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How are pins and ports represented in a microcontroller?
Ports are represented by registers inside the microcontroller, and allow the program (firmware) to control the state of the pins, or conversely, read the state of the pins if they are configured as inputs. There is a one-to-one correspondence between the pins on the microcontroller and the bits in its registers.
What to do with unused pins on a microcontroller?
In a typical microcontroller design, it’s normal to end up with some unused pins. These may be general purpose inputs and outputs or pins that are merely labeled as “NC” in the datasheet. The quick and easy solution is to leave these pins unconnected as this means less routing for the hardware as well as less space occupied on the PCB.
How to control multiple outputs in a microcontroller?
If you want discrete analog control over one output at a time, you can use a multiplexer. For digital control over multiple pins, you could use an addressable latchor a shift register. If you need pseudo-analog control over multiple pins, you could use a PWM driver.
How many LEDs can a microcontroller control?
You can control more than one LED per output pin of a microcontroller, even with no other external hardware, using row-column scanning . Even with the 19 pins of an Arduino, this method allows you to control up to 64 LEDs in an 8×8 matrix with a few pins to spare.
How to read the input state of a PIC18 pin?
So PORTCbits.RC6 == 0 should not return correct input state of in RC6 pin. TRISC = 255 should set all pins of PORTC as input. GJ. GJ. On PIC18F4520 and PIC18F4680 you need to configure pins as digital it trough a ADCON1 register instead of ANSELH. Setting a bit to 1 will make a pin digital.
How to control the I / O port on a PIC?
Controlling or driving the I/O port is a pretty easy process. It involves only two consecutive steps. Configure The Pin, determine the data direction, whether it’s an Input or Output Read / Write. If the pin is configured to be an input pin, then you’ll be reading (polling) its state several times within your program.
How is the configuration of a port determined?
The configuration of the port is done via the TRISB and ODCB registers. TRIS states for tri-state, which is a condition where a pin is put into a high impedance state and cannot drive any outputs. The TRISB register determines whether each PORT B pin is an input or output.