UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 166

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

5.6.2 Input/Output Mode / Control Mode Setting
21-1) as shown in Table 5-7.
126
The port 4 input/output mode is set for each pin by means of the port 4 mode register (PM4) as shown in Figure 5-39.
When port 4 is used as the address/data bus, it is set by means of the memory extension mode register (MM: See Figure
In the PD784021, port 4 only operates as the address/data bus (AD0 to AD7).
PM4
PM47
7
PM46
6
PM45
MM3
5
0
0
0
0
0
0
1
1
Figure 5-39 Port 4 Mode Register (PM4) Format
PM44
MM2
4
0
0
1
1
1
1
0
0
MM Bits
Table 5-7 Port 4 Operating Modes
PM43
CHAPTER 5 PORT FUNCTIONS
3
MM1
0
1
0
0
1
1
0
0
PM42
2
MM0
0
1
0
1
0
1
0
1
PM41
1
Port
Address/data bus (AD0 to AD7)
PM40
0
Operating Mode
PM4n
0FF24H
Address
0
1
P4n Pin Input/Output Mode
Specification (n = 0 to 7)
Output mode (output buffer on)
Intput mode (output buffer off)
On Reset
FFH
R/W
R/W