Toshiba H1 Series Data Book page 133

3.7.7 Port 9 (P90 to P92, P96, P97)
P90 to P92 are 3-bit general-purpose I/O port. I/O can be set on bit basis using the
control register. Resetting sets P90 to P92 to input port and all bits of output latch to"1".
P96 to P97 are 2-bit general-purpose input port.
Writing "1" in the corresponding bit of P9FC enables the respective functions.
Resetting resets the P9FC to "0", and sets all bits to input ports.
(1) Port 90 (TXD0), Port 91 (RXD0), Port 92 (SCLK0,
Port 90 to 92 are general-purpose I/O port. They are also used either SIO0. Each pin
is below.
TXD0 output
SIO mode
(SIO0 module)
P90 TXD0
(Data output)
P91 RXD0
(Data input)
P92 SCLK0
(Clock input or
output)
Reset
Direction
control
(on bit basis)
P9CR write
Function
control
(on bit basis)
P9FC write
S
A S
Output latch
Selector
P9 write
B
S
B
Selector
P9 read
A
Figure 3.7.14 P90
92CZ26A-130
CTS )
0
UART, IrDA mode
(SIO0 module)
TXD0
(Data output)
RXD0
(Data input)
CTS 0
(Clear to send)
Open-drain enable
P9FC2<P90F2>
TMP92CZ26A
P90 (TXD0)