H8SSLASH2225 datasheet(708/1071 Pages) RENESAS

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Section 15 Serial Communication Interface (SCI)

Rev. 5.00 Aug 08, 2006 page 622 of 982

REJ09B0054-0500

15.9

Interrupt Sources

15.9.1

Interrupts in Normal Serial Communication Interface Mode

Table 15.12 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 can activate the DTC to perform data transfer. The TDRE flag is cleared to 0

automatically when data is transferred by the DMAC*1 or the DTC*2.

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 request can activate the DMAC*1 or the DTC*2 to transfer data. The RDRF flag

is cleared to 0 automatically when data is transferred by the DMAC*1 or the DTC*2.

A TEI interrupt is requested when the TEND flag is set to 1 and 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, if the TDRE and TEND flags are cleared simultaneously by the TXI

interrupt routine, the SCI cannot branch to the TEI interrupt routine later.

Notes: 1. Supported only by the H8S/2239 Group.

2. The flag is cleared only when DISEL in DTC is 0 with the transfer counter not being 0.

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