Section 15 Serial Communication Interface (SCI)
15.5.2
Multiprocessor Serial Data Reception
Figure 15.13 shows a sample flowchart for multiprocessor serial data reception. If the MPIE bit in
SCR is set to 1, data is skipped until data with a 1 multiprocessor bit is sent. On receiving data
with a 1 multiprocessor bit, the receive data is transferred to RDR. An RXI interrupt request is
generated at this time. All other SCI operations are the same as in asynchronous mode. Figure
15.12 shows an example of SCI operation for multiprocessor format reception.
Start
1
bit
0
MPIE
RDRF
RDR
value
Start
1
bit
0
MPIE
RDRF
RDR
value
Figure 15.12 Example of SCI Operation in Reception
(Example with 8-Bit Data, Multiprocessor Bit, One Stop Bit)
Rev. 1.00 Apr. 28, 2008 Page 438 of 994
REJ09B0452-0100
Data (ID1)
MPB
D0
D1
D7
1
MPIE = 0
RXI interrupt
request
(multiprocessor
interrupt)
generated
(a) Data does not match station's ID
Data (ID2)
MPB
D0
D1
D7
1
ID1
MPIE = 0
RXI interrupt
request
(multiprocessor
interrupt)
generated
(b) Data matches station's ID
Stop
Start
Data (Data 1)
bit
bit
1
0
D0
D1
RDR data read
If not this station's ID,
and RDRF flag
MPIE bit is set to 1
cleared to 0 in
again
RXI interrupt
service routine
Stop
Start
Data (Data 2)
bit
bit
1
0
D0
D1
RDR data read and
Matches this station's ID,
RDRF flag cleared
so reception continues, and
to 0 in RXI interrupt
data is received in RXI
service routine
interrupt service routine
Stop
MPB
bit
1
D7
0
1
Idle state
(mark state)
ID1
RXI interrupt request is
not generated, and RDR
retains its state
Stop
1
MPB
bit
D7
0
1
Idle state
(mark state)
ID2
Data 2
MPIE bit set to 1
again