Datasheet

Section 15 Serial Communication Interface (SCI)
Rev. 3.00 Sep. 28, 2009 Page 460 of 910
REJ09B0350-0300
15.8.2 Interrupts in Smart Card Interface Mode
Table 15.14 shows the interrupt sources in smart card interface mode. A TEI interrupt request
cannot be used in this mode.
Table 15.14 SCI Interrupt Sources
Channel Name Interrupt Source Interrupt Flag Priority
ERI1 Receive error, error signal
detection
ORER, PER, ERS
RXI1 Receive data full RDRF
1
TXI1 Transmit data empty TEND
ERI2 Receive error, error signal
detection
ORER, PER, ERS 2
RXI2 Receive data full RDRF
High
TXI2 Transmit data empty TEND Low
In transmission, the TEND and TDRE flags in SSR are simultaneously set to 1, thus generating a
TXI interrupt request. If an error occurs, the SCI automatically re-transmits the same data. During
re-transmission, the TEND flag remains 0. Therefore, the SCI automatically transmits the
specified number of bytes, including re-transmission in the case of error. 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.
In reception, an RXI interrupt request is generated when the RDRF flag in SSR is set to 1. If an
error occurs, the RDRF flag is not set but the error flag is set. Therefore, an ERI interrupt request
is issued to the CPU instead; the error flag must be cleared.