I'm currently trying to connect a 7×5 dot matrix to an AVR ATMega328p. I'm already using port B/D and I would like to use port C so that I have extra output pins. My question is, can I use port C as digital output pins without ruining the microcontroller? I know that this port is normally used for analog-digital conversion. If so, do I need to add additional configurations inside my C program?
Electronic – AVR atmega328p – Can I use port C as digital output pins
atmega328pavravr-gcc
Related Solutions
intcan only be 0-255
That's not correct. In the C programming language, an int is always at least 16 bits wide, even on 8-bit micros. A char is 8 bits wide.
But when using inttypes.h, I strongly recommend using the explicit types like uint8_t,int16_t or uint32_t.
Your real error is using _delay_ms() with a variable parameter. This is not allowed, as it is a macro involving floating point calculations - at least in avr gcc. You are supposed to use something like this:
void DelayMs(int delay) {
while(delay--) _delay_ms(1);
}
The two output pins (2,3) are open collector NPN transistors. These will be switched on and off at a rate that sets the speed of the fan. So your guess is correct.
Coils can produce some spiky voltages so I wouldn't recommend directly connecting these pins to the input of a microcontroller. A simple resistor/transistor should do.
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Best Answer
Yes you can.
Below table describes about Sink and source capabilities: VOH is when you try to output a high signal. The current should be less than a particular value which you can find in the same table. VOL is when you output a logic zero. Microcontroller can sink current and you should also care about limiting the current. Excess current may lead to damage of the IO Pin or the whole MCU.
Below are some notes about the analog function rich port C (in some packages, other ports) describing the GPIO capabilities and precautions to be taken.
Follow the normal routine as configuring other pins.