We are trying to get the following code to work on a ATTiny2313. As mentioned, it works on an UNO. This project is high volume and price sensitive, so a display chip is not going to be within budget. Thank you !
/* 3 digit 7 segments LED count up
Display 3 digit 7 segment LED and count up perpetual
to demonstrate multiplexing of LED in software.
Further explanation in
https://kositapan.wordpress.com/2014/03/01/multiplexing-4-digit-led-with-arduino
*/
const int ledPin = 13; // blink onboard LED to test multi tasking
const int nbrDigits = 3; // this is 3 digit LED
// mapping segment DP,G,F,E,D,C,B,A data pin
const int segmentPins[8] = { 7,6,5,4,3,2,1,0 };
// mapping digit 1,2,3 data pin, skip pin 13 on board LED
const int digitPins[nbrDigits] = { 8,9,10 };
// 7 segment pattern from 0-9, last bit is DP - don't use
const byte numeral[10] = { //ABCDEFG /dp
B11111100, // 0
B01100000, // 1
B11011010, // 2
B11110010, // 3
B01100110, // 4
B10110110, // 5
B10111110, // 6
B11100000, // 7
B11111110, // 8
B11110110, // 9
};
// internal buffer of digit 1,2,3 initial is 10 (blank)
static int valueDigit[nbrDigits] = { 10, 10, 10,};
int ledState = LOW; // onboard LED blink state
// the follow variables is a long because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
const long interval = 1000; // interval to blink onboard LED (milliseconds)
const long intervalCountUp = 200; // 100 interval to count up number (milliseconds)
unsigned long lastCountUpMillis = millis();
unsigned long lastBlinkMillis = millis();
static int currentNumber = 000; // arbitary initial LED number
void setup() {
// set the digital pin as output:
pinMode(ledPin, OUTPUT);
for (int i=0; i<8; i++)
pinMode(segmentPins[i], OUTPUT);
for (int i=0; i<nbrDigits; i++)
pinMode(digitPins[i], OUTPUT);
// Serial.begin(9600);
}
// ShowDigit: physical display one digit of LED
// This function should be optimized since it is called all the time
void showDigit(int number, int digit) {
boolean isBitSet;
// turn off all digit before write anything
// to minimize flicker
for (int i=0; i<nbrDigits; i++)
digitalWrite(digitPins[i], LOW);
// write segment bit accordingly
for (int segment=0; segment<8; segment++) {
if (number<0||number>9)
isBitSet = 0;
else
isBitSet = bitRead(numeral[number], segment);
digitalWrite(segmentPins[segment], isBitSet);
}
// now turn on particular digit
digitalWrite(digitPins[digit], HIGH);
}
// refreshLED: main dispatch for LED multi digit multiplexing
// this version just serialize each digit display
// future version should optimize delay execution until each digit has
// display time of 100Hz to minimize CPU usage
void refreshLED() {
static int lastDigit = 0;
if (++lastDigit > nbrDigits)
lastDigit = 0;
showDigit(valueDigit[lastDigit], lastDigit);
}
// showDecimal convert decimal and stored result in LED buffer format
// this function do not display anything
// the refreshLED will actually display LED buffer
void showDecimal(int number) {
// negative mean blank all digit
if (number<0) { for (int d=(nbrDigits-1); d>=0; d--) {
valueDigit[d] = 10; // 10 is interpret as blank digit
}
return;
}
for (int d=(nbrDigits-1); d>=0; d--) {
if (number > 0) {
valueDigit[d] = number%10;
number = number / 10;
}
else valueDigit[d] = 10;
}
}
void loop()
{
unsigned long now = millis();
// here is where you'd put code that needs to be running all the time.
refreshLED();
// check to see if it's time to count up 7 segment LED
if (now - lastCountUpMillis > intervalCountUp) {
currentNumber++;
showDecimal(currentNumber);
lastCountUpMillis += intervalCountUp;
}
// check to see if it's time to blink onboard LED
if (now - lastBlinkMillis > interval) {
// if the LED is off turn it on and vice-versa:
if (ledState == LOW)
ledState = HIGH;
else
ledState = LOW;
// set the LED with the ledState of the variable:
digitalWrite(ledPin, ledState);
lastBlinkMillis += interval;
}
}
