H8SSLASH2218 datasheet(473/750 Pages) RENESAS

473 / 750 page

Section 12 Serial Communication Interface

Rev.6.00 Jun. 03, 2008 Page 425 of 698

REJ09B0074-0600

Yes

<End>

[1]

Initialization

Start reception

[2]

Yes

Read RDRF flag in SSR

[4]

[5]

Clear RE bit in SCR to 0

Error processing

(Continued below)

[3]

Read receive data in RDR, and

clear RDRF flag in SSR to 0

Yes

ORER = 1

RDRF = 1

All data received?

Read ORER flag in SSR

<End>

Error processing

Overrun error processing

Clear ORER flag in SSR to 0

[3]

[1]

SCI initialization:

The RxD pin is automatically designated as

the receive data input pin.

[2]

[3] Receive error processing:

If a receive error occurs, read the ORER

flag in SSR, and after performing the

appropriate error processing, clear the

ORER flag to 0. Transfer cannot be

resumed if the ORER flag is set to 1.

[4]

SCI status check and receive data read:

Read SSR and check that the RDRF flag is

set to 1, then read the receive data in RDR

and clear the RDRF flag to 0.

Transition of the RDRF flag from 0 to 1 can

also be identified by an RXI interrupt.

[5]

Serial reception continuation procedure:

To continue serial reception, before the

MSB (bit 7) of the current frame is received,

reading the RDRF flag, reading RDR, and

clearing the RDRF flag to 0 should be

finished. The RDRF flag is cleared

automatically when the DMAC is activated

by a receive data full interrupt (RXI) request

and the RDR value is read.

Figure 12.22 Sample Serial Data Reception Flowchart

12.6.5

Simultaneous Serial Data Transmission and Reception

(Clocked Synchronous Mode)

Figure 12.23 shows a sample flowchart for simultaneous serial transmit and receive operations.

The following procedure should be used for simultaneous serial data transmit and receive

operations. To switch from transmit mode to simultaneous transmit and receive mode, after

checking that the SCI has finished transmission and the TDRE and TEND flags are set to 1, clear

TE to 0. Then simultaneously set TE and RE to 1 with a single instruction. To switch from receive

mode to simultaneous transmit and receive mode, after checking that the SCI has finished

reception, clear RE to 0. Then after checking that the RDRF and receive error flags (ORER, FER,

and PER) are cleared to 0, simultaneously set TE and RE to 1 with a single instruction.

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