HD6473258P10V Datasheet, PDF (98/301 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

Port 4 Data Register (P4DR)—H’FFB7
Bit
Initial value
Read/Write
7
6
5
4
3
2
1
0
P47
P46
P45
P44
P43
P42
P41
P40
0
0
0
0
0
0
0
0
R/W R/W R/W R/W R/W R/W R/W R/W
P4DR is an 8-bit register containing output data for pins P47 to P40, and controlling their input pull-
ups. When the CPU reads P4DR, for output pins (P4DDR = 1) it reads the value in the P4DR latch,
but for input pins (P4DDR = 0), it obtains the logic level directly from the pin, bypassing the P4DR
latch. This also applies to pins used for timer or clock input or output.
MOS Pull-Ups: Are available for input pins, including timer input pins, in all modes. Software can
turn the MOS pull-up on by writing a 1 in P4DR, and turn it off by writing a 0. The pull-ups are
automatically turned off for output pins.
Pins P40, P42, P43, and P45: As indicated in table 5-8, these pins can be used for general-purpose
input or output, or input of 8-bit timer clock and reset signals. When a pin is used for timer signal
input, its P4DDR bit should normally be cleared to 0; otherwise the timer will receive the value in
P4DR. If input pull-up is not desired, the P4DR bit should also be cleared to 0.
Pins P41 and P44: As indicated in table 5-8, these pins can be used for general-purpose input or
output, or for 8-bit timer output. Pins used for timer output are unaffected by the values in P4DDR
and P4DR, and their MOS pull-ups are automatically turned off.
Pin P46: In modes 1 and 2 (expanded modes) this pin is used for system clock (Ø) output,
regardless of the value in P46DDR. The MOS pull-up is automatically turned off.
In mode 3 (single-chip mode) this pin is used for general-purpose input if P46DDR is cleared to 0,
or system clock output if P46DDR is set to 1. It cannot be used for general-purpose output.
Pin P47: In modes 1 and 2 (expanded modes) pin P47 is used for E clock output if P47DDR is set to
1, and for general-purpose input if P47DDR is cleared to 0. It cannot be used for general-purpose
output.
In mode 3 (single-chip mode) pin P47 is used for general-purpose input/output.
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