参数资料
型号: AT87C5112
厂商: Atmel Corp.
英文描述: 8-bit Microcontroller with A/D Converter
中文描述: 8位微控制器与A / D转换器
文件页数: 61/97页
文件大小: 1229K
代理商: AT87C5112
61
AT8xC5112
4191B
8051
04/03
Figure 28.
PCA PWM Mode
An on-board watchdog timer is available with the PCA to improve the reliability of the
system without increasing chip count. Watchdog timers are useful for systems that are
susceptible to noise, power glitches, or electrostatic discharge. Module 4 is the only
PCA module that can be programmed as a watchdog. However, this module can still be
used for other modes if the watchdog is not needed. Figure 26 shows a diagram of how
the watchdog works. The user pre-loads a 16-bit value in the compare registers. Just
like the other compare modes, this 16-bit value is compared to the PCA timer value. If a
match is allowed to occur, an internal reset will be generated. This will not cause the
RST pin to be driven high.
In order to hold off the reset, the user has three options:
periodically change the compare value so it will never match the PCA timer
periodically change the PCA timer value so it will never match the compare values
or
disable the watchdog by clearing the WDTE bit before a match occurs and then re-
enable it.
The first two options are more reliable because the watchdog timer is never disabled as
in option #3. If the program counter ever goes astray, a match will eventually occur and
cause an internal reset. The second option is also not recommended if other PCA mod-
ules are being used. Remember, the PCA timer is the time base for all modules;
changing the time base for other modules would not be a good idea. Thus, in most appli-
cations the first solution is the best option.
This watchdog timer won
t generate a reset out on the reset pin.
CL
CCAPnH
CCAPnL
ECOMn
CCAPMn, n= 0 to 4
0xDA to 0xDE
CAPNn
MATn
TOGn
PWMn
ECCFn
CAPPn
8 bit comparator
CEXn
0
1
>
Enable
PCA counter/timer
Overflow
<
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AT87C51RB2 制造商:IRF 制造商全称:International Rectifier 功能描述:High Performance 8-bit Microcontroller
AT87C51RB2-3CSUL 功能描述:8位微控制器 -MCU OTP RB/16K 40MHZ 3V 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
AT87C51RB2-3CSUM 功能描述:8位微控制器 -MCU 32KB SCMOS 3/2 .5 OTP 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
AT87C51RB2-RLRUM 功能描述:8位微控制器 -MCU 32KB 2.5u 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
AT87C51RB2-RLTUL 功能描述:8位微控制器 -MCU OTP RB/16K 40MHZ 3V 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