H8S2245 datasheet(542/818 Pages) RENESAS

542 / 818 page

Section 13 Smart Card Interface

Rev.3.00 Mar. 26, 2007 Page 500 of 772

REJ09B0355-0300

Retransfer Operations

Retransfer operations are performed by the SCI in receive mode and transmit mode as described

below.

• Retransfer operation when SCI is in receive mode

Figure 13.11 illustrates the retransfer operation when the SCI is in receive mode.

[1] If an error is found when the received parity bit is checked, the PER bit in SSR is

automatically set to 1. If the RIE bit in SCR is enabled at this time, an ERI interrupt request is

generated. The PER bit in SSR should be kept cleared to 0 until the next parity bit is sampled.

[2] The RDRF bit in SSR is not set for a frame in which an error has occurred.

[3] If no error is found when the received parity bit is checked, the PER bit in SSR is not set to 1.

[4] If no error is found when the received parity bit is checked, the receive operation is judged to

have been completed normally, and the RDRF flag in SSR is automatically set to 1. If the RIE

bit in SCR is enabled at this time, an RXI interrupt request is generated.

If DTC data transfer by an RXI source is enabled, the contents of RDR can be read

automatically. When the RDR data is read by the DTC, the RDRF flag is automatically cleared

to 0 if DISEL in DTC is 0 and the transfer counter value is not 0.

[5] When a normal frame is received, the pin retains the high-impedance state at the timing for

error signal transmission.

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

Transfer

frame n+1

Retransferred frame

nth transfer frame

RDRF

[1]

PER

[2]

[3]

[4]

Figure 13.11 Retransfer Operation in SCI Receive Mode

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