NEC PD78P214 Manuale Utente

PD78214 Sub-Series

Fig. 5-37 Block Diagram of P67 (Port 6)

5.7.2 Setting the I/O Mode and Control Mode

The port 6 mode register (PM6) can put port 6 in either the input or output mode as shown in Fig. 5-38. Table 5-
8 lists the operations needed to make port 6 function as control pins.

P66 and P67 can always receive analog signals.

The ADM of the A/D converter specifies the mode of the A/D converter operation. (See Chapter 8.) To use port
6 as AN6 and AN7, however, it is necessary to specify the input mode using the port 6 mode register (PM6) and
disconnection of a pull-up resistor using the PUO6 bit (= 0) of the pull-up-resistor-option register (PUO).

For the

µPD78213, P64 and P65 function only as output pins for RD and WR, respectively.

Table 5-8 Port 6 Control Pin Functions and the Required Operations

P60

P61

P62

P63

P64

P65

P66

P67

I/O

Function

A16

A17

A18

A19

WAIT

REFRQ

Operation needed to make port 6 function as control pins

Output

Input

Output

Set the MM6 bit of the MM register to 1.

For the

PD78213, no special operation is needed. For the other models, specify

the memory expansion mode by the MM2 through MM0 bits of the MM register.

Specify insertion of external wait using the PW register or the PWn1 and PWn0

bits (n = 2 or 3) of the MM register or by putting P66 in the input mode.

Set the RFEN bit of the RFM register to 1.

Internal bus

OUT

A/D converter

P67

PUO

Pull-up resistor option register

PUO6

Port 6 mode register

PM67

Output latch

P67

Selector

Refresh signal

Refresh mode