AM186ES Advanced Micro Devices, AM186ES Datasheet - Page 88

• Manufacturer Part Number: AM186ES
• Description: microcontrollers provide a low-cost/ high-performance solution for embedded system designers who wish to use the x86 architecture.
• Manufacturer: Advanced Micro Devices

Table 6-1
Table 6-2
6-4
Bit 11: Test Mode (TEST)—This bit is reserved for an internal test mode. Setting this bit
activates a special test mode that generates early WDT timeouts. This bit is 0 after processor
reset.
Bits 10–8: Reserved
Bits 7–0: WDT Timeout Count (COUNT)—This field determines the duration of the
watchdog timer timeout interval. The duration is determined by using the value from the
column titled Exponent in Table 6-1 in the following equation.
Duration = 2
Where Duration is the timeout period in seconds, Exponent is the value from Table 6-2,
and Frequency is the processor frequency in Hz. For example, the following calculation
determines the WDT timeout period for a 40-MHz processor with the COUNT field set to 20h.
Duration
Setting more than one bit in the COUNT field results in the shorter timeout value. This field
is 80h after reset.
Watchdog Timer COUNT Settings
Watchdog Timer Duration
Bit 7
Exponent
X
X
X
X
X
X
X
0
1
10
20
21
22
23
24
25
26
Bit 6
X
X
X
X
X
X
0
1
0
= (2
= (16,777,216 cycles) / (40,000,000 cycles/second)
= .4194 seconds
Exponent
20 MHz
104 ms
209 ms
419 ms
838 ms
24
52 ms
1.67 s
3.35 s
51 s
Bit 5
cycles) / (40,000,000 Hz)
X
X
X
X
X
0
1
0
0
/ Frequency
Bit 4
25 MHz
167 ms
335 ms
671 ms
41 ms
83 ms
1.34 s
2.68 s
40 s
X
X
X
X
0
1
0
0
0
Refresh Control Unit
Bit 3
X
X
X
0
1
0
0
0
0
33 MHz
125 ms
251 ms
503 ms
31 ms
62 ms
1.00 s
2.01 s
30 s
Bit 2
X
X
0
1
0
0
0
0
0
40 MHz
104 ms
209 ms
419 ms
838 ms
26 ms
52 ms
1.67 s
25 s
Bit 1
0
X
1
0
0
0
0
0
0
Bit 0
0
1
0
0
0
0
0
0
0
Exponent
N/A
10
20
21
22
23
24
25
26