- 您现在的位置：买卖IC网 > PDF目录271213 > SST89E54RD2A-40-C-TQJE 8-BIT, FLASH, 40 MHz, MICROCONTROLLER, PQFP44 PDF资料下载
参数资料
| 型号： | SST89E54RD2A-40-C-TQJE |
| 元件分类： | 微控制器/微处理器 |
| 英文描述： | 8-BIT, FLASH, 40 MHz, MICROCONTROLLER, PQFP44 |
| 封装： | ROHS COMPLIANT, MS-026ACB, TQFP-44 |
| 文件页数： | 42/78页 |
| 文件大小： | 1671K |
| 代理商： | SST89E54RD2A-40-C-TQJE |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页当前第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页第69页第70页第71页第72页第73页第74页第75页第76页第77页第78页
Data Sheet
FlashFlex MCU
SST89E54RD2A/RDA / SST89E58RD2A/RDA
47
2008 Silicon Storage Technology, Inc.
S71339-02-000
02/08
7.0 WATCHDOG TIMER
The device offers a programmable Watchdog Timer (WDT)
for fail safe protection against software deadlock and auto-
matic recovery.
To protect the system against software deadlock, the user
software must refresh the WDT within a user-defined time
period. If the software fails to do this periodical refresh, an
internal hardware reset will be initiated if enabled (WDRE=
1). The software can be designed such that the WDT times
out if the program does not work properly.
The WDT in the device uses the system clock (XTAL1) as
its time base. So strictly speaking, it is a watchdog counter
rather than a watchdog timer. The WDT register will incre-
ment every 344,064 crystal clocks. The upper 8-bits of the
time base register (WDTD) are used as the reload register
of the WDT.
The WDTS flag bit is set by WDT overflow and is not
changed by WDT reset. User software can clear WDTS by
writing “1” to it.
Figure 7-1 provides a block diagram of the WDT. Two SFRs
(WDTC and WDTD) control watchdog timer operation.
During idle mode, WDT operation is temporarily sus-
pended, and resumes upon an interrupt exit from idle.
The time-out period of the WDT is calculated as follows:
Period = (255 - WDTD) * 344064 * 1/fCLK (XTAL1)
where WDTD is the value loaded into the WDTD register
and fOSC is the oscillator frequency.
FIGURE
7-1: Block Diagram of Programmable Watchdog Timer
1339 F22.0
WDT Upper Byte
WDT Reset
Internal Reset
344064
clks
Counter
CLK (XTAL1)
Ext. RST
WDTC
WDTD
相关PDF资料 |
PDF描述 |
|---|---|
| SST89E54RD2A-40-I-TQJE | 8-BIT, FLASH, 40 MHz, MICROCONTROLLER, PQFP44 |
| STM8L151C8T3STM8L151C8T3 | 8-BIT, FLASH, 16 MHz, RISC MICROCONTROLLER, PQFP48 |
| ST7FLITE10BF0B6 | 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PDIP20 |
| ST7FLITE10BY0B3 | 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PDIP16 |
| ST7FLITE19BF0U3TR | 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PQCC20 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| SST89E54RD2A-40-C-TQJE-T | 功能描述:8位微控制器 -MCU 4.5-5.5V FL Flex 8B 8051 Microcontroller RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| SST89E54RD2RD | 制造商:SST 制造商全称:Silicon Storage Technology, Inc 功能描述:FlashFlex51 MCU |
| SST89E54RD2-RD | 制造商:SST 制造商全称:Silicon Storage Technology, Inc 功能描述:FlashFlex51 MCU |
| SST89E54RD-33-C-PIE | 功能描述:8位微控制器 -MCU 24KB+1KB 33MHz RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| SST89E54RD-40-C-PI | 制造商:SST 制造商全称:Silicon Storage Technology, Inc 功能描述:FlashFlex51 MCU |
发布紧急采购，3分钟左右您将得到回复。