char keypad_matrix()
{
//Serial.println(“keypad_matrix”);
if(Serial3.available())
{
char result = Serial3.read();//Read key press
return result;
}
else
{
return ‘ ‘;//equivalent to -1, a null result
}
//delay(10);
}
This code polls for keypresses. If it returns anything then the keypresses are acted on. Stuff like this is why it is so important to keep the code looping and not blocking. If there are multiple keypresses buffered this will grab one and leave the rest for next loop.
void enter_pin(char c)
{
//Serial.print(“Pin Button = “);
//Serial.println(reader2);
LCD_disp(“*”);
pin[digit] = c – ‘0’;//stores as numbers rather than characters
digit++;
}
Here is how a pin is incremented, it is one of the few places I do not overwrite the entire LCD line at once.
void backspace_pin()
{
pin[digit] = 15;
//Serial.println(“backspace”);
LCD_displn(” “,1);
LCD_displn(“Pin:”,1);
if(digit >0)
{
digit–;
pin[digit] = 15;
}
for (int i = 0;i<digit;i++)//repopulates asterisks
{
LCD_disp(“*”);
}
//for(int i=0;i<(sizeof(pin)/sizeof(pin[0]));i++)
//{
// Serial.print(pin[i]);
//}
}
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Removing a digit is tricky, I have to set it to an impossible to type character and rewrite the line of asterisks because I don’t support arbitrary cursor positioning.
void clear_pin()
{
digit = 0;
for(int i=0;i<(sizeof(pin)/sizeof(pin[0]));i++)
{
pin[i] = 15;
}
}
Clearing a pin is easy, set back to unprintable. These steps are done in the key taking process which is longer and in the main logic code. This is part of the greater OpenAccess project.
