SH7052 datasheet(516/919 Pages) RENESAS

516 / 919 page

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Receiving Serial Data (Synchronous Mode): Figures 14.21 and 14.22 show sample flowcharts

for receiving serial data. When switching from asynchronous mode to synchronous mode, make

sure that ORER, PER, and FER are cleared to 0. If PER or FER is set to 1, the RDRF bit will not

be set and both transmitting and receiving will be disabled.

The procedure for receiving serial data is as follows (the steps correspond to the numbers in the

flowchart):

1. SCI initialization: Set the RxD pin using the PFC.

2. Receive error handling: If a receive error occurs, read the ORER bit in SSR to identify the

error. After executing the necessary error handling, clear ORER to 0. Transmitting/receiving

cannot resume if ORER remains set to 1.

3. SCI status check and receive data read: Read the serial status register (SSR), check that RDRF

is set to 1, then read receive data from the receive data register (RDR) and clear RDRF to 0.

The RXI interrupt can also be used to determine if the RDRF bit has changed from 0 to 1.

4. Continue receiving serial data: Read RDR, and clear RDRF to 0 before the MSB (bit 7) of the

current frame is received. If the DMAC is started by a receive-data-full interrupt (RXI) to read

RDR, the RDRF bit is cleared automatically so this step is unnecessary.

SH7052 Datasheet(PDF) 516 Page - Renesas Technology Corp