W79E648 Datasheet, PDF (15/80 Pages) Winbond – Fast 8051 Compatible microcontroller with a redesigned Processor

Preliminary W79E648
Port 1
Bit:
7
6
5
4
3
2
1
0
P1.7 P1.6 P1.5 P1.4 P1.3 P1.2 P1.1 P1.0
Mnemonic: P1
Address: 90h
P1.7−0: General purpose I/O port. Most instructions will read the port pins in case of a port read
access, however in case of read-modify-write instructions, the port latch is read. Some pins
also have alternate input or output functions. This alternate functions are described below:
P1.0 : T2
External I/O for Timer/Counter 2
P1.1 : T2EX Timer/Counter 2 Capture/Reload Trigger
Port 4 Control Register A
Bit:
7
6
5
4
3
2
1
0
P41M1 P41M0 P41C1 P41C0 P40M1 P40M0 P40C1 P40C0
Mnemonic: P4CONA
Address: 92h
Port 4 Control Register B
Bit:
7
P43M1
6
P43M0
5
P43C1
4
P43C0
3
P42M1
2
P42M0
1
P42C1
0
P42C0
Mnemonic: P4CONB
Address: 93h
BIT NAME
P4xM1, P4xM0
P4xC1, P4xC0
FUNCTION
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 P4xC1, P4xC0.
=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 P4xC1, P4xC0.
=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 P4xC1, P4xC0
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.
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Publication Release Date: 05/31/2004
Revision A1