C8051F064EK Silicon Laboratories Inc, C8051F064EK Datasheet - Page 166

• Manufacturer Part Number: C8051F064EK
• Description: KIT EVAL FOR C8051F064
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F064EK

• Contents: Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
• Processor To Be Evaluated: C8051F06x
• Interface Type: USB
• Silicon Manufacturer: Silicon Labs
• Core Architecture: 8051
• Silicon Core Number: C8051F064
• Silicon Family Name: C8051F06x
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: C8051F064
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1219

C8051F060/1/2/3/4/5/6/7
14.7.1. Enable/Reset WDT
The watchdog timer is both enabled and reset by writing 0xA5 to the WDTCN register. The user's applica-
tion software should include periodic writes of 0xA5 to WDTCN as needed to prevent a watchdog timer
overflow. The WDT is enabled and reset as a result of any system reset.
14.7.2. Disable WDT
Writing 0xDE followed by 0xAD to the WDTCN register disables the WDT. The following code segment
illustrates disabling the WDT:
The writes of 0xDE and 0xAD must occur within 4 clock cycles of each other, or the disable operation is
ignored. Interrupts should be disabled during this procedure to avoid delay between the two writes.
14.7.3. Disable WDT Lockout
Writing 0xFF to WDTCN locks out the disable feature. Once locked out, the disable operation is ignored
until the next system reset. Writing 0xFF does not enable or reset the watchdog timer. Applications always
intending to use the watchdog should write 0xFF to WDTCN in the initialization code.
14.7.4. Setting WDT Interval
WDTCN.[2:0] control the watchdog timeout interval. The interval is given by the following equation:
166
4
3
CLR
MOV
MOV
SETB
+
WDTCN 2 0
EA
WDTCN,#0DEh
WDTCN,#0ADh
EA

–


T
sysclk
; disable all interrupts
; disable software watchdog timer
; re-enable interrupts
; where T
sysclk
is the system clock period.
Rev. 1.2