HD6433308 Datasheet, PDF (122/349 Pages) Hitachi Semiconductor – Hitachi Single-Chip MicroComputer

Pin P86: This pin has the same functions in all modes. It can be used for general-purpose input or
output, for serial clock input or output (CSCK), or for IRQ5 input. When this pin is used for IRQ5
input, P86DDR should normally be cleared to "0," so that the value in P8DR will not generate
interrupts.
When used for CSCK input or output, this pin is unaffected by the values in P8DDR and P8DR,
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." For CSCK usage, the MOS pull-up should be turned off.
Reset: A reset clears bits P86DDR to P81DDR to “0” and clears the DPME bit, serial control bits,
and interrupt enable bits to “0,” making P86 to P81 into input port pins with the MOS pull-ups off.
In the expanded modes (modes 1 and 2), P80DDR is initialized to “1” and the P80 pin is used for E
clock output. In the single-chip mode (mode 3), P80DDR is initialized to “0” and the P80 pin is
used for port input.
Hardware Standby Mode: All pins are placed in the high-impedance state with the MOS pull-ups
off.
Software Standby Mode: In the software standby mode, the serial control register is initialized,
but the DPME bit, the interrupt enable register, P8DDR, and P8DR remain in their previous states.
Pins that were being used for serial communication revert to general-purpose input or output,
depending on the value in P8DDR. Other pins remain in their previous state. Output pins output
the values in P8DR. E clock output is Low.
Figures 5-14 to 5-19 show schematic diagrams of port 8.
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