參數(shù)資料
型號(hào)： ST72C171K2
廠商： 意法半導(dǎo)體
英文描述： 8-BIT MCU WITH 8K FLASH. ADC. WDG. SPI. SCI. TIMERS SPGAS (SOFTWARE PROGRAMMABLE GAIN AMPLIFIERS). OP-AMP
中文描述： 8位8K閃存微控制器。 ADC的。水分散粒劑。的SPI。脊髓損傷。定時(shí)器SPGAS（軟件可編程增益放大器）。運(yùn)放
文件頁數(shù)： 48/152頁
文件大?。?/td> 1384K
代理商： ST72C171K2
ST72C171
48/152
7.4 WATCHDOG TIMER (WDG)
7.4.1 Introduction
The Watchdog timer is used to detect the occur-
rence of a software fault, usually generated by ex-
ternal interference or by unforeseen logical condi-
tions, which causes the application program to
abandon its normal sequence. The Watchdog cir-
cuit generates an MCU reset on expiry of a pro-
grammed time period, unless the program refresh-
es the counter’s contents before the T6 bit be-
comes cleared.
7.4.2 Main Features
I
Programmable timer (64 increments of 12288
CPU cycles)
I
Programmable reset
I
Reset (if watchdog activated) when the T6 bit
reaches zero
I
Optional
reset
on
(configurable by option byte)
I
Hardware Watchdog selectable by option byte.
7.4.3 Functional Description
The counter value stored in the CR register (bits
T6:T0), is decremented every 12,288 machine cy-
HALT
instruction
cles, and the length of the timeout period can be
programmed by the user in 64 increments.
If the watchdog is activated (the WDGA bit is set)
and when the 7-bit timer (bits T6:T0) rolls over
from 40h to 3Fh (T6 becomes cleared), it initiates
a reset cycle pulling low the reset pin for typically
500ns.
The application program must write in the CR reg-
ister at regular intervals during normal operation to
prevent an MCU reset. The value to be stored in
the CR register must be between FFh and C0h
(see
Table 13 . Watchdog Timing (fCPU = 8
MHz)
):
– The WDGA bit is set (watchdog enabled)
– The T6 bit is set to prevent generating an imme-
diate reset
– The T5:T0 bits contain the number of increments
which represents the time delay before the
watchdog produces a reset.
Figure 29. Watchdog Block Diagram
RESET
WDGA
7-BIT DOWNCOUNTER
f
CPU
T6
T0
CLOCK DIVIDER
÷
12288
WATCHDOG CONTROL REGISTER (CR)
T1
T2
T3
T4
T5
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ST72C171K2B6 功能描述:8位微控制器 -MCU Flash 8K SPI/SCI 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(shí)鐘頻率:50 MHz 程序存儲(chǔ)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(fēng)格:SMD/SMT
ST72C171K2M6 功能描述:8位微控制器 -MCU Flash 8K SPI/SCI 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(shí)鐘頻率:50 MHz 程序存儲(chǔ)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(fēng)格:SMD/SMT
ST72C215G2B6 功能描述:8位微控制器 -MCU Flash 8K SPI 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(shí)鐘頻率:50 MHz 程序存儲(chǔ)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(fēng)格:SMD/SMT
ST72C215G2M3 制造商:STMicroelectronics 功能描述:MCU 8-Bit ST7 CISC 8KB Flash 3.3V/5V 28-Pin SO Tube 制造商:STMicroelectronics 功能描述:MCU 8BIT ST7 CISC 8KB FLASH 3.3V/5V 28SOIC - Rail/Tube
ST72C215G2M5 制造商:STMicroelectronics 功能描述:MCU 8BIT ST7 CISC 8KB FLASH 3.3V/5V 28SOIC - Rail/Tube
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