SH7727 Datasheet, PDF (672/1109 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7700 Series

Section 19 Serial Communication Interface with FIFO (SCIF)
19.4 SCIF Interrupts
The SCIF has four interrupt sources: transmit-FIFO-data-empty (TXI), receive-error (ERI),
receive-data-full (RXI), and break (BRI).
Table 19.9 shows the interrupt sources and their order of priority. The interrupt sources are
enabled or disabled by means of the TIE and RIE bits in SCSCR2. A separate interrupt request is
sent to the interrupt controller for each of these interrupt sources.
When the TDFE flag in the serial status register 2 (SCSSR2) is set to 1, a TXI interrupt request is
generated. The DMAC can be activated and data transfer performed when this interrupt is
generated. The TDFE flag is cleared when data exceeding the transmit trigger number is written
to transmit FIFO data register 2 (SCFTDR2) by the DMAC, 1 is read from TDFE, and then 0 is
written to TDFE.
When the RDF flag in SCSSR2 is set to 1, an RXI interrupt request is generated. The DMAC can
be activated and data transfer performed when the RDF flag in SCSSR is set to 1. The RDF flag is
cleared when receive data is read from receive FIFO data register 2 (SCFRDR2) by the DMAC
until the quantity of receive data in SCFRDR2 is less than the receive trigger number, 1 is read
from RDF, and then 0 is written to RDF.
When the ER flag in SCSSR2 is set to 1, an ERI interrupt request is generated.
When the BRK flag in SCSSR2 is set to 1, a BRI interrupt request is generated.
The TXI interrupt indicates that transmit data can be written, and the RXI interrupt indicates that
there is receive data in SCFRDR2.
Table 19.9 SCIF Interrupt Sources
Interrupt
Source
ERI
RXI
BRI
TXI
Description
DMAC
Activation
Interrupt initiated by receive error flag (ER)
Impossible
Interrupt initiated by receive data FIFO full flag
(RDF) or data ready flag (DR)
Possible
(RDF only)
Interrupt initiated by break flag (BRK)
Impossible
Interrupt initiated by transmit FIFO data empty flag Possible
(TDFE)
Priority on
Reset Release
High
Low
See section 4, Exception Processing, for priorities and the relationship with non-SCIF interrupts.
Rev. 5.00 Dec 12, 2005 page 600 of 1034
REJ09B0254-0500