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16.9
Interrupt Sources
16.9.1
Interrupts in Normal Serial Communication Interface Mode
Table 16.13 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 DTC to
allow data transfer. The TDRE flag is automatically cleared to 0 at data transfer by the DTC.
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 can
activate the DTC to allow data transfer. The RDRF flag is automatically cleared to 0 at data
transfer by the DTC.
A TEI interrupt is requested when the TEND flag is set to 1 while 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, note that if the TDRE and TEND flags are cleared simultaneously by the
TXI interrupt routine, the SCI cannot branch to the TEI interrupt routine later.
When the DTE bit in TDRE in SCIDTER_0 and SCIDTER_2 is 1, TXI0 and TXI2 interrupts are
masked, and when the DTE bit in RDRF is 1, RXI0 and RXI2 interrupts are masked.
Section 16 Serial Communication Interface (SCI, IrDA, and CRC)
Rev. 3.00 Jan 25, 2006 page 459 of 872
REJ09B0286-0300
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