99
Clock asynchronous serial I/O (UART) mode
M
i
t
s
u
M
S
b
i
s
3
M
h
0
I
C
i
m
2
R
i
1
O
c
r
8
C
o
c
o
G
M
m
p
r
P
u
t
u
T
e
r
p
R
s
o
U
S
I
N
G
L
E
-
C
H
I
P
1
6
-
B
I
T
C
M
O
O
E
Table 27 lists the functions of the input/output pins during UART mode. Note that for a period from when
the UARTi operation mode is selected to when transfer starts, the TxDi pin outputs a “H”. (If the N-
channel open-drain is selected, this pin is in floating state.)
Table 27. Input/output pin functions in UART mode (i=0,1)
Figure 84. UARTi transmit/receive mode register in UART mode
Pin name
Function
Method of selection
TxDi
(P4
4
, P7
4
)
RxDi
(P4
5
, P7
5
)
CLKi
(P4
6
, P7
6
)
Serial data output
Serial data input
Programmable I/O port
Transfer clock input
Programmable I/O port
Internal/external clock select bit (bit 3 at address 03A0
16
, 03A8
16
) = “0”
Internal/external clock select bit (bit 3 at address 03A0
16
, 03A8
16
) = “1”
Port P4
5
, P7
5
direction register (bits 5 at address 03EA
16
and 03EF
16
)= “0”
(Can be used as an input port when performing transmission only)
CTS/RTS disable bit (bit 4 at address 03A4
16
, 03AC
16
) =“0”
CTS/RTS function select bit (bit 2 at address 03A4
16
, 03AC
16
) = “0”
Port P4
7
, P7
7
direction register (bits 7 at address 03EA
16
and 03EF
16
) = “0”
CTS/RTS disable bit (bit 4 at address 03A4
16
, 03AC
16
)
= “0”
CTS/RTS function select bit (bit 2 at address 03A4
16
, 03AC
16
) = “1”
CTS/RTS disable bit (bit 4 at address 03A4
16
, 03AC
16
) = “1”
CTS input
RTS output
CTSi/RTSi
(P4
7
, P7
7
)
(Outputs dummy data when performing reception only)
Symbol
UiMR (i=0,1)
Address
03A0
16
, 03A8
16
When reset
00
16
CKDIR
UARTi transmit/receive mode register
Internal/external clock
select bit
Stop bit length select bit
STPS
PRY
PRYE
SLEP
0 : Internal clock
1 : External clock
0 : One stop bit
1 : Two stop bits
Valid when bit 6 = “1”
0 : Odd parity
1 : Even parity
Bit name
Function
Bit symbol
W
R
b7
b6
b5
b4
b3
b2
b1
b0
SMD0
SMD1
SMD2
Serial I/O mode select bit
b2 b1 b0
1 0 0 : Transfer data 7 bits long
1 0 1 : Transfer data 8 bits long
1 1 0 : Transfer data 9 bits long
0 : Parity disabled
1 : Parity enabled
0 : Sleep mode deselected
1 : Sleep mode selected
Odd/even parity select bit
Parity enable bit
Sleep select bit