Sci Interrupts - Hitachi H8/3022 Hardware Manual

11.4 SCI Interrupts

The SCI has four interrupt request sources: TEI (transmit-end interrupt), ERI (receive-error
interrupt), RXI (receive-data-full interrupt), and TXI (transmit-data-empty interrupt). Table 11-12
lists the interrupt sources and indicates their priority. These interrupts can be enabled and disabled
by the TIE, RIE, and TEIE bits in SCR. Each interrupt request is sent separately to the interrupt
controller.
The TXI interrupt is requested when the TDRE flag is set to 1 in SSR. The TEI interrupt is
requested when the TEND flag is set to 1 in SSR.
The RXI interrupt is requested when the RDRF flag is set to 1 in SSR. The ERI interrupt is
requested when the ORER, PER, or FER flag is set to 1 in SSR.
Table 11-12 SCI Interrupt Sources
Interrupt
ERI
RXI
TXI
TEI
Description
Receive error (ORER, FER, or PER)
Receive data register full (RDRF)
Transmit data register empty (TDRE)
Transmit end (TEND)
Priority
High
Low
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