HD6473847RHV Datasheet, PDF (329/546 Pages) Renesas Technology Corp – Renesas 8-Bit Single-Chip Microcomputer H8 Family / H8/300L Super Low Power Series

Section 10 Serial Communication Interface 3 (SCI3)
10.6 Interrupts
The SCI3 creates the following six interrupt requests: transmission end, transmit data empty,
receive data full, and receive errors (overrun error, framing error, and parity error). Table 10.11
shows the interrupt sources.
Table 10.11 SCI3 Interrupt Requests
Interrupt Requests
Receive Data Full
Transmit Data Empty
Transmission End
Receive Error
Abbreviation
RXI
TXI
TEI
ERI
Interrupt Sources
Setting RDRF in SSR
Setting TDRE in SSR
Setting TEND in SSR
Setting OER, FER, or PER in SSR
Enable Bit
RIE
TIE
TEIE
RIE
Each interrupt request can be enabled or disabled by means of bits TIE, RIE and TEIE in SCR3.
When bit TDRE is set to 1 in SSR, a TXI interrupt is requested. When bit TEND is set to 1 in
SSR, a TEI interrupt is requested. These two interrupts are generated during transmission.
The initial value of the TDRE flag in SSR is 1. Thus, when the TIE bit in SCR3 is set to 1 before
transferring the transmit data to TDR, a TXI interrupt request is generated even if the transmit data
is not ready. The initial value of the TEND flag in SSR is 1. Thus, when the TEIE bit in SCR3 is
set to 1 before transferring the transmit data to TDR, a TEI interrupt request is generated even if
the transmit data has not been sent. It is possible to make use of the most of these interrupt
requests efficiently by transferring the transmit data to TDR in the interrupt routine. To prevent the
generation of these interrupt requests (TXI and TEI), set the enable bits (TIE and TEIE) that
correspond to these interrupt requests to 1, after transferring the transmit data to TDR.
When bit RDRF is set to 1 in SSR, an RXI interrupt is requested, and if any of bits OER, PER, and
FER is set to 1, an ERI interrupt is requested. These two interrupt requests are generated during
reception.
For further details, see section 3, Exception Handling.
The SCI3 can carry out continuous reception using RXI and continuous transmission using TXI.
These interrupts are shown in table 10.12.
Rev. 7.00 Mar. 08, 2010 Page 297 of 510
REJ09B0024-0700