Microcontroller inputs in C language? Answered

We need a little more info. It's unclear what you're attempting here. And I won't be much help with programming the 8051. I assume the MCT-8051 is this.

You're setting up a data transfer. What direction? (from the AVR to the 8051? or the other way?)

Or is it a bidirectional transfer? That can't be answered simply, since you're describing a "protocol."

If the 8051 port is set for output, how can it be a "sensor?" And how can an "input" in the butterfly control an LED on the MCT-8051? Seems like your data directions are opposite...

#define FIREBUTTON	PB7// initialize registersDDRB &= ~_BV(DDB7);        // clear bit, input fire-buttonPORTB |= _BV(FIREBUTTON);  // set bit, enable pull-up resistor// read the pinif(!(PINB & _BV(FIREBUTTON))){	delay_ms(50);	// debouncing, of a sort...        if(!(PINB & _BV(FIREBUTTON)))        {        // do something here        }}

When i tryed your code, it gaved a error on your &= and l= sections. Have any idea why?

Sorry, I didn't see your request for an example earlier.... I could throw something together--the above code was adapted from an atmega8, but it is reusing one of the ISP pins on the 2313, which isn't ideal....Something simple for the 2313 won't be too difficult. Without seeing your code (or the error msg), I can't be sure about the error. Maybe you used the statements outside of a function? (main() or other function...) The define statement is fine outside, but not the init code... Also, can you tell us a bit more about your setup? C compiler? (assuming avrgcc) and programmer?

I'm sorry i did some research and found help on it. I'm good now.
http://www.avrtutor.com/tutorial/thermo/ioports.php

I use AVRDUDE

/*********************************************AVR button test, 2313*********************************************/#include <avr/io.h>#include <inttypes.h>#define F_CPU 1000000UL  	// 1 MHz#include <util/delay.h>#define BUTTON	    PD4 // button#define LED         PB1 // LED outputvoid delay_ms(unsigned int ms)/* delay for a minimum of <ms> */{	// calibrated delay.	while(ms){		_delay_ms(0.96);		ms--;	}}int main(void){    /* INITIALIZE */	    DDRD &= ~_BV(DDD4);	// clear bit, input fire-button    PORTD |= _BV(BUTTON); // set bit, enable pull-up resistor    DDRB |= _BV(DDB1);	// set bit for output    PORTB |= _BV(LED);	// set bit, off	// infinite loop	while(1) {        if(!(PIND & _BV(BUTTON)))        {        	// blink			PORTB &= ~_BV(LED);	// turn on LED			delay_ms(50);		    // wait			PORTB |= _BV(LED);	    // turn it off			delay_ms(100);        }    }	return(0);}

Oh, and since it's using internal pullups--the button (when closed) is connected to GND (not VCC...)

I'm a noob for i'm just starting this. recently i've been messing with beeps and sounds also. Can you please give me a full code example? like a simple: Button on pin PD4, LED on PB1... when button is pushed, led lights. Would like if you could!

gmoon looks like he's got more recent experience with AVR than I, since I missed the PINB vs PORTB issue. I had also assumed that you already knew about changing pin direction since you were already outputting to pins, and the default power-up state is that pins are INPUTs.