MPD78C10AL datasheet(89/373 Pages) NEC

89 / 373 page

CHAPTER 4

PORT FUNCTIONS

4.5 Port F (PF7 to PF0)

µPD78C18/78C14/78C14A/78C12A/78C11A/78CP18/78CP14

Port F is an 8-bit special input/output port; in addition to functioning as a general-purpose input/output port (port

mode), this port also functions as an address bus.

Port/expansion mode can be specified in steps for PF7 to PF0 by means of the memory mapping register (see

11.1.1 Memory mapping register (MM)).

(1) Port mode

Like port A, port F is an 8-bit input/output port with input/output buffer and output latch functions (see Figure

4-1. Port A).

Port F can be set bit-wise as an input or output port by means of the mode F register (MF). When set to

input, the pins become high-impedance.

When the corresponding bit of the mode F register is set (1), a port F pin functions as an input port pin, and

when reset (0), as an output port pin.

When RESET is input or the hardware STOP mode is set all bits of the mode F register are set.

Figure 4-10. Mode F Register Format

MF7

MF6

MF5

MF4

MF3

MF2

MF1

MF0

PF7

PF6

PF5

PF4

PF3

PF2

PF1

PF0

PFn = Output port

PFn = Input port

(n = 0 – 7)

As with port A, direct bit setting/resetting and bit testing of port F output latch contents is possible by an

arithmetic or logical operation instruction without the use of an accumulator. Data transfer to/from an

accumulator is also possible.

MPD78C10AL Datasheet(PDF) 89 Page - NEC