R01UH0822EJ0100 Rev.1.00
Page 712 of 1041
Jul 31, 2019
RX13T Group
23. Serial Communications Interface (SCIg, SCIh)
23.12.3
Interrupts in Smart Card Interface Mode
lists interrupt sources in smart card interface mode. A transmit end interrupt (TEI) request cannot be used in
this mode.
Table 23.32
SCI Interrupt Sources
Data transmission/reception using the DTC 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 allowing transfer of transmit data if the TXI request is specified beforehand as a
source of DTC activation. The TEND flag is automatically set to 0 when the DTC 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 is not activated. Therefore, the SCI and DTC 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, be sure to make settings to enable the DTC before making SCI settings.
For DTC settings, refer to
section 16, Data Transfer Controller (DTCb)
In reception, an RXI interrupt request is generated when receive data is set to RDR. This RXI interrupt request activates
the DTC allowing transfer of receive data if the RXI request is specified beforehand as a source of DTC activation. If an
error occurs, the error flag is set. Therefore, the DTC 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
ERI
Receive error or error signal detection
ORER, PER, or ERS
Not possible
RXI
Receive data full
—
Possible
TXI
Transmit data empty
TEND
Possible