Charlie-plexing

[Demon]

Did this a while ago. Don't know if it will help. http://www.picbasic.co.uk/forum/showthread.php?t=14220

If you use the above program you'll need to change you define osc line.

Good luck.

LMAO!

I posted YOUR program above! I googled and searched this forum to try and find where I got it from but never found it.

I'll have to look this over again, I must miss something obvious. You have GPIO, I only see PORT and TRIS registers as relevant on a 16F877.

Robert

[Demon]

Partly fixed.

I was using 3 red, green and yellow LEDs; they have wildly different current draw/voltage drops. I switched to all greens and the ghosting effect is practically gone.

I saw your comments about ghosting and noticed you output PORT before TRIS, didn't help me; tried both ways.

Robert

EDIT:

asm
 __config _HS_OSC & _WDT_OFF & _PWRTE_OFF & _BODEN_ON & _LVP_OFF & _CPD_OFF & _WRT_OFF & _DEBUG_OFF & _CP_OFF
endasm
DEFINE OSC 20
ADCON1 = 7                  ' Set Ports to digital
TRISA = %00000000           ' Set all Ports to output 
TRISB = %00000000
TRISC = %00000000
TRISD = %00000000
TRISE = %00000000
PORTA = %00000000           ' Set ports OFF
PORTB = %00000000
PORTC = %00000000
PORTD = %00000000
PORTE = %00000000
    pause 100
mainloop:
    TRISD = %11111001       ' Enable pins D.1 and 2
    PORTD = %00000100       ' Turn ON pin D.2 --> D.1
    pause 500
    TRISD = %11111001       ' Enable pins D.1 and 2
    PORTD = %00000010       ' Turn ON pin D.1 --> D.2
    pause 500

    TRISD = %11110101       ' Enable pins D.1 and 3
    PORTD = %00001000       ' Turn ON pin D.3 --> D.1
    pause 500
    TRISD = %11110101       ' Enable pins D.1 and 3
    PORTD = %00000010       ' Turn ON pin D.1 --> D.3
    pause 500

    TRISD = %11110011       ' Enable pins D.2 and 3
    PORTD = %00000100       ' Turn ON pin D.2 --> D.3
    pause 500
    TRISD = %11110011       ' Enable pins D.2 and 3
    PORTD = %00001000       ' Turn ON pin D.3 --> D.2
    pause 500

    TRISD = %11111111       ' All pins disabled
    pause 500
    goto mainloop
End

[Boater]

Hi
Looks like I made a wrong post??
Don't know what?

[mpgmike]

On topic, the March 2018 Nuts and Volts Magazine has an article on "Charlieplexing an analog style LED clock", by Robert Gill. It drives 182 LEDs with 14 I/Os.

[Ioannis]

Isn't that impressive?

Ioannis