Serial I/O (Special Modes)
181
Mitsubishi microcomputers
M16C / 62P Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
development
Preliminary Specifications Rev.1.0
Specifications in this manual are tentative and subject to change.
Figure 1.20.10. Transmit and Receive Timing in SIM Mode
Transfer clock
An “L” level is output from TxD
2
due to
the occurrence of a parity error
Read the U2RB register
Cleared to “0” when interrupt request is accepted, or cleared to “0” in a program
U2C1 register
TE bit
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
P
“0”
“1”
“0”
“1”
“0”
“1”
“0”
“1”
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
PSP
Tc
SP
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
P
TxD
2
“0”
“1”
“0”
“1”
“0”
“1”
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
P
SP
Tc
SP
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
P
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
P
SP
SP
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
P
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
P
SP
SP
TxD
2
RxD
2
pin level
U2C1 register
TI bit
Parity error signal sent
back from receiver
(Note)
U2C0 register
TXEPT bit
S2TIC register
IR bit
Start
bit
Parity
bit
Stop
bit
Write data to U2TB register
Transferred from U2TB register to UART2 transmit register
An “L” level returns due to the
occurrence of a parity error.
The level is
detected by the
interrupt routine.
The level is detected by the
interrupt routine.
The IR bit is set to “1” at the
falling edge of transfer clock
Note : Because TxD
2
and RxD
2
are connected, this is composite waveform consisting of the transmitter's transmit waveform and the
parity error signal received.
Note : Because TxD
2
and RxD
2
are connected, this is composite waveform consisting of the TxD
2
output and the parity error signal
sent back from receiver.
Tc = 16 (n + 1) / fi or 16 (n + 1) / f
EXT
fi : frequency of U2BRG count source (f
1SIO
, f
2SIO
, f
8SIO
, f
32SIO
)
f
EXT
: frequency of U2BRG count source (external clock)
n : value set to U2BRG
The above timing diagram applies to the case where data is received in
direct format.
U2MR register PRY bit = 1 (even)
U2C0 register UFORM bit = 0 (LSB first)
U2C1 register U2LCH bit = 0 (no reverse)
Tc = 16 (n + 1) / fi or 16 (n + 1) / f
EXT
fi : frequency of U2BRG count source (f
1SIO
, f
2SIO
, f
8SIO
, f
32SIO
)
f
EXT
: frequency of U2BRG count source (external clock)
n : value set to U2BRG
The above timing diagram applies to the case where data is transferred in
the direct format.
U2MR register PRY bit = 1 (even)
U2C0 register UFORM bit = 0 (LSB first)
U2C1 register U2LCH bit = 0 (no reverse)
Start
bit
Parity
bit
Stop
bit
Cleared to “0” when interrupt request is accepted, or cleared to “0” in a program
Read the U2RB register
(1) Transmission
Transfer clock
U2C1 register
RE bit
RxD
2
pin level
Transmitter's
transmit waveform
(Note)
U2C0 register
RI bit
S2RIC register
IR bit
(1) Reception