HD6432351 datasheet(673/1025 Pages) RENESAS

673 / 1025 page

Section 14 Smart Card Interface

Rev. 3.00 Sep 15, 2006 page 639 of 988

REJ09B0330-0300

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 14.11 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 DMAC or 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 DMAC or DTC, the RDRF flag is

automatically cleared to 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 14.11 Retransfer Operation in SCI Receive Mode

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