W77E516 Просмотр технического описания (PDF) - Winbond
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W77E516 Datasheet PDF : 85 Pages
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Preliminary W77E516
Clock Control
Bit:
7
WD1
6
WD0
Mnemonic: CKCON
5
T2M
4
T1M
3
T0M
2
MD2
1
MD1
Address: 8Eh
0
MD0
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
217
220
223
226
Reset time-out
217 + 512
220 + 512
223 + 512
226 + 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
MOVXinstruction. Using a variable MOVX length enables the user to access slower
external memorydevices 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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