Allegro A6280 with PICBASIC

[Darrel Taylor]

Great! Glad you got it working.

Besides that, Do I really need to use the Dot Correction?

I guess you don't "really need" to use them. You could just set the current with the REXT resistor, and use the PWM like normal. But if you want to match the brightness of the 3 LED's, then you'll need to set the DOT correction registers.

They Power-up at 36% of the REXT current setting.
So be sure you don't have too much current set-up before trying this. I don't want to blow up your LED's.
But this should set the DOT registers to full current.

Rdot VAR BYTE
Gdot VAR BYTE
Bdot VAR BYTE
Zeros VAR BYTE : Zeros = 0

Rdot = 127  ; Set these to match LED brightness (max 127)
Gdot = 127
Bdot = 127

SetDots:
    funct = 1
    CCP1CON = 0
    shiftout d2pin, c2pin, 1, [funct\1,Zeros\3,Gdot\7,Zeros\3, _
                               Rdot\7,Zeros\3,Bdot\7]
    high latch
    @ NOP
    low latch
    CCP1CON = %00001100
    funct = 0
RETURN

Then just GOSUB SetDots

HTH,

[makson]

Dear Darrel, thanks for the code so I think maybe you're right. The dot correction might not playing a necessary character in here. I still have a question if you don't mind, I'm trying to dim the led by decreasing the value of bvar (let say from 1023 to 0) but no luck. May I know why? Besides that, do u have a complete set of code for this IC's controller for sale? Hope you have a good day.

[Darrel Taylor]

I don't know why it wouldn't, except maybe for the PAUSEs.
The last code posted would take over 42 minutes to dim from 1023 to 0 with the included pauses.

Can you post your code again the way it is now?

[makson]

BVar = 1023

blue:
shiftout d2pin, c2pin,1 [funct\1,Rvar\10,Gvar\10,Bvar\10]
gosub latch
gosub BringUpPWM
pause 100
Bvar = Bvar - 2
if bvar < 3 then goto end
gosub blue

end

I was expecting gradual dimming of the LED, but it pulsates and intensity seems the same.

[Darrel Taylor]

END is a reserved word and can't be used as a label.

The blue loop is GOSUBing back to itself. It should be GOTO.

And, it needs to turn off the CCP module before shifting any data.

Make sure the PAUSE 500 is NOT in the latching: subroutine anymore.

BVar = 1023

blue:
    CCP1CON = 0
    shiftout d2pin, c2pin,1 [funct\1,Rvar\10,Gvar\10,Bvar\10]
    gosub latch
    gosub BringUpPWM
    pause 100
    Bvar = Bvar - 2
    if bvar < 3 then goto BlueDone
GOTO blue

BlueDone:

[makson]

Ok, I'll try the code tomorrow morning as it is too late now. Hope it works, thanks and I'll let you know the result by tomorrow. Thanks

[makson]

BINGO! Darrel, you're the best! Thank you again for the code, now I can dim the LED. Now, the only think in my concern is that when I control too many clusters, the PIC might not be able to store that much of data isn't it? Do you have any recommendation? Hehehe, sorry if I ask too much but really appreciate your help. God bless. Thanks again.

[Darrel Taylor]

Awesome!

Not bad for someone that's never seen that chip before. eh

Well, as far as the memory requirements go. At 6 bytes per cluster (PWM only), you can run an awful lot of clusters with just about any chip. But if it gets to be too many, just throw on a serial FRAM, and you could light up several hundred or thousand clusters, easily.

Well, assuming you had that may pins on your PIC.
Since each cluster needs it's own Latch line, it's kind of limiting.
Of course you could always run the devices in series with a common latch, or add some shift registers to increase the Latch count, but now I'm getting into a whole different area.