W77E468 查看數據表（PDF） - Winbond
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W77E468 Datasheet PDF : 84 Pages
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Preliminary W77E468
CLOCK CONTROL
Bit:
7
6
5
4
3
2
1
0
WD1 WD0 T2M T1M T0M MD2 MD1 MD0
Mnemonic: CKCON
Address: 8Eh
WD1-0: Watchdog timer mode select bits: These bits determine the time-out period for the watchdog
timer. In all four time-out options the reset time-out is 512 clocks more than the interrupt time-
out period.
WD1
0
0
1
1
WD0
0
1
0
1
Interrupt time-out
17
2
20
2
23
2
26
2
Reset time-out
17
2 + 512
20
2 + 512
23
2 + 512
26
2 + 512
T2M: Timer 2 clock select: When T2M is set to 1, timer 2 uses a divide by 4 clock, and when set to
0 it uses a divide by 12 clock.
T1M: Timer 1 clock select: When T1M is set to 1, timer 1 uses a divide by 4 clock, and when set to
0 it uses a divide by 12 clock.
T0M: Timer 0 clock select: When T0M is set to 1, timer 0 uses a divide by 4 clock, and when set to
0 it uses a divide by 12 clock.
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
0
0
0
0
1
1
1
1
MD1
0
0
1
1
0
0
1
1
MD0
0
1
0
1
0
1
0
1
Stretch value
0
1
2
3
4
5
6
7
MOVX duration
2 machine cycles
3 machine cycles (Default)
4 machine cycles
5 machine cycles
6 machine cycles
7 machine cycles
8 machine cycles
9 machine cycles
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