w78le58 Winbond Electronics Corp America, w78le58 Datasheet - Page 10

• Manufacturer Part Number: w78le58
• Description: 8-bit Microcontroller
• Manufacturer: Winbond Electronics Corp America

Port 4 Base Address Registers
P40AH, P40AL:
The Base address register for comparator of P4.0. P40AH contains the high-order byte of address,
P40AL contains the low-order byte of address.
P41AH, P41AL:
The Base address register for comparator of P4.1. P41AH contains the high-order byte of address,
P41AL contains the low-order byte of address.
P42AH, P42AL:
The Base address register for comparator of P4.2. P42AH contains the high-order byte of address,
P42AL contains the low-order byte of address.
P43AH, P43AL:
The Base address register for comparator of P4.3. P43AH contains the high-order byte of address,
P43AL contains the low-order byte of address.
P4 (D8H)
Here is an example to program the P4.0 as a write strobe signal at the I/O port address
1234H 1237H and positive polarity, and P4.1 P4.3 are used as general I/O ports.
MOV P40AH,#12H
MOV P40AL,#34H
MOV P4CONA,#00001010B
MOV P4CONB,#00H
MOV P2ECON,#10H
MOV CHPENR,#00H
Then any instruction MOVX @DPTR,A (with DPTR = 1234H 1237H) will generate the positive
polarity write strobe signal at pin P4.0. And the instruction MOV P4,#XX will output the bit3 to bit1 of
data #XX to pin P4.3 P4.1.
BIT
7
6
5
4
3
2
1
0
NAME
P43
P42
P41
P40
-
-
-
-
Reserve
Reserve
Reserve
Reserve
Port 4 Data bit which outputs to pin P4.3 at mode 0.
Port 4 Data bit. which outputs to pin P4.2 at mode 0.
Port 4 Data bit. which outputs to pin P4.1at mode 0.
Port 4 Data bit which outputs to pin P4.0 at mode 0.
; Base I/O address 1234H for P4.0
; P4.0 a write strobe signal and address line A0 and A1 are masked.
; P4.1 P4.3 as general I/O port which are the same as PORT1
; Write the P40SINV = 1 to inverse the P4.0 write strobe polarity
; default is negative.
; Disable CHPCON write attribute.
- 10 -
FUNCTION
Preliminary W78LE58