HD6433640 HITACHI [Hitachi Semiconductor], HD6433640 Datasheet - Page 322

• Manufacturer Part Number: HD6433640
• Description: H8/3644 Series Hardware Manual
• Manufacturer: HITACHI [Hitachi Semiconductor]

Interrupts and Continuous Transmission/Reception: SCI3 can carry out continuous reception
using RXI and continuous transmission using TXI. These interrupts are shown in table 10.13.
Table 10.13 Transmit/Receive Interrupts
Interrupt
RXI
TXI
TEI
316
Flags
RDRF
RIE
TDRE
TIE
TEND
TEIE
Interrupt Request Conditions
When serial reception is performed
normally and receive data is
transferred from RSR to RDR, bit
RDRF is set to 1, and if bit RIE is set
to 1 at this time, RXI is enabled and
an interrupt is requested. (See figure
10.7 (a).)
When TSR is found to be empty (on
completion of the previous
transmission) and the transmit data
placed in TDR is transferred to TSR,
bit TDRE is set to 1. If bit TIE is set to
1 at this time, TXI is enabled and an
interrupt is requested. (See figure
10.7 (b).)
When the last bit of the character in
TSR is transmitted, if bit TDRE is set
to 1, bit TEND is set to 1. If bit TEIE is
set to 1 at this time, TEI is enabled
and an interrupt is requested. (See
figure 10.7 (c).)
Notes
The RXI interrupt routine reads
the receive data transferred to
RDR and clears bit RDRF to 0.
Continuous reception can be
performed by repeating the above
operations until reception of the
next RSR data is completed.
The TXI interrupt routine writes
the next transmit data to TDR and
clears bit TDRE to 0. Continuous
transmission can be performed by
repeating the above operations
until the data transferred to TSR
has been transmitted.
TEI indicates that the next
transmit data has not been written
to TDR when the last bit of the
transmit character in TSR is sent.