w77e58 Winbond Electronics Corp America, w77e58 Datasheet - Page 16

• Manufacturer Part Number: w77e58
• Description: 8 Bit Microcontroller
• Manufacturer: Winbond Electronics Corp America

CLOCK CONTROL
WD1-0: Watchdog timer mode select bits: These bits determine the time-out period for the watchdog
T2M:
T1M:
T0M:
MD2-0: Stretch MOVX select bits: These three bits are used to select the stretch value for the MOVX
timer. In all four time-out options the reset time-out is 512 clocks more than the interrupt time-
out period.
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.
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.
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.
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.
Mnemonic: CKCON
MD2
0
0
0
0
1
1
1
1
Bit:
MD1
0
0
1
1
0
0
1
1
WD1
0
0
1
1
WD1
7
MD0
0
1
0
1
0
1
0
1
WD0
0
1
0
1
WD0
6
Stretch value
Interrupt time-out
2
2
2
2
17
20
23
26
T2M
0
1
2
3
4
5
6
7
- 16 -
5
T1M
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
4
Reset time-out
2
2
2
2
17
20
23
26
Preliminary W77E58
T0M
+ 512
+ 512
+ 512
+ 512
3
Address: 8Eh
MD2
2
MD1
1
MD0
0