Datasheet

Section 12 Serial Communication Interface
Rev.7.00 Dec. 24, 2008 Page 440 of 698
REJ09B0074-0700
12.9 Interrupts
12.9.1 Interrupts in Normal Serial Communication Interface Mode
Table 12.12 shows the interrupt sources in normal serial communication interface mode. A
different interrupt vector is assigned to each interrupt source, and individual interrupt sources can
be enabled or disabled using the enable bits in SCR.
When the TDRE flag in SSR is set to 1, a TXI interrupt request is generated. When the TEND flag
in SSR is set to 1, a TEI interrupt request is generated. A TXI interrupt can activate the DMAC to
perform data transfer. The TDRE flag is cleared to 0 automatically when data is transferred by the
DMAC.
When the RDRF flag in SSR is set to 1, an RXI interrupt request is generated. When the ORER,
PER, or FER flag in SSR is set to 1, an ERI interrupt request is generated. An RXI interrupt
request can activate the DMAC to transfer data. The RDRF flag is cleared to 0 automatically when
data is transferred by the DMAC.
A TEI interrupt is requested when the TEND flag is set to 1 and the TEIE bit is set to 1. If a TEI
interrupt and a TXI interrupt are requested simultaneously, the TXI interrupt has priority for
acceptance. However, if the TDRE and TEND flags are cleared simultaneously by the TXI
interrupt routine, the SCI cannot branch to the TEI interrupt routine later.
Table 12.12 SCI Interrupt Sources
Channel Name Interrupt Source Interrupt Flag DMAC Activation Priority*
ERI0 Receive Error ORER, FER, PER Not possible High
RXI0 Receive Data Full RDRF Possible
TXI0 Transmit Data Empty TDRE Possible
0
TEI0 Transmission End TEND Not possible
2 ERI2 Receive Error ORER, FER, PER Not possible
RXI2 Receive Data Full RDRF Not possible
TXI2 Transmit Data Empty TDRE Not possible
TEI2 Transmission End TEND Not possible Low
Note: * This table shows the initial state immediately after a reset. The relative channel priorities
can be changed by the interrupt controller.