收藏本站
13
AT89C51RB2/RC2
4180E–8051–10/06
Port Types
AT89C51RB2/RC2 I/O ports (P1, P2, P3) implement the quasi-bidirectional output that
is common on the 80C51 and most of its derivatives. This output type can be used as
both an input and output without the need to reconfigure the port. This is possible
because when the port outputs a logic high, it is weakly driven, allowing an external
device to pull the pin low. When the pin is pulled low, it is driven strongly and able to sink
a fairly large current. These features are somewhat similar to an open drain output
except that there are three pull-up transistors in the quasi-bidirectional output that serve
different purposes. One of these pull-ups, called the "weak" pull-up, is turned on when-
ever the port latch for the pin contains a logic 1. The weak pull-up sources a very small
current that will pull the pin high if it is left floating. A second pull-up, called the "medium"
pull-up, is turned on when the port latch for the pin contains a logic 1 and the pin itself is
also at a logic 1 level. This pull-up provides the primary source current for a quasi-bidi-
rectional pin that is outputting a 1. If a pin that has a logic 1 on it is pulled low by an
external device, the medium pull-up turns off, and only the weak pull-up remains on. In
order to pull the pin low under these conditions, the external device has to sink enough
current to overpower the medium pull-up and take the voltage on the port pin below its
input threshold.
The third pull-up is referred to as the "strong" pull-up. This pull-up is used to speed up
low-to-high transitions on a quasi-bidirectional port pin when the port latch changes from
a logic 0 to a logic 1. When this occurs, the strong pull-up turns on for a brief time, two
CPU clocks, in order to pull the port pin high quickly. Then it turns off again.
The DPU bit (bit 7 in AUXR register) allows to disable the permanent weak pull up of all
ports when latch data is logical 0.
The quasi-bidirectional port configuration is shown in Figure 3.
Figure 3. Quasi-Bidirectional Output
2 CPU
Input
Pin
Strong
Medium
N
Weak
P
Clock Delay
Port Latch
Data
DPU
AUXR.7
PP
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
PIC16C72A-04/SO IC MCU OTP 2KX14 A/D PWM 28SOIC
AT89C51ID2-RLTIM IC 8051 MCU FLASH 64K 44VQFP
AT89C51IC2-SLSIL IC 8051 MCU FLASH 32K 44PLCC
AT89C51CC03U-RLTIM IC 8051 MCU FLASH 64K 44VQFP
PIC24EP64MC204-I/PT MCU 16BIT 64KB FLASH 44TQFP
AT89C51CC03U-RDTIM IC 8051 MCU FLASH 64K 64VQFP
AT89C51CC03U-7CTIM IC 8051 MCU FLASH 64K 64BGA
AT89C51CC03C-S3SIM IC 8051 MCU FLASH 64K 52PLCC
相关代理商/技术参数
AT89C51RB2-3CSUL 功能描述:8位微控制器 -MCU 8-bit 16K Flash C51RB2 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
AT89C51RB2-3CSUM 功能描述:8位微控制器 -MCU C51RB2 FLASH 5V 16k ind 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
AT89C51RB2L1-RLTUL 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
AT89C51RB2-RLRIL 功能描述:IC MCU FLASH 8051 16K 3V 44-VQFP RoHS:否 类别:集成电路 (IC) >> 嵌入式 - 微控制器， 系列:89C 标准包装:1,500 系列:AVR® ATtiny 核心处理器:AVR 芯体尺寸:8-位 速度:16MHz 连通性:I²C，LIN，SPI，UART/USART，USI 外围设备:欠压检测/复位，POR，PWM，温度传感器，WDT 输入/输出数:16 程序存储器容量:8KB（4K x 16） 程序存储器类型:闪存 EEPROM 大小:512 x 8 RAM 容量:512 x 8 电压 - 电源 (Vcc/Vdd):2.7 V ~ 5.5 V 数据转换器:A/D 11x10b 振荡器型:内部 工作温度:-40°C ~ 125°C 封装/外壳:20-SOIC（0.295"，7.50mm 宽） 包装:带卷 (TR)
AT89C51RB2-RLRIM 功能描述:IC MCU FLASH 8051 16K 5V 44-VQFP RoHS:否 类别:集成电路 (IC) >> 嵌入式 - 微控制器， 系列:89C 产品培训模块:MCU Product Line Introduction AVR® UC3 Introduction 标准包装:2,500 系列:AVR®32 UC3 B 核心处理器:AVR 芯体尺寸:32-位 速度:60MHz 连通性:I²C，IrDA，SPI，SSC，UART/USART，USB 外围设备:欠压检测/复位，DMA，POR，PWM，WDT 输入/输出数:28 程序存储器容量:128KB（128K x 8） 程序存储器类型:闪存 EEPROM 大小:- RAM 容量:32K x 8 电压 - 电源 (Vcc/Vdd):1.65 V ~ 1.95 V 数据转换器:A/D 6x10b 振荡器型:内部 工作温度:-40°C ~ 85°C 封装/外壳:48-TQFP 包装:带卷 (TR) 配用:ATSTK600-TQFP48-ND - STK600 SOCKET/ADAPTER 48-TQFPATAVRONEKIT-ND - KIT AVR/AVR32 DEBUGGER/PROGRMMRATEVK1101-ND - KIT DEV/EVAL FOR AVR32 AT32UC3B 其它名称:AT32UC3B1128-AUR-NDAT32UC3B1128-AURTR
AT89C51RB2-RLRUL 功能描述:8位微控制器 -MCU C51RB2 FLASH 3V 16k ind 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
AT89C51RB2-RLRUM 功能描述:8位微控制器 -MCU C51RB2 FLASH 5V 16k ind 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
AT89C51RB2-RLTCM 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:8-bit Microcontroller with 16K/ 32K Bytes Flash