CHAPTER 14 PORT FUNCTION
User’s Manual U13850EJ4V0UM
384
14.2.3 Port 2
Port 2 is an 8-bit I/O port for which I/O settings can be controlled in 1-bit units.
A pull-up resistor can be connected in 1-bit units (software pull-up function).
P20, P21, P22, P24 and P25 are selectable as normal outputs or N-ch open-drain outputs.
When P26 and P27 are used as TI2 and TI3 pins, noise is eliminated from these pins by a digital noise eliminator.
Figure 14-13. 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 (in output mode) (n = 0 to 7)
0
Outputs 0
1
Outputs 1
Remark
In input mode:
When the P2 register is read, the pin levels at that time are read. Writing to P2 writes
the values to that register. This does not affect the input pins.
In output mode: When the P2 register is read, the P2 register’s values are read. Writing to P2 writes
the values to that register, and those values are immediately output.
Port 2 includes the following alternate functions. SDA1 and SCL1 are available only in the
µ
PD70303xAY and
70F303wAY.
Table 14-4. Port 2 Alternate Function Pins
Pin Name
Alternate Function
I/O
PULL
Note
Remark
Port 2
P20
SI2/SDA1
P21
SO2
P22
SCK2/SCL1
Selectable as N-ch open-drain output
P23
SI3/RXD1
−
P24
SO3/TXD1
P25
SCK3/ASCK1
Selectable as N-ch open-drain output
P26
TI2/TO2
P27
TI3/TO3
I/O
Yes
Digital noise elimination
Note
Software pull-up function
Содержание MPD703030A
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