Datasheet

Rev. 3.00, 03/04, page 420 of 830

14.9 Interrupt Sources

14.9.1 Interrupts in Normal Serial Communication Interface Mode

Table 14.13 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.

Table 14.14 SCI Interrupt Sources

Channel Name Interrupt Source Interrupt Flag DTC Activation Priority

ERI0 Receive error ORER, FER, PER Not possible High

RXI0 Receive data full RDRF Possible

TXI0 Transmit data empty TDRE Possible

TEI0 Transmit end TEND Not possible

ERI1 Receive error ORER, FER, PER Not possible

RXI1 Receive data full RDRF Possible

TXI1 Transmit data empty TDRE Possible

TEI1 Transmit end TEND Not possible

ERI2 Receive error ORER, FER, PER Not possible

RXI2 Receive data full RDRF Possible

TXI2 Transmit data empty TDRE Possible

TEI2 Transmit end TEND Not possible Low