參數(shù)資料
型號: C8051F012
廠商: Cygnal Technologies
英文描述: 20 MIPS,32k Flash,256 Ram,10bit ADC,32 Pin MCU(20 MIPS,32k 閃速存儲器,256 Ram,10位 ADC,32 腳 MCU)
中文描述: 20 MIPS的,32K閃存,256羊,10位ADC,32引腳微控制器(20 MIPS的,32K的閃速存儲器,256,羊,10位ADC和32腳微控制器)
文件頁數(shù): 95/170頁
文件大?。?/td> 1294K
代理商: C8051F012
4.2001; Rev. 1.3
CYGNAL Integrated Products, Inc.
2001
Page 95
C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7
PRELIMINARY
13.8.1. Watchdog Usage
The WDT consists of a 21-bit timer running from the programmed system clock. The timer measures the period
between specific writes to its control register. If this period exceeds the programmed limit, a WDT reset is
generated. The WDT can be enabled and disabled as needed in software, or can be permanently enabled if desired.
Watchdog features are controlled via the Watchdog Timer Control Register (WDTCN) shown in Figure 13.3.
Enable/Reset WDT
The watchdog timer is both enabled and the countdown restarted by writing 0xA5 to the WDTCN register. The
user’s application software should include periodic writes of 0xA5 to WDTCN as needed to prevent a watchdog
timer overflow. The WDT is enabled and restarted as a result of any system reset.
Disable WDT
Writing 0xDE followed by 0xAD to the WDTCN register disables the WDT. The following code segment illustrates
disabling the WDT.
CLR
EA
; disable all interrupts
MOV
WDTCN,#0DEh ; disable software
MOV
WDTCN,#0ADh ; watchdog timer
SETB
EA
; re-enable interrupts
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.
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 their initialization code.
Setting WDT Interval
WDTCN.[2:0] control the watchdog timeout interval. The interval is given by the following equation:
4
3+WDTCN[2:0]
x T
SYSCLK
, (where T
SYSCLK
is the system clock period).
For a 2MHz system clock, this provides an interval range of 0.032msec to 524msec. WDTCN.7 must be a 0 when
setting this interval. Reading WDTCN returns the programmed interval. WDTCN.[2:0] is 111b after a system reset.
Figure 13.3. WDTCN: Watchdog Timer Control Register
R/W
Bit7
R/W
Bit6
R/W
Bit5
R/W
Bit4
R/W
Bit3
R/W
Bit2
R/W
Bit1
R/W
Bit0
Reset Value
xxxxx111
SFR Address:
0xFF
Bits7-0: WDT Control
Writing 0xA5 both enables and reloads the WDT.
Writing 0xDE followed within 4 clocks by 0xAD disables the WDT.
Writing 0xFF locks out the disable feature.
Bit4:
Watchdog Status Bit (when Read)
Reading the WDTCN.[4] bit indicates the Watchdog Timer Status.
0: WDT is inactive
1: WDT is active
Bits2-0: Watchdog Timeout Interval Bits
The WDTCN.[2:0] bits set the Watchdog Timeout Interval. When writing these bits,
WDTCN.7 must be set to 0.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
C8051F012/005 制造商:Silicon Laboratories Inc 功能描述:
C8051F012-GQ 功能描述:8位微控制器 -MCU 32KB 10ADC 32P MCU RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
C8051F012-GQR 功能描述:8位微控制器 -MCU 32KB 10ADC 32Pin MCU Tape and Reel RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
C8051F012-PX0005GQ 制造商:Silicon Laboratories Inc 功能描述:
C8051F012R 功能描述:8位微控制器 -MCU C 10Bit 32Pin RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT