H8SX1663 datasheet(782/1158 Pages) RENESAS

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Section 15 Serial Communication Interface (SCI, IrDA, CRC)

Rev.1.00 Jun. 07, 2006 Page 730 of 1102

REJ09B0294-0100

15.7.7

Serial Data Reception (Except in Block Transfer Mode)

Data reception in smart card interface mode is similar to that in normal serial communication

interface mode. Figure 15.32 shows the data re-transfer operation during reception.

1. If a parity error is detected in receive data, the PER bit in SSR is set to 1. Here, an ERI

interrupt request is generated if the RIE bit in SCR is set to 1. Clear the PER bit to 0 before the

next parity bit is sampled.

2. For the frame in which a parity error is detected, the RDRF bit in SSR is not set to 1.

3. If no parity error is detected, the PER bit in SSR is not set to 1.

4. In this case, data is determined to have been received successfully, and the RDRF bit in SSR is

set to 1. Here, an RXI interrupt request is generated if the RIE bit in SCR is set to 1.

Figure 15.33 shows a sample flowchart for reception. All the processing steps are automatically

performed using an RXI interrupt request to activate the DTC or DMAC. In reception, setting the

RIE bit to 1 allows an RXI interrupt request to be generated when the RDRF flag is set to 1. This

activates the DTC or DMAC by an RXI request thus allowing transfer of receive data if the RXI

interrupt request is specified as a source of DTC or DMAC activation beforehand. The RDRF flag

is automatically cleared to 0 at data transfer by the DTC or DMAC. If an error occurs during

reception, i.e., either the ORER or PER flag is set to 1, a transmit/receive error interrupt (ERI)

request is generated and the error flag must be cleared. If an error occurs, the DTC or DMAC is

not activated and receive data is skipped, therefore, the number of bytes of receive data specified

in the DTC or DMAC is transferred. Even if a parity error occurs and the PER bit is set to 1 in

reception, receive data is transferred to RDR, thus allowing the data to be read.

Note:

For operations in block transfer mode, see section 15.4, Operation in Asynchronous Mode.

D0 D1 D2 D3 D4 D5 D6 D7 Dp DE

Ds D0 D1 D2 D3 D4 D5 D6 D7 Dp

(DE)

Ds D0 D1 D2 D3 D4

(n + 1) th

transfer frame

Retransfer frame

nth transfer frame

RDRF

[1]

PER

[2]

[3]

[4]

Figure 15.32 Data Re-Transfer Operation in SCI Reception Mode

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