参数资料
| 型号： | AT89LS52-16PI |
| 厂商： | Atmel |
| 文件页数： | 3/39页 |
| 文件大小： | 0K |
| 描述： | IC 8051 MCU FLASH 8K 40DIP |
| 标准包装： | 9 |
| 系列： | 89LS |
| 核心处理器： | 8051 |
| 芯体尺寸： | 8-位 |
| 速度： | 16MHz |
| 连通性： | UART/USART |
| 外围设备： | WDT |
| 输入/输出数： | 32 |
| 程序存储器容量： | 8KB（8K x 8） |
| 程序存储器类型： | 闪存 |
| RAM 容量： | 256 x 8 |
| 电压 - 电源 (Vcc/Vdd)： | 2.7 V ~ 4 V |
| 振荡器型： | 内部 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 40-DIP（0.600"，15.24mm） |
| 包装： | 管件 |
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11
2601C–MICRO–06/08
AT89LS52
7.
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 disable
the WDT except through reset (either hardware reset or WDT overflow reset). When WDT over-
flows, it will drive an output RESET HIGH pulse at the RST pin.
7.1
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 dura-
tion 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.
7.2
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 prevent
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 interrupt 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.
相关PDF资料 |
PDF描述 |
|---|---|
| AT89LS52-16PC | IC MCU 8K FLASH LV 16MHZ 40-DIP |
| AT89LS52-16JI | IC 8051 MCU FLASH 8K 44PLCC |
| AT89LS52-16JC | IC MCU 8K FLASH LV 16MHZ 44-PLCC |
| AT89S52-24PC | IC MCU 8K FLASH 24MHZ 40-DIP |
| AT89S52-24JI | IC MCU 8K FLASH 24MHZ 44-PLCC |
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 |
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