Interrupt Sources; Interrupts In Normal Serial Communication Interface Mode; Table 12.12 Sci Interrupt Sources - Renesas H8SX/1500 Series Hardware Manual

Section 12 Serial Communication Interface (SCI)
12.8

Interrupt Sources

12.8.1

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 request can activate the
DMAC to allow data transfer. The TDRE flag is automatically cleared to 0 at data transfer 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 can
activate the DMAC to allow data transfer. The RDRF flag is automatically cleared to 0 at data
transfer by the DMAC.
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 to 0 simultaneously by
the TXI interrupt processing routine, the SCI cannot branch to the TEI interrupt processing routine
later.

Table 12.12 SCI Interrupt Sources

Name Interrupt Source
ERI Receive error
RXI Receive data full
TXI Transmit data empty
TEI Transmit end
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Interrupt Flag
ORER, FER, or PER
RDRF
TDRE
TEND
DMAC Activation
Not possible
Possible
Possible
Not possible
Priority
High
Low