UPSD3254 STMICROELECTRONICS [STMicroelectronics], UPSD3254 Datasheet - Page 53

• Manufacturer Part Number: UPSD3254
• Description: Flash Programmable System Devices with 8032 Microcontroller Core
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Watchdog reset pulse width depends on the clock
frequency. The reset period is Tf
Figure 21. RESET Pulse Width
Table 34. Watchdog Timer Clear Register (WDRST: 0A6H)
Table 35. Description of the WDRST Bits
Note: The Watchdog Timer (WDT) is enabled at power-up or reset and must be served or disabled.
Reserved
6 to 0
Bit
7
7
WDRST6 to
WDRST6
WDRST0
Symbol
—
6
Reserved
To reset watchdog timer, write any value beteen 00h and 7Eh to this register.
This value is loaded to the 7 most significant bits of the 22-bit counter.
For example: MOV WDRST,#1EH
WDRST5
5
OSC
(about 6.291 seconds at 8Mhz)
(1.258 second at 40Mhz)
x 12 x 2
UPSD3254A, UPSD3254BV, UPSD3253B, UPSD3253BV
Reset period
WDRST4
Reset pulse width (about 10ms at 40Mhz, about 50ms at 8Mhz)
22
4
.
The RESET pulse width is Tf
WDRST3
3
Function
WDRST2
2
WDRST1
OSC
1
x 12 x 2
AI06823
WDRST0
15
0
.
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