HD6475328-CP10 HITACHI [Hitachi Semiconductor], HD6475328-CP10 Datasheet - Page 167

• Manufacturer Part Number: HD6475328-CP10
• Description: original Hitachi CMOS microcomputer unit (MCU)
• Manufacturer: HITACHI [Hitachi Semiconductor]

Bit
Initial value
Read/Write
2. Port 2 Data Register (P2DR)—H'FF83
P2DR is an 8-bit register containing the data for pins P2
Bits 7 to 5 are reserved. They cannot be modified and are always read as “1.”
When the CPU reads P2DR, for output pins it reads the value in the P2DR latch, but for input
pins, it obtains the pin status directly.
9.3.3 Pin Functions in Each Mode
Port 2 has different functions in the expanded modes (modes 1, 2, 3, 4) and the single-chip mode
(mode 7). Separate descriptions are given below.
Figure 9-3 shows the pin functions in the expanded modes.
Pin Functions in Expanded Modes: In the expanded modes (modes 1, 2, 3, and 4), all pins of
P2DDR is automatically set to “1” for output. Port 2 outputs the bus control signals (AS, R/W,
DS, RD, WR).
—
—
7
1
Figure 9-3 Port 2 Pin Functions in Expanded Modes
Port
2
—
—
6
1
—
—
5
1
WR (output)
RD
DS
R/W (output)
AS
150
R/W
P2
4
0
(output)
(output)
(output)
4
4
to P2
R/W
P2
3
0
3
0
.
R/W
P2
2
0
2
R/W
P2
1
0
1
R/W
P2
0
0
0