CHAPTER 14 PORT FUNCTION
336
14.2.3 Port 2
Port 2 is an 8-bit I/O port for which I/O settings can be controlled bitwise.
A pull-up resistance can be connected bitwise (software pull-up function).
P21 and P22 are selectable as normal outputs or N-ch open drain outputs.
When P26 and P27 are used as TI2/TI3 pins, noise is eliminated from these pins by a digital noise elimination
circuit.
Figure 14-10. Format of Port 2 (P2)
After reset:
00H
R/W
Address: FFFFF004H
7
6
5
4
3
2
1
0
P2
P27
P26
P25
P24
P23
P22
P21
P20
P2n
Control of Output Data (during output mode)
0
Output “0”
1
Output “1”
Remark
During input mode
: When the P2 register is read, the pin levels at that time are read. Writing to P2
writes the current pin levels to that register. This does not affect the input pins.
During output mode : When the P2 register is read, the P2 register’s values are read. Writing to P2
writes values to that register, and those values are immediately output.
Port 2 includes the following alternate-function pins.
Pin Name
Alternate Function
I/O
PULL
Note
Remark
Port 2
P20
SI2
I/O
Yes
−
P21
SO2
Selectable as N-ch open drain output
P22
SCK2
P23
RXD1
−
P24
TXD1
P25
ASCK1
P26
TI2/TO2
Digital noise elimination
P27
TI3/TO3
Note
Software pull-up function
Summary of Contents for V850/SA1 mPD703015
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