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16.3.10 Port AH
Port AH is an 8-bit input/output port in which input or output can be specified in 1-bit units. After reset,
the port AH pins operate as an address bus to address external memories respectively peripherals.
Each port bit can be independently configured to port input, port output or peripheral function
This register can be read in 1-bit and 8-bit units.
7
PAH
PAH7
PAH6
Bit Position
Bit Name
PAHn
7 to 0
(n = 7 to 0)
Remark:
In Input Mode: When the PAH register is read, the pin levels at that time are read. Writing
In Output Mode:When the PAH register is read, the values of PAH are read. Writing to the
Besides functioning as a port, in control mode, it also can operate as an address bus.
Notes: 1. If using peripheral functions, the direction setting for the respective port bit is not forced
automatically. Port bit direction has to be programmed according to the peripheral function
requirement by setting the port mode register.
2. The reset value of register PAH is 00H. Due to the input mode of the port after reset, the
read input value is determined by the port pins.
(1)
Operation in control mode
Port
PAH7 to
Port AH
PAH0
Chapter 16 Port Functions
Figure 16-29: Port AH (PAH)
6
5
4
PAH5
PAH4
Input/output port
to the PAH register writes the values to that register. This does not affect
the input pins.
PAH register writes the values to that register and those values are
immediately output.
Alternate Pin Name
A23 to A16
Preliminary User's Manual U15839EE1V0UM00
3
2
1
PAH3
PAH2
PAH1
Function
Remarks
Address bus
Note 1
0
Address
At Reset
PAH0
FFFFF002H 00H
Block Type
.
Note 2
B
575
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