Allegro A6280 with PICBASIC

[makson]

Dear Darrel, sorry for the trouble again, below is the code that I'm trying to work with but it doesn't light up the led as expected. Please kindly advise. Thanks in advance.

@ DEVICE HS_OSC
DEFINE OSC 4
include "bs1defs.bas"

CMCON = 7 ' PortA = digital I/O
VRCON = 0 ' A/D Voltage reference disabled
TRISB = %00000000 ' B.3=PWM,B.0,B.1,B.2 blink LEDs
PR2 = 25 ' Set PWM for approximately 38KHz
CCPR1L = 13 ' Set PWM Duty-Cycle to 50%
CCP1CON = %00001100 ' Mode select = PWM
T2CON = %00000100 ' Timer2 ON + 1:1 prescale

d2pin var portb.0
c2pin var portb.3
latch var portb.4
'oe var portb.1


funct var byte
rvar var word
gvar var word
bvar var word

funct = 0
gvar = %0011111111
rvar = %0000000000
bvar = %0000000000

begin:
high porta.0
pause 1000
low porta.0

CCPR1L = 0
shiftout d2pin, c2pin, 1, [funct\1,gvar\10,rvar\10,bvar\10]
gosub latching

pause 1000
gosub bringpwm


goto begin




bringpwm:
PR2 = 25 ' Set PWM for approximately 38KHz
CCPR1L = 13 ' Set PWM Duty-Cycle to 50%
CCP1CON = %00001100 ' Mode select = PWM
T2CON = %00000100 ' Timer2 ON + 1:1 prescale
return

latching:
high latch
pause 500

low latch
return

[Darrel Taylor]

Putting 0 in CCPR1L just stops the output with a 0% duty cycle. The pin is still controlled by the CCP module.

CCP1CON = 0   Will allow SHIFTOUT to use the PIN.

And for 100Khz, use PR2 = 9 and CCPR1L = 5.

[makson]

Dear Darrel,

Thanks to you. The code running well now. I can turn the color from Red to green and to blue. You are really good. Thanks again. But now, the story continue...... I need to know how to use the Dot Correction because I don't really understand the concept. Besides that, Do I really need to use the Dot Correction? Please kindly advise.

[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.