PinChange interrupt for ATTiny2313

[Fred Stone]

Hi All,

I'm making a skeeball game for my grandkids and plan to use an ATTiny2313 to read the hole sensors (IR LEDs with IR photosensors) and to display the score on three 7-segment display units. I've been working on a test program to figure out how to implement Pin Change and I think I have it working - sort of. My code triggers an interrupt any time one of the six sensors goes low, and I can see that the interrupt routine is called properly. However, each sensor will have a different scoring value, so it is important that the program knows which sensor triggered the interrupt.

Below is the test code I have come up with for the interrupt routine. It is just a test program, so there aren't any game features in it yet. Also, there's no code to distinguish which sensor triggered the interrupt - that's what I need help with. I would appreciate it if someone could tell me how to read which sensor caused the trigger.

Thanks.

BEGIN CODE:

' =========================================================================================
' Program Name:    Interrupt Test
' Version:         1.0
' Microchip:       ATTiny2313A
' Date:            03-05-15
' Author:          fstone35
' Description:     Tests the PinChange interrupt by temporarily putting a logic-level 0 on
'           one of the interrupt sensor pins.
'
' Wiring:                          
'                       (PA2)  1 |...........| 20  (VCC) 
'                           (PD0)  2 |...........| 19  (PB7) Activity Light
'                           (PD1)  3 |...........| 18  (PB6) Interrupt Light
'                       (PA1)  4 |...........| 17  (PB5) Interrupt sensor 5
'                       (PA0)  5 |...........| 16  (PB4) Interrupt sensor 4
'                           (PD2)  6 |...........| 15  (PB3) Interrupt sensor 3
'                           (PD3)  7 |...........| 14  (PB2) Interrupt sensor 2
'                           (PD4)  8 |...........| 13  (PB1) Interrupt sensor 1
'                           (PD5)  9 |...........| 12  (PB0) Interrupt sensor 0
'                                 GND 10 |...........| 11  (PD6) 
'
' =========================================================================================


#chip tiny2313, 8
#config OSC = OSC_INTOSC_NOCLKOUT, MCLRE = OFF, PWRTE = OFF, CP = OFF WDT = OFF, BOREN = OFF


dir PORTB In        ' Input pins to monitor for interrupt signal. We will use PORTB.0 thru PORTB.5
dir PORTB.6 Out     ' Output pin to display that an interrupt has been generated.
dir PORTB.7 Out     ' Output pin to display activity during non-interrupt cycle.

PORTB.6 = Off
PORTB.7 = Off

' Interrupt settings - This is from studying the datasheet for the ATTiny2313A and a lot of
' trial and error. I'm sure there's a cleaner way to do this, though.
SREG.I = 1      ' Enable Global Interrupt
GIMSK.PCIE = 1      ' Enable Pin Change Interrupt
GIMSK.INT1 = 1      ' Enable External Interrupt Request 0
PCMSK.PCINT5 = 1    ' Enable Pin Change Interrupt for pins PORTB5
PCMSK.PCINT4 = 1    ' Enable Pin Change Interrupt for pins PORTB4
PCMSK.PCINT3 = 1    ' Enable Pin Change Interrupt for pins PORTB3
PCMSK.PCINT2 = 1    ' Enable Pin Change Interrupt for pins PORTB2
PCMSK.PCINT1 = 1    ' Enable Pin Change Interrupt for pins PORTB1
PCMSK.PCINT0 = 1    ' Enable Pin Change Interrupt for pins PORTB0

On Interrupt PinChange Call BlinkMe

Main:
    Do  ' Simple routine just to show that the chip is doing something when there aren't 
        '  any interrupts.
        PORTB.7 = On
        Wait 1 s
            PORTB.7 = Off
        Wait 1 s
    Loop
GoTo Main


Sub BlinkMe ' An interrupt has occurred. Do something...
    PORTB.6 = 1
    Wait 250 ms
    PORTB.6 = 0
    Wait 1 s    ' Don't want another interrupt called too soon, so kill some time before returning.
End Sub

:END CODE

[kent_twt4]

Looks like a fun project! I don't have a ATtiny2313 so speaking in general terms, I would immediately read PortB (or PINB). Then to see which pin is low, rotate the variable and test for carry bit, assign a value due to the bit position.

Dim Score(6)
Score(1) = 50
Score(2) = 100
etc.
...
...
...
sub BlinkMe
WhichPIN = PINB
For Score_Value = 1 to 6
Rotate WhichPIN Right
If SREG.0 On Then
    Add_Value = Score(Score_Value)
End if
Next
New_Score = New_Score + Add_Value
end sub

EDIT: oops...array constants corrected

[Fred Stone]

Thanks for your idea and code. I will try it out and I'll post how it goes. Once I have the real code sorted out I'll post it here in case anyone is interested. Thanks again for your response.