
94
Serial I/O
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
Figure 79. UARTi transmit/receive mode register in clock synchronous serial I/O mode (i=0,1)
Table 25 lists the functions of the input/output pins during clock synchronous serial I/O 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 25. Input/output pin functions in clock synchronous serial I/O mode (i=0,1)
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
STPS
PRY
PRYE
SLEP
0 : Internal clock
1 : External clock
Bit name
Function
Bit symbol
W
R
b7
0
b6
b5
b4
b3
b2
0
b1
0 1
b0
0 (Must always be "0" in clock synchronous serial I/O mode)
SMD0
SMD1
SMD2
Serial I/O mode select bit
0 0 1 : Clock synchronous serial
I/O mode
b2 b1 b0
Invalid in clock synchronous serial I/O mode
Pin name
Function
Method of selection
TxDi
(P4
4
, P7
4
)
RxDi
(P4
5
, P7
5
)
Serial data output
Serial data input
Transfer clock output
Transfer clock input
Programmable I/O port
(Outputs dummy data when performing reception only)
CLKi
(P4
6
, P7
6
)
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
6
, P7
6
direction register (bits 6 at address 03EA
16
and 03EF
16
) = “0”
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 address 03EA
16
and 03EF16
) = “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
)