HD6475348R Datasheet, PDF (191/487 Pages) Hitachi Semiconductor – Single-Chip Microcomputer

P7DDR can be written but not read. An attempt to read this register does not cause an error, but
all bits are read as 1, regardless of their true values.
At a reset and in the hardware standby mode, P7DDR is initialized to H'00, setting all pins for
input. P7DDR is not initialized in the software standby mode, so if a P7DDR bit is set to 1 when
the chip enters the software standby mode, the corresponding pin continues to output the value in
the port 7 data register.
A transition to the software standby mode initializes the on-chip supporting modules, so any pins
of port 7 that were being used by an on-chip timer when the transition occurs revert to general-
purpose input or output, controlled by P7DDR and P7DR.
2. Port 7 Data Register (P7DR)—H'FE8E
Bit
Initial value
Read/Write
7
P77
0
R/W
6
P76
0
R/W
5
P75
0
R/W
4
P74
0
R/W
3
P73
0
R/W
2
P72
0
R/W
1
P71
0
R/W
0
P70
0
R/W
P7DR is an 8-bit register containing the data for pins P77 to P70. When the CPU reads P7DR, for
output pins it reads the value in the P7DR latch, but for input pins, it obtains the pin status
directly.
9.8.3 Pin Functions
The pin functions of port 7 are the same in all MCU operating modes. As figure 9-19 indicated,
these pins are used for input and output of on-chip timer signals as well as for general-purpose
input and output. For some pins, two or more functions can be enabled simultaneously.
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