参数资料
型号: EVAL-ADUC832QSZ
厂商: Analog Devices Inc
文件页数: 61/92页
文件大小: 0K
描述: KIT DEV FOR ADUC832 QUICK START
产品培训模块: Process Control
标准包装: 1
系列: QuickStart™ 套件
类型: MCU
适用于相关产品: ADuC832
所含物品: 评估板,线缆,电源,软件和文档
其它名称: EVAL-ADUC832QS
EVAL-ADUC832QS-ND
ADuC832
Data Sheet
Rev. B | Page 64 of 92
WATCHDOG TIMER
The purpose of the watchdog timer is to generate a device reset
or interrupt within a reasonable amount of time if the ADuC832
enters an erroneous state, possibly due to a programming error
or electrical noise. The watchdog function can be disabled by
clearing the watchdog enable (WDE) bit in the watchdog
control (WDCON) SFR. When enabled, the watchdog circuit
generates a system reset or interrupt (WDS) if the user program
fails to set the watchdog (WDE) bit within a predetermined
amount of time (see the PRE[3:0] bits in WDCON). The
watchdog timer itself is a 16-bit counter that is clocked directly
from the 32.768 kHz external crystal. The watchdog timeout
interval can be adjusted via the PRE[3:0] bits in WDCON. Full
control and status of the watchdog timer function can be con-
trolled via the watchdog timer control SFR (WDCON). The
WDCON SFR can only be written by user software if the double
write sequence described in the WDWR description (see Table 32)
is initiated on every write access to the WDCON SFR.
WDCON (Watchdog Timer Control Register)
SFR Address:
C0H
Power-On Default Value:
10H
Bit Addressable:
Yes
Table 32. WDCON SFR Bit Designations
Bit
Name
Description
[7:4]
PRE[3:0]
Watchdog timer prescale bits.
The watchdog timeout period is given by the following equation:
tWD = (2PRE × (29/fXTAL)).
where 0 ≤ PRE ≤ 7 and fXTAL = 32.768 kHz).
PRE3
PRE2
PRE1
PRE0
Timeout Period (ms)
Action
0
15.6
Reset or Interrupt
0
1
31.2
Reset or Interrupt
0
1
0
62.5
Reset or Interrupt
0
1
125
Reset or Interrupt
0
1
0
250
Reset or Interrupt
0
1
0
1
500
Reset or Interrupt
0
1
0
1000
Reset or Interrupt
0
1
2000
Reset or Interrupt
1
0
0.0
Immediate Reset
PRE[3:0] > 1000 = reserved.
[3]
WDIR
Watchdog interrupt response enable bit.
If this bit is set by the user, the watchdog generates an interrupt response instead of a system reset when the watchdog
timeout period has expired. This interrupt is not disabled by the CLR EA instruction and it is also a fixed, high priority
interrupt. If the watchdog is not being used to monitor the system, it can alternatively be used as a timer. The prescaler is
used to set the timeout period in which an interrupt is generated.
[2]
WDS
Watchdog status bit.
Set by the watchdog controller to indicate that a watchdog timeout has occurred.
Cleared by writing a 0 or by an external hardware reset. It is not cleared by a watchdog reset.
[1]
WDE
Watchdog enable bit.
Set by user to enable the watchdog and clear its counters. If this bit is not set by the user within the watchdog timeout
period, the watchdog generates a reset or interrupt, depending on WDIR.
Cleared under the following conditions: user writes 0, watchdog reset (WDIR = 0), hardware reset, or PSM interrupt.
[0]
WDWR
Watchdog write enable bit.
To write data into the WDCON SFR involves a double instruction sequence. The WDWR bit must be set and the very next
instruction must be a write instruction to the WDCON SFR. See the Example Write Instruction section.
Example Write Instruction
CLR
EA
;disable interrupts while writing
;to WDT
SETB
WDWR
;allow write to WDCON
MOV
WDCON,
#72H
;enable WDT for 2.0 sec timeout
SETB
EA
;enable interrupts again (if rqd)
相关PDF资料
PDF描述
HBM15DRXS CONN EDGECARD 30POS DIP .156 SLD
PCX1H270MCL1GS CAP ALUM 27UF 50V 20% SMD
HSM08DRKI CONN EDGECARD 16POS DIP .156 SLD
0210490857 CABLE JUMPER 1.25MM .051M 17POS
EVAL-ADUC831QSZ KIT DEV FOR ADUC831 QUICK START
相关代理商/技术参数
参数描述
EVAL-ADUC834QS 制造商:Analog Devices 功能描述:DATA ACQ SYS, MICROCNVRTR, DUAL 16BIT/24BIT - ADCS W/ EMBEDD - Bulk 制造商:Analog Devices 功能描述:8052 ADUC834 QUICKSTART DEV KIT
EVAL-ADUC834QSZ 功能描述:KIT DEV QUICK START ADUC834 RoHS:是 类别:编程器,开发系统 >> 通用嵌入式开发板和套件(MCU、DSP、FPGA、CPLD等) 系列:QuickStart™ 套件 标准包装:1 系列:PICDEM™ 类型:MCU 适用于相关产品:PIC10F206,PIC16F690,PIC16F819 所含物品:板,线缆,元件,CD,PICkit 编程器 产品目录页面:659 (CN2011-ZH PDF)
EVAL-ADUC836QS 制造商:Analog Devices 功能描述:MCU 8BIT 8052 CISC 62KB+4KB FLASH 3.6V 48LQFP - Bulk 制造商:Analog Devices 功能描述:KIT- ADUC836 DEV SYSTEM
EVAL-ADUC841QS 制造商:AD 制造商全称:Analog Devices 功能描述:MicroConverter 12-Bit ADCs and DACs with Embedded High Speed 62-kB Flash MCU
EVAL-ADUC841QSP2 制造商:AD 制造商全称:Analog Devices 功能描述:MicroConverter 12-Bit ADCs and DACs with Embedded High Speed 62-kB Flash MCU