W79E632A Datasheet, PDF (13/79 Pages) Winbond – 8-BIT MICROCONTROLLER

W79E632A/W79L632A
MD2−0: Stretch MOVX select bits: These three bits are used to select the stretch value for the MOVX
instruction. Using a variable MOVX length enables the user to access slower external memory
devices or peripherals without the need for external circuits. The RD or WR strobe will be
stretched by the selected interval. When accessing the on-chip SRAM, the MOVX instruction is
always in 2 machine cycles regardless of the stretch setting. By default, the stretch has value of
1. If the user needs faster accessing, then a stretch value of 0 should be selected.
MD2 MD1 MD0 Stretch value MOVX duration
Port 1
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
0
2 machine cycles
1
3 machine cycles (Default)
2
4 machine cycles
3
5 machine cycles
4
6 machine cycles
5
7 machine cycles
6
8 machine cycles
7
9 machine cycles
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
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Publication Release Date: Nov. 11, 2009
Revision A10