参数资料
| 型号： | P87C51RA2BA,512 |
| 厂商： | NXP Semiconductors |
| 文件页数： | 33/67页 |
| 文件大小： | 0K |
| 描述： | IC 80C51 MCU 512 RAM 44PLCC |
| 产品培训模块： | Migrating from 8/16-Bit MCUs to 32-Bit ARMs |
| 标准包装： | 26 |
| 系列： | 87C |
| 核心处理器： | 8051 |
| 芯体尺寸： | 8-位 |
| 速度： | 33MHz |
| 连通性： | EBI/EMI，UART/USART |
| 外围设备： | POR，PWM，WDT |
| 输入/输出数： | 32 |
| 程序存储器容量： | 16KB（16K x 8） |
| 程序存储器类型： | OTP |
| RAM 容量： | 512 x 8 |
| 电压 - 电源 (Vcc/Vdd)： | 2.7 V ~ 5.5 V |
| 振荡器型： | 内部 |
| 工作温度： | 0°C ~ 70°C |
| 封装/外壳： | 44-LCC（J 形引线） |
| 包装： | 管件 |
| 其它名称： | 568-7904-5 568-7904-5-ND 568-8355-5 935271889512 P87C51RA2BA P87C51RA2BA,512-ND P87C51RA2BA-ND |
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Philips Semiconductors
Product data
P87C51RA2/RB2/RC2/RD2
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
2003 Jan 24
39
––
ECOMn
CAPPn
CAPNn
MATn
TOGn
PWMn
ECCFn
CCAPM4
(DEH)
CH
CL
CCAP4H
CCAP4L
RESET
PCA TIMER/COUNTER
X0
00
16–BIT COMPARATOR
MATCH
ENABLE
WRITE TO
CCAP4L
RESET
WRITE TO
CCAP4H
10
1
CMOD
(D9H)
CIDL
WDTE
––
CPS1
CPS0
ECF
X
SU01612
MODULE 4
Figure 30. PCA Watchdog Timer mode (Module 4 only)
PCA Watchdog Timer
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 30 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:
1. periodically change the compare value so it will never match the
PCA timer,
2. periodically change the PCA timer value so it will never match
the compare values, or
3. 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
modules 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 applications the first
solution is the best option.
Figure 31 shows the code for initializing the watchdog timer.
Module 4 can be configured in either compare mode, and the WDTE
bit in CMOD must also be set. The user’s software then must
periodically change (CCAP4H,CCAP4L) to keep a match from
occurring with the PCA timer (CH,CL). This code is given in the
WATCHDOG routine in Figure 31.
This routine should not be part of an interrupt service routine,
because if the program counter goes astray and gets stuck in an
infinite loop, interrupts will still be serviced and the watchdog will
keep getting reset. Thus, the purpose of the watchdog would be
defeated. Instead, call this subroutine from the main program within
216 count of the PCA timer.
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相关代理商/技术参数 |
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| P87C51RA2BBD | 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:80C51 8-bit microcontroller family |
| P87C51RA2FA | 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:80C51 8-bit microcontroller family |
| P87C51RA2FA,512 | 功能描述:8位微控制器 -MCU 8B MCU 8K-64K/256-1K 2.7-5.5V 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 |
| P87C51RA2FA512 | 制造商:Rochester Electronics LLC 功能描述: 制造商:NXP 功能描述: 制造商:NXP Semiconductors 功能描述: |
| P87C51RB+4A | 制造商:PHILIPS-SEMI 功能描述: 制造商:NXP Semiconductors 功能描述:MCU 8-bit 8XC51 80C51 CISC 16KB EPROM 3.3V/5V 44-Pin PLCC |
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