參數(shù)資料
型號： PIC16F871-E/L
廠商： Microchip Technology
文件頁數(shù)： 75/143頁
文件大?。?/td> 0K
描述： IC MCU CMOS 20MHZ 2K FLSH 44PLCC
標準包裝： 27
系列： PIC® 16F
核心處理器： PIC
芯體尺寸： 8-位
速度： 20MHz
連通性： UART/USART
外圍設備： 欠壓檢測/復位，POR，PWM，WDT
輸入/輸出數(shù)： 33
程序存儲器容量： 3.5KB（2K x 14）
程序存儲器類型： 閃存
EEPROM 大小： 64 x 8
RAM 容量： 128 x 8
電壓 - 電源 (Vcc/Vdd)： 4 V ~ 5.5 V
數(shù)據(jù)轉換器： A/D 8x10b
振蕩器型： 外部
工作溫度： -40°C ~ 125°C
封裝/外殼： 44-LCC（J 形引線）
包裝： 管件
2003 Microchip Technology Inc.
DS30569B-page 35
PIC16F870/871
4.2
PORTB and the TRISB Register
PORTB is an 8-bit wide, bi-directional port. The corre-
sponding data direction register is TRISB. Setting a
TRISB bit (= 1) will make the corresponding PORTB
pin an input (i.e., put the corresponding output driver in
a Hi-Impedance mode). Clearing a TRISB bit (= 0) will
make the corresponding PORTB pin an output (i.e., put
the contents of the output latch on the selected pin).
Three pins of PORTB are multiplexed with the Low
Voltage Programming function: RB3/PGM, RB6/PGC
and RB7/PGD. The alternate functions of these pins
are described in the Special Features Section.
Each of the PORTB pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is per-
formed by clearing bit RBPU (OPTION_REG<7>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on a Power-on Reset.
FIGURE 4-3:
BLOCK DIAGRAM OF
RB3:RB0 PINS
Four of PORTB’s pins, RB7:RB4, have an interrupt-on-
change feature. Only pins configured as inputs can
cause this interrupt to occur (i.e., any RB7:RB4 pin
configured as an output is excluded from the interrupt-
on-change comparison). The input pins (of RB7:RB4)
are compared with the old value latched on the last
read of PORTB. The “mismatch” outputs of RB7:RB4
are OR’ed together to generate the RB Port Change
Interrupt with flag bit RBIF (INTCON<0>).
This interrupt can wake the device from SLEEP. The
user, in the Interrupt Service Routine, can clear the
interrupt in the following manner:
a)
Any read or write of PORTB. This will end the
mismatch condition.
b)
Clear flag bit RBIF.
A mismatch condition will continue to set flag bit RBIF.
Reading PORTB will end the mismatch condition and
allow flag bit RBIF to be cleared.
The interrupt-on-change feature is recommended for
wake-up on key depression operation and operations
where PORTB is only used for the interrupt-on-change
feature. Polling of PORTB is not recommended while
using the interrupt-on-change feature.
This interrupt on mismatch feature, together with soft-
ware configurable pull-ups on these four pins, allow
easy interface to a keypad and make it possible for
wake-up on key-depression. Refer to the Embedded
Control Handbook, “Implementing Wake-up on Key
Stroke” (AN552).
RB0/INT is an external interrupt input pin and is
configured using the INTEDG bit (OPTION_REG<6>).
RB0/INT is discussed in detail in Section 11.10.1.
FIGURE 4-4:
BLOCK DIAGRAM OF
RB7:RB4 PINS
Data Latch
RBPU(2)
P
VDD
Q
D
CK
Q
D
CK
QD
EN
Data Bus
WR Port
WR TRIS
RD TRIS
RD Port
Weak
Pull-up
RD Port
RB0/INT
I/O pin(1)
TTL
Input
Buffer
Schmitt Trigger
Buffer
TRIS Latch
Note 1:
I/O pins have diode protection to VDD and VSS.
2:
To enable weak pull-ups, set the appropriate TRIS
bit(s) and clear the RBPU bit (OPTION_REG<7>).
RB3/PGM
Data Latch
From other
RBPU(2)
P
VDD
I/O pin(1)
Q
D
CK
Q
D
CK
QD
EN
QD
EN
Data Bus
WR Port
WR TRIS
Set RBIF
TRIS Latch
RD TRIS
RD Port
RB7:RB4 pins
Weak
Pull-up
RD Port
Latch
TTL
Input
Buffer
ST
Buffer
RB7:RB6 in Serial Programming Mode
Q3
Q1
Note 1:
I/O pins have diode protection to VDD and VSS.
2:
To enable weak pull-ups, set the appropriate TRIS
bit(s) and clear the RBPU bit (OPTION_REG<7>).
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PIC16F871-I/L 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 33 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
PIC16F871-I/L 制造商:Microchip Technology Inc 功能描述:8BIT FLASH MCU SMD 16F871 PLCC44
PIC16F871-I/P 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 33 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
PIC16F871-I/P 制造商:Microchip Technology Inc 功能描述:IC 8BIT FLASH MCU 16F871 DIP40
PIC16F871-I/PT 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 33 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
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