- 您现在的位置：买卖IC网 > PDF目录381506 > AT89LS52-16PI (ATMEL CORP) -bit AVR Microcontroller with 8K Bytes In- System Programmable Flash PDF资料下载
参数资料
| 型号： | AT89LS52-16PI |
| 厂商： | ATMEL CORP |
| 元件分类： | 微控制器/微处理器 |
| 英文描述： | -bit AVR Microcontroller with 8K Bytes In- System Programmable Flash |
| 中文描述： | 8-BIT, FLASH, 16 MHz, MICROCONTROLLER, PDIP40 |
| 封装： | 0.600 INCH, PLASTIC, MS-011AC, DIP-40 |
| 文件页数： | 10/39页 |
| 文件大小： | 469K |
| 代理商： | AT89LS52-16PI |
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页当前第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
10
AT89LS52
2601A–12/01
Watchdog
Timer
(One-time
Enabled with
Reset-out)
The WDT is intended as a recovery method in situations where the CPU may be subjected to
software upsets. The WDT consists of a 14-bit counter and the Watchdog Timer Reset
(WDTRST) SFR. The WDT is defaulted to disable from exiting reset. To enable the WDT, a
user must write 01EH and 0E1H in sequence to the WDTRST register (SFR location 0A6H).
When the WDT is enabled, it will increment every machine cycle while the oscillator is running.
The WDT timeout period is dependent on the external clock frequency. There is no way to dis-
able the WDT except through reset (either hardware reset or WDT overflow reset). When
WDT overflows, it will drive an output RESET HIGH pulse at the RST pin.
Using the WDT
To enable the WDT, a user must write 01EH and 0E1H in sequence to the WDTRST register
(SFR location 0A6H). When the WDT is enabled, the user needs to service it by writing 01EH
and 0E1H to WDTRST to avoid a WDT overflow. The 14-bit counter overflows when it reaches
16383 (3FFFH), and this will reset the device. When the WDT is enabled, it will increment
every machine cycle while the oscillator is running. This means the user must reset the WDT
at least every 16383 machine cycles. To reset the WDT the user must write 01EH and 0E1H
to WDTRST. WDTRST is a write-only register. The WDT counter cannot be read or written.
When WDT overflows, it will generate an output RESET pulse at the RST pin. The RESET
pulse duration is 98xTOSC, where TOSC=1/FOSC. To make the best use of the WDT, it
should be serviced in those sections of code that will periodically be executed within the time
required to prevent a WDT reset.
WDT During
Power-down
and Idle
In Power-down mode the oscillator stops, which means the WDT also stops. While in Power-
down mode, the user does not need to service the WDT. There are two methods of exiting
Power-down mode: by a hardware reset or via a level-activated external interrupt which is
enabled prior to entering Power-down mode. When Power-down is exited with hardware reset,
servicing the WDT should occur as it normally does whenever the AT89LS52 is reset. Exiting
Power-down with an interrupt is significantly different. The interrupt is held low long enough for
the oscillator to stabilize. When the interrupt is brought high, the interrupt is serviced. To pre-
vent the WDT from resetting the device while the interrupt pin is held low, the WDT is not
started until the interrupt is pulled high. It is suggested that the WDT be reset during the inter-
rupt service for the interrupt used to exit Power-down mode.
To ensure that the WDT does not overflow within a few states of exiting Power-down, it is best
to reset the WDT just before entering Power-down mode.
Before going into the IDLE mode, the WDIDLE bit in SFR AUXR is used to determine whether
the WDT continues to count if enabled. The WDT keeps counting during IDLE (WDIDLE bit =
0) as the default state. To prevent the WDT from resetting the AT89LS52 while in IDLE mode,
the user should always set up a timer that will periodically exit IDLE, service the WDT, and
reenter IDLE mode.
With WDIDLE bit enabled, the WDT will stop to count in IDLE mode and resumes the count
upon exit from IDLE.
UART
The UART in the AT89LS52 operates the same way as the UART in the AT89C51 and
AT89C52. For further information on the UART operation, refer to the ATMEL Web site
(http://www.atmel.com). From the home page, select ‘Products’, then ‘8051-Architecture Flash
Microcontroller’, then ‘Product Overview’.
相关PDF资料 |
PDF描述 |
|---|---|
| AT89LS53-12JI | 8-Bit Microcontroller with 12K Bytes Flash |
| AT89LS53-12PC | 8-Bit Microcontroller with 12K Bytes Flash |
| AT89LS53-12PI | 8-Bit Microcontroller with 12K Bytes Flash |
| AT89LS53-12AC | DBMY9W4S |
| AT89LS53-12AI | 8-Bit Microcontroller with 12K Bytes Flash |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AT89LS52-16PU | 功能描述:8位微控制器 -MCU LO-VLTG 8K ISP FLASH -16MHZ 2.7-5.5V 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 |
| AT89LS52-24AU | 功能描述:8位微控制器 -MCU 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 |
| AT89LS52-24JU | 功能描述:8位微控制器 -MCU 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 |
| AT89LS52-24PU | 功能描述:8位微控制器 -MCU 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 |
| AT89LS53-12AC | 功能描述:8位微控制器 -MCU 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 |
发布紧急采购，3分钟左右您将得到回复。