).

<13> The slave device reads the received data and releases the wait status (WREL0 = 1).

<14> By the master device setting a stop condition trigger (SPT0 = 1), the bus data line is cleared (SDAA0 = 0)

and the bus clock line is set (SCLA0 = 1). After the stop condition setup time has elapsed, by setting the

bus data line (SDAA0 = 1), the stop condition is then generated (i.e. SCLA0 =1 changes SDAA0 from 0 to

1).

<15> When a stop condition is generated, the slave device detects the stop condition and issues an interrupt

(INTIICA0: stop condition).

Remark <1> to <15> in Figure 13-32 represent the entire procedure for communicating data using the I

C bus.

Figure 13-32 (1) Start condition ~ address ~ data shows the processing from <1> to <6>, Figure 13-32

(2) Address ~ data ~ data shows the processing from <3> to <10>, and Figure 13-32 (3) Data ~ data ~

stop condition shows the processing from <7> to <15>.

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Jul 04, 2013