HD6433044 Datasheet, PDF (492/867 Pages) Hitachi Semiconductor – Hitachi Single-Chip Microcomputer

Figure 13-13 shows an example of SCI receive operation using a multiprocessor format.
MPIE
RDRF
Start
1
bit
Data (ID1)
0 D0 D1
Stop Start
MPB bit bit Data (data1)
D7 1 1 0 D0 D1
Stop
MPB bit
D7 0 1
1
Idle (mark)
state
RDR value
MPB detection
MPIE= 0
RXI request
(multiprocessor
interrupt)
ID1
RXI handler reads
Not own ID, so
RDR data and clears MPIE bit is set
RDRF flag to 0
to 1 again
No RXI request,
RDR not updated
a. Own ID does not match data
MPIE
RDRF
Start
1
bit
Data (ID2)
0 D0 D1
Stop Start
MPB bit bit Data (data2)
D7 1 1 0 D0 D1
Stop
MPB bit
D7 0 1
1
Idle (mark)
state
RDR value
MPB detection
MPIE= 0
RXI request
(multiprocessor
interrupt)
ID2
Data 2
RXI interrupt handler Own ID, so receiving MPIE bit is set
reads RDR data and continues, with data to 1 again
clears RDRF flag to 0 received by RXI
interrupt handler
b. Own ID matches data
Figure 13-13 Example of SCI Receive Operation (8-Bit Data with Multiprocessor Bit and
One Stop Bit)
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