Datasheet

Rev. 3.00, 03/04, page 421 of 830
14.9.2 Interrupts in Smart Card Interface Mode
Table 14.15 shows the interrupt sources in smart card interface mode. A TEI interrupt request
cannot be used in this mode.
Table 14.15 SCI Interrupt Sources
Channel Name Interrupt Source Interrupt Flag DTC Activation Priority
ERI0 Receive error, error
signal detection
ORER, PER, ERS Not possible High
RXI0 Receive data full RDRF Possible
0
TXI0 Transmit data empty TEND Possible
ERI1 Receive error, error
signal detection
ORER, PER, ERS Not possible
RXI1 Receive data full RDRF Possible
1
TXI1 Transmit data empty TEND Possible
ERI2 Receive error, error
signal detection
ORER, PER, ERS Not possible
RXI2 Receive data full RDRF Possible
2
TXI2 Transmit data empty TEND Possible Low
Data transmission/reception using the DTC is also possible in smart card interface mode, similar
to in the normal SCI mode. In transmission, the TEND and TDRE flags in SSR are simultaneously
set to 1, thus generating a TXI interrupt request. This activates the DTC by a TXI interrupt request
thus allowing transfer of transmit data if the TXI interrupt request is specified as a source of DTC
activation beforehand. The TDRE and TEND flags are automatically cleared to 0 at data transfer
by the DTC. If an error occurs, the SCI automatically re-transmits the same data. During re-
transmission, the TEND flag remains as 0, thus not activating the DTC. Therefore, the SCI and
DTC automatically transmit the specified number of bytes, including re-transmission in the case of
error occurrence. However, the ERS flag in SSR, which is set at error occurrence, is not
automatically cleared; the ERS flag must be cleared by previously setting the RIE bit in SCR to 1
to enable an ERI interrupt request to be generated at error occurrence.
When transmitting/receiving data using the DTC, be sure to set and enable the DTC prior to
making SCI settings. For DTC settings, see section 7, Data Transfer Controller (DTC).
In reception, an RXI interrupt request is generated when the RDRF flag in SSR is set to 1. This
activates the DTC by an RXI interrupt request thus allowing transfer of receive data if the RXI
interrupt request is specified as a source of DTC activation beforehand. The RDRF flag is
automatically cleared to 0 at data transfer by the DTC. If an error occurs, the RDRF flag is not set
but 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.