Multiprocessor Serial Data Reception; Figure 14.12 Example Of Sci Operation In Reception (Example With 8-Bit Data, Multiprocessor Bit, One Stop Bit) - Renesas H8S Series Hardware Manual

Section 14 Serial Communication Interface (SCI)
14.5.2

Multiprocessor Serial Data Reception

Figure 14.13 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
14.12 shows an example of SCI operation for multiprocessor format reception.
Start
1 bit
0
MPIE
RDRF
RDR
value
MPIE = 0
Start
1
bit
0
MPIE
RDRF
RDR
value
MPIE = 0
Figure 14.12 Example of SCI Operation in Reception
(Example with 8-Bit Data, Multiprocessor Bit, One Stop Bit)
Rev. 6.00 Mar 15, 2006 page 352 of 570
REJ09B0211-0600
Data (ID1)
MPB
D0 D1 D7 1
RXI interrupt
RDR data read
request
and RDRF flag
(multiprocessor
cleared to 0 in
interrupt)
RXI interrupt
generated
service routine
(a) Data does not match station's ID
Data (ID2)
MPB
D0 D1 D7 1
ID1
RXI interrupt RDR data read and
request RDRF flag cleared
(multiprocessor to 0 in RXI interrupt
interrupt) service routine
generated
(b) Data matches station's ID
Stop Start Data (Data1)
bit bit
1 0 D0 D1
If not this station's ID,
MPIE bit is set to 1
again
Stop Start Data (Data2)
bit bit
1 0 D0 D1
Matches this station's ID,
so reception continues, and
data is received in RXI
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 Data2
MPIE bit set to 1
again