76

µ
PD78214 Sub-Series
5.5.1 Hardware Configuration

Fig. 5-21 shows the hardware configuration of port 4.

Fig. 5-21 Block Diagram of Port 4

5.5.2 Setting the I/O Mode and Control Mode

The memory expansion mode register (MM, see Fig 13-1) specifies the operating mode of port 4, as listed in Table

5-5.

Table 5-5 Port 4 Operating Modes

1
1
1
0
0
0
1
×
MM2
0
0
1
×
MM1
0
1
1
×
MM0
EA pin
MM register bit
Operation mode
Input port
Output port
Address/data bus
(AD0-AD7)

For the

µ

PD78213, port 4 functions only as the address/data bus (AD0 through AD7).

Internal data bus
WRPUO Pull-up resistor option register
PUO4
WRP4n
RDP4n
RDPUO
Output latch
P4n
n = 0 to 7
VDD
MM0-MM2 EA
Internal address bus
I/O control circuit
P4n