Sci Interrupts - Renesas H8S Series Hardware Manual

14.4

SCI Interrupts

The SCI has four interrupt sources: the transmit-end interrupt (TEI) request, receive-error interrupt (ERI) request, receive-
data-full interrupt (RXI) request, and transmit-data-empty interrupt (TXI) request. Table 14-12 shows the interrupt sources
and their relative priorities. Individual interrupt sources can be enabled or disabled with the TIE, RIE, and TEIE bits in the
SCR. Each kind of interrupt request is sent to the interrupt controller independently.
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 DMAC or DTC to perform data transfer. The TDRE
flag is cleared to 0 automatically when data transfer is performed by the DMAC or DTC. The DMAC and DTC cannot be
activated by a TEI interrupt request.
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 or DTC to perform data
transfer. The RDRF flag is cleared to 0 automatically when data transfer is performed by the DMAC or DTC. The DMAC
and DTC cannot be activated by an ERI interrupt request.
Also note that the DMAC cannot be activated by an SCI channel 2 interrupt.
Rev.6.00 Oct.28.2004 page 512 of 1016
REJ09B0138-0600H