參數(shù)資料
型號(hào): uPSD3212C
廠商: 意法半導(dǎo)體
英文描述: Flash Programmable System Devices with 8032 Microcontroller Core and 16Kbit SRAM(帶8032微控制器內(nèi)核和16Kbit SRAM的FLASH可編程系統(tǒng)器件)
中文描述: 閃存可編程系統(tǒng)設(shè)備與8032微控制器內(nèi)核和16Kbit的SRAM(帶8032微控制器內(nèi)核和16Kbit SRAM的的閃存可編程系統(tǒng)器件)
文件頁數(shù): 48/151頁
文件大?。?/td> 1194K
代理商: UPSD3212C
uPSD3212C, uPSD3212CV
48/151
WATCHDOG TIMER
The hardware Watchdog Timer (WDT) resets the
uPSD321X Devices when it overflows. The WDT
is intended as a recovery method in situations
where the CPU may be subjected to a software
upset. To prevent a system reset the timer must be
reloaded in time by the application software. If the
processor suffers a hardware/software malfunc-
tion, the software will fail to reload the timer. This
failure will result in a reset upon overflow thus pre-
venting the processor running out of control.
In the Idle Mode the watchdog timer and reset cir-
cuitry remain active. The WDT consists of a 22-bit
counter, the Watchdog Timer RESET (WDRST)
SFR and Watchdog Key Register (WDKEY).
Since the WDT is automatically enabled while the
processor is running. the user only needs to be
concerned with servicing it.
The 22-bit counter overflows when it reaches
4194304 (3FFFFFH). The WDT increments once
every machine cycle.
This means the user must reset the WDT at least
every 4194304 machine cycles (1.258 seconds at
40MHz). To reset the WDT the user must write a
value between 00-7EH to the WDRST register.
The value that is written to the WDRST is loaded
to the 7MSB of the 22-bit counter. This allows the
user to pre-loaded the counter to an initial value to
generate a flexible Watchdog time out period.
Writing a “00” to WDRST clears the counter.
The watchdog timer is controlled by the watchdog
key register, WDKEY. Only pattern 01010101
(=55H), disables the watchdog timer. The rest of
pattern combinations will keep the watchdog timer
enabled. This security key will prevent the watch-
dog timer from being terminated abnormally when
the function of the watchdog timer is needed.
In Idle Mode, the oscillator continues to run. To
prevent the WDT from resetting the processor
while in Idle, the user should always set up a timer
that will periodically exit Idle, service the WDT, and
re-enter Idle Mode.
Table 32. Watchdog Timer Key Register (WDKEY: 0AEH)
Table 33. Description of the WDKEY Bits
7
6
5
4
3
2
1
0
WDKEY7
WDKEY6
WDKEY5
WDKEY4
WDKEY3
WDKEY2
WDKEY1
WDKEY0
Bit
Symbol
Function
7 to 0
WDKEY7 to
WDKEY0
Enable or disable Watchdog Timer.
01010101 (=55h): disable watchdog timer. Others: enable watchdog timer
相關(guān)PDF資料
PDF描述
uPSD3212CV Flash Programmable System Devices with 8032 Microcontroller Core and 16Kbit SRAM(帶8032微控制器內(nèi)核和16Kbit SRAM的FLASH可編程系統(tǒng)器件)
uPSD3212 Flash Programmable System Device with 8032 Microcontroller Core(嵌入高速“8032微控制器核”的Flash型可編程系統(tǒng)器件)
UPSD3215A-24T1 8-bit Microcontroller with 2/4/8K Bytes In-System Programmable Flash
UPSD3215AV-40T6T 8-bit Microcontroller with 2/4/8K Bytes In-System Programmable Flash
UPSD3215BV-24U1 8-bit Microcontroller with 2/4/8K Bytes In-System Programmable Flash
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
UPSD3212C-24T1T 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Flash Programmable System Devices with 8032 Microcontroller Core and 16Kbit SRAM
UPSD3212C-24T6T 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Flash Programmable System Devices with 8032 MCU with USB and Programmable Logic
UPSD3212C-24U1T 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Flash Programmable System Devices with 8032 Microcontroller Core and 16Kbit SRAM
UPSD3212C-24U6T 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Flash Programmable System Devices with 8032 MCU with USB and Programmable Logic
UPSD3212C-40T1T 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Flash Programmable System Devices with 8032 Microcontroller Core and 16Kbit SRAM