HD6473258F10V Datasheet, PDF (115/301 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

P7DR is an 8-bit register containing output data for pins P77 to P70, and controlling their input pull-
ups. When the CPU reads P7DR, for output pins (P7DDR = 1) it reads the value in the P7DR latch,
but for input pins (P7DDR = 0), it obtains the logic level directly from the pin, bypassing the P7DR
latch. This also applies to pins used for control signal input or output.
MOS Pull-Ups: Are available for input pins, including pins used for input of the IS and WAIT
signals. Software can turn the MOS pull-up on by writing a 1 in P7DR, and turn it off by writing a
0. The pull-ups are automatically turned off for output pins.
Pin P70: Can be used for general-purpose input or output, or input of the input strobe (IS) parallel
handshake signal. When P70 is used for IS input, P70DDR should be cleared to 0, so that output
from P7DR will not cause unintended strobes. If input pull-up is not desired, P70DR should also be
cleared to 0.
Pins P71 and P72: In modes 1 and 2 (expanded modes), these pins can be used for general-purpose
input or output.
In mode 3 (single-chip mode), these pins can be used for general-purpose input or output or for
output of the OS and BUSY parallel handshake signals, depending on the OSE and BSE bits in the
handshake control/status register. See section 6, Parallel Handshaking Interface, for further
information. Pins used for parallel handshaking output are unaffected by the values in P7DDR and
P7DR, and their MOS pull-ups are automatically turned off.
Pin P73: In modes 1 and 2 (expanded modes) P73 is used for IOS output if P73DDR is set to 1, and
for general-purpose input if P73DDR is cleared 0. It cannot be used for general-purpose output.
In mode 3 (single-chip mode), pin P73 can be used for general-purpose input or output.
Pins P74, P75, and P76: In modes 1 and 2 (expanded modes), these pins are used for output of the
AS, RD, and WR bus control signals. They are unaffected by the values in P7DDR and P7DR, and
their MOS pull-ups are automatically turned off.
In mode 3 (single-chip mode), these pins can be used for general-purpose input or output.
Pin P77: In modes 1 and 2, this pin is used for input of the WAIT bus control signal. It is unaffected
by the values in P7DDR and P7DR, except that software can turn on its MOS pull-up by clearing
its data direction bit to 0 and setting its data bit to 1.
106