
24. Programmable I/O Ports
Figure 24.8
PS2 Register, PS3 Register
b7
0
b6 b5 b4
b1
b2
b3
Symbol
PS2
Address
03B4h
After Reset
00X0 0000b
b0
Function
Bit Symbol
Bit Name
RW
(b5)
RW
Reserved bits
(b7-b6)
Function Select Register A2
Port P8_1
output function select bit
PS2_1
RW
Port P8_2
output function select bit
RW
PS2_2
0: I/O port
1: Select by the PSL2_0 bit
Port P8_0
output function select bit
PS2_0
RW
0: I/O port
1: Select by the PSL2_1 bit
0: I/O port
1: Select by the PSL2_2 bit
Nothing is assigned. If necessary, set to 0.
When read, the content is undefined
Set to 0
b7 b6 b5 b4
b1
b2
b3
Symbol
PS3
Address
03B5h
After Reset
00h
b0
Function
Bit Symbol
Bit Name
RW
PS3_5
PS3_7
Port P9_3
output function select bit
Port P9_7
output function select bit
RW
PS3_4
RW
PS3_3
Port P9_5
output function select bit
Port P9_6
output function select bit
PS3_6
Function Select Register A3(1)
Port P9_4
output function select bit
Port P9_1
output function select bit
PS3_1
RW
Port P9_2
output function select bit
RW
PS3_2
0: I/O port
1: Select by the PSL3_0 bit
Port P9_0
output function select bit
PS3_0
RW
0: I/O port
1: Select by the PSL3_1 bit
0: I/O port
1: Select by the PSL3_2 bit
0: I/O port
1: RTS3 output
0: I/O port
1: RTS4 output
0: I/O port
1: CLK4 output
0: I/O port
1: Select by the PSC3_6 bit
0: I/O port
1: Select by the PSL3_7 bit
NOTE:
1. Set the PS3 register immediately after the PRC2 bit in the PRCR register is set to 1 (write enable). Do not generate an interrupt
or a DMA or DMACII transfer between the instruction to set the PRC2 bit to 1 and the instruction to set the PS3 register.
RW
Reserved bits
(b4-b3)
Set to 0