
R8C/38T-A Group
20. Serial Interface (UART2)
Under development Preliminary document
Specifications in this document are tentative and subject to change.
R01UH0241EJ0010 Rev.0.10
Page 450 of 730
Aug 05, 2011
Figure 20.28
Receive Operation Example during Multiprocessor Communication (with 8-Bit
Data/Multiprocessor Bit/One-Stop Bit)
20.3.4.3
RXD2 Digital Filter Select Function
Serial data
One frame
1
MP bit in
U2SMR5 register
MPIE bit in
U2SMR5 register
RI bit in
U2C1 register
Bits b0 to b7 in
U2RB register
Hardware
processing
Software
processing
(1) Detection of the MPRB bit
clears the MPIE bit to 0, and
requests a reception
complete interrupt.
(3) Reading bits b0 to b7 in
the U2RB register clears
the RI bit to 0.
(2) Read bits b0 to b7 in
the U2RB register.
(4) If data does not match own
station ID, set the MPIE bit
to 1 again.
(5) No reception complete interrupt
request is generated, and the
U2RB register retains state.
(1) When data does not match own station ID
(2) When data matches own station ID
Serial data
1
MP bit in
U2SMR5 register
MPIE bit in
U2SMR5 register
RI bit in
U2C1 register
Bits b0 to b7 in
U2RB register
Hardware
processing
Software
processing
D0
D1
D7
D0
D1
D7
Receive data (ID1)
MPRB
Start
bit
Stop
bit
Receive data (DATA1)
MPRB
Idle state
D0
D1
D7
D0
D1
D7
Receive data (ID2)
MPRB
Start
bit
Stop
bit
Receive data (DATA2)
MPRB
Idle state
ID1
ID2
DATA2
(1) Detection of the MPRB bit
clears the MPIE bit to 0, and
requests a reception complete
interrupt.
(3) Reading bits b0 to b7 in
the U2RB register clears
the RI bit to 0.
(2) Read bits b0 to b7 in
the U2RB register.
(4) If data matches
own station ID,
continue reception
without any setting
changes.
(5) A reception
complete
interrupt is
requested.
(6) Read bits b0 to b7 in
the U2RB register.
(7) Reading bits b0 to b7 in
the U2RB register clears
the RI bit to 0.
(8) Set the MPIE
bit to 1 again.
One frame