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R01UH0823EJ0100 Rev.1.00 Page 1094 of 1823

Jul 31, 2019

RX23W Group 33. Serial Communications Interface (SCIg, SCIh)

33.12.3 Interrupts in Smart Card Interface Mode

Table 33.32 lists interrupt sources in smart card interface mode. A transmit end interrupt (TEI) request cannot be used in

this mode.

Table 33.32 SCI Interrupt Sources

Data transmission/reception using the DTC or DMAC is also possible in smart card interface mode, similar to in the

normal SCI mode. In transmission, when the TEND flag in the SSR register is set to 1, a TXI interrupt request is

generated. This TXI interrupt request activates the DTC or DMAC allowing transfer of transmit data if the TXI request is

specified beforehand as a source of DTC or DMAC activation. The TEND flag is automatically set to 0 when the DTC or

DMAC transfers the data.

If an error occurs, the SCI automatically retransmits the same data. During the retransmission, the TEND flag is kept to 0

and the DTC or DMAC is not activated. Therefore, the SCI and DTC or DMAC automatically transmit the specified

number of bytes, including retransmission in the case of error occurrence. However, the ERS flag in the SSR register is

not automatically cleared to 0 at error occurrence. Therefore, the ERS flag must be cleared by previously setting the RIE

bit in the SCR register to 1 to enable an ERI interrupt request to be generated at error occurrence.

When transmitting/receiving data using the DTC or DMAC, be sure to make settings to enable the DTC or DMAC

before making SCI settings. For DTC or DMAC settings, refer to

section 19, Data Transfer Controller (DTCa) and

section 18, DMA Controller (DMACA).

In reception, an RXI interrupt request is generated when receive data is set to RDR. This RXI interrupt request activates

the DTC or DMAC allowing transfer of receive data if the RXI request is specified beforehand as a source of DTC or

DMAC activation. If an error occurs, the error flag is set. Therefore, the DTC or DMAC is not activated and an ERI

interrupt request is issued to the CPU instead; the error flag must be cleared.

Name Interrupt Source Interrupt Flag DTC Activation DMAC Activation

ERI Receive error or error signal detection ORER, PER, or ERS Not possible Not possible

RXI Receive data full — Possible Possible

TXI Transmit data empty TEND Possible Possible

Renesas RX Series User Manual

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