W79E217A Datasheet, PDF (30/207 Pages) Winbond – 8-bit Microcontroller

Preliminary W79E217A Data Sheet
PORT 4 CONTROL REGISTER B
Bit:
7
6
5
4
3
2
1
0
P43FUN1 P43FUN0 P43CMP1 P43CMP0 P42FUN1 P42FUN0 P42CMP1 P42CMP0
Mnemonic: P4CONB
Address: 93h
BIT NAME
FUNCTION
P4xFUN1, P4xFUN0
Port 4 alternate modes.
=00: Mode 0. P4.x is a general purpose I/O port which is the same as Port 1.
=01: Mode 1. P4.x is a Read Strobe signal for chip select purpose. The
address range depends on the SFR P4xAH, P4xAL and bits P4xCMP1,
P4xCMP0.
=10: Mode 2. P4.x is a Write Strobe signal for chip select purpose. The
address range depends on the SFR P4xAH, P4xAL and bits P4xCMP1,
P4xCMP0.
=11: Mode 3. P4.x is a Read/Write Strobe signal for chip select purpose. The address range
depends on the SFR P4xAH, P4xAL and bits P4xCMP1, P4xCMP0.
P4xCMP1, P4xCMP0
Port 4 Chip-select Mode address comparison:
=00: Compare the full address (16 bits length) with the base address registers
P4xAH and P4xAL.
=01: Compare the 15 high bits (A15-A1) of address bus with the base address
registers P4xAH and P4xAL.
=10: Compare the 14 high bits (A15-A2) of address bus with the base address
registers P4xAH and P4xAL.
=11: Compare the 8 high bits (A15-A8) of address bus with the base address registers P4xAH and
P4xAL.
P4.0 BASE ADDRESS LOW BYTE REGISTER
Bit:
7
6
5
4
3
2
1
0
A7
A6
A5
A4
A3
A2
A1
A0
Mnemonic: P40AL
Address: 94h
P4.0 BASE ADDRESS HIGH BYTE REGISTER
Bit:
7
6
5
4
3
2
1
0
A15
A14
A13
A12
A11
A10
A9
A8
Mnemonic: P40AH
Address: 95h
P4.1 BASE ADDRESS LOW BYTE REGISTER
Bit:
7
6
5
4
3
2
1
0
A7
A6
A5
A4
A3
A2
A1
A0
Mnemonic: P41AL
Address: 96h
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Publication Release Date: December 14, 2007
Revision A3.0