Unde
deeopmen
Clock asynchronous serial I/O (UART) mode
Preliminary Specifications REV.E
Specifications in this manual are tentative and subject to change.
Mitsubishi microcomputers
M30220 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
112
Figure 1.15.21. Typical transmit/receive timing in UART mode (compliant with the SIM interface)
Transmit enable
bit(TE)
Transmit buffer
empty flag(TI)
Transmit register
empty flag (TXEPT)
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
P
Start
bit
Parity
bit
The above timing applies to the following settings :
Parity is enabled.
One stop bit.
Transmit interrupt cause select bit = “1”.
“0”
“1”
“0”
“1”
“0”
“1”
Tc = 16 (n + 1) / fi
fi : frequency of BRG2 count source (f
1
, f
8
, f
32
)
n : value set to BRG2
Transmit interrupt
request bit (IR)
“0”
“1”
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
P
Shown in ( ) are bit symbols.
Tc
Transfer clock
SP
Stop
bit
Data is set in UART2 transmit buffer register
SP
A “L” level returns from TxD
due to
the occurrence of a parity error.
The level is detected by the
interrupt routine.
The level is
detected by the
interrupt routine.
Receive enable
bit (RE)
Receive complete
flag (RI)
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
P
Start
bit
Parity
bit
RxD
2
The above timing applies to the following settings :
Parity is enabled.
One stop bit.
Transmit interrupt cause select bit = “0”.
“0”
“1”
“0”
“1”
Tc = 16 (n + 1) / fi
fi : frequency of BRG2 count source (f
1
, f
8
, f
32
)
n : value set to BRG2
Receive interrupt
request bit (IR)
“0”
“1”
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
P
SP
Shown in ( ) are bit symbols.
Tc
Transfer clock
SP
Stop
bit
A “L” level returns from TxD
2
due to
the occurrence of a parity error.
TxD
2
Read to receive buffer
Read to receive buffer
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
P
Signal conductor level
(Note 2)
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
Signal conductor level
(Note 2)
Note 1 : The transmit is started with overflow timing of BRG after having written in a value at the transmit buffer in the above timing.
Note 2 : Equal in waveform because TxD
2
and RxD
2
are connected.
Transferred from UART2 transmit buffer register to UART2 transmit register
Cleared to “0” when interrupt request is accepted, or cleared by software
Cleared to “0” when interrupt request is accepted, or cleared by software
Note 1