Interrupt Sources; Interrupts In Normal Serial Communication Interface Mode - Renesas H8S/2100 Series Hardware Manual

6-bit single-chip microcomputer

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Section 14 Serial Communication Interface (SCI)

Interrupt Sources

Table 14.12 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.

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.

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 14.12 SCI Interrupt Sources

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Interrupt Source

Receive error

Receive data full

Transmit data empty

Transmit end

Interrupt Flag

ORER, FER, PER