Overview Of PortB and its associate's
PortB of PIC16F887 is a bi-directional digital I/O. PORTB is its I/O register. It's an 8-bit read/write register.The corresponding directional control of PORTB is TRISB (PORTB Tri-State Register) register. Clearing this register to make an output port.
00:00 / 00:00
The weak pull up resistors built inside the MCU could be individually turning on by software setting. The WPUB (Weak Pull-Up PORTB Register) turn on and off the internal resistor of PORTB individually.
The RBPU (PortB Pull-up Enable) bit of the OPTION register is the global switch of WPUB. Clearing this bit to enable this feature.
Programming in MikroC
In this example, I use the lower nibble of PORTB as a digital input. This nibble is turned on high by its internal weak pull up resistor configured in software.
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Schematic Diagram |
The lower nibble is an input to the higher nibble that connect to four LED(s).
void main() { PORTB=0x00; // Clear portb TRISB=0x0F; // RB0-RB3 input RB4-RB7 output ANSELH=0x00; // Disable Analog Function OPTION_REG.NOT_RBPU=0; // Enable weak pullups on portb WPUB=0x0F; // Enable Weak pullups on RB0:RB3 while(1) PORTB=PORTB<<4; // Shift left 4 times }
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