Bit Angle Modulation (BAM) in a PIC

[RadikalQ3]

RadikalQ3,
Thanks for the Mirror Image idea!
It has completely removed the blinking problem.

Oh, it's nothing... just was an idea.
I have spent the last days reading all I found in internet about PWM, BAM, Frecuency Modulation, etc.
I have a project to do and I am gathering all the information about this topic.
Simply... I found your topic (and this forum) and I thought that was a nice challenge solve your blinking problem O
I am waiting the recepcion of some hardware and in a few days I can do test with this for my own.

Later, I realized that this is a forum on basic! (and I just use assembler)

[Darrel Taylor]

Videos of oscilloscopes never seem to work very well.
But it's interesting to watch the way the mirror image works.

Let's call it BAM-BAM.

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/4eZho2fN3r8&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/4eZho2fN3r8&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>

It's going through a ramp from 0-255 and back down.

[Ioannis]

Hi Darrel. It looks very good! Congratulations on that!

Very good job.

Ioannis

[JEC]

I'd run in to the exact same issues between 127 and 128. Never had time to investigate it further.

My implementation just used a state machine in the interrupt routine - 1 state for each bit.

Each state sets TMR1 to a different level, then sets / clears the appropriate pins.

I assume that you're implementing the 2xF 'mirror' method in a similar way? Very clever.

[Darrel Taylor]

Hi Ioannis

Hi John,
&nbsp; Just yesterday I was thinking about how this might be good for your Christmas Lights.
&nbsp; Apparently, the thought had not escaped you.

I assume that you're implementing the 2xF 'mirror' method in a similar way?

Well, the best method, is still to be determined. I'm trying every way I can think of ...

Currently, I'm rotating the DutyCycle out to the Pin, and when rotating it left, I shift the timer value Right to give 1/2 the period for the next bit, when rotating right, the timerval gets shifted left for 2x the period.

I'm also trying to incorporate the "Cylon Scanner" that Bruce and I were playing with last year.
With the mirror image, the bit's are scanned back and forth much like a Cylon (or Kitt the car).

Never thought that optimization exercise would actually be useful some day.
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[JEC]

&nbsp; Just yesterday I was thinking about how this might be good for your Christmas Lights.
&nbsp; Apparently, the thought had not escaped you.

Pity the 10F doesn't have a TMR1...

[RadikalQ3]

Let's call it BAM-BAM.

Better... BAM-MAB

[Darrel Taylor]

Better... BAM-MAB

I had thought of that ... but it was too hard to say (unless you're drunk).
Besides, I thought maybe Pebbles would show up to see what BamBam was doing.

Progress is cranking.
Should have an update soon.
<br>

[mister_e]

Should be BAMAB... unless your program stick too much on a side of the PWM cycle ;o)

[bcd]

I played with BAM some time ago, but always found this step in the middle of the range to be its big issue. Thank you for a workable solution !!!

Its interesting that Artistic License (the inventor, or populariser of BAM) make no mention of this issue.

Bill.

[Darrel Taylor]

Its interesting that Artistic License (the inventor, or populariser of BAM) make no mention of this issue.

I think Artistic License had given up on it, since all mention of BAM has been removed from their website. And when I was searching the web for answers, all I found was lots of threads with people complaining of blinking problems.

BAM-BAM to the rescue!
<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=3147&stc=1&d=123283468 8" /> <!-- -->

I now have working code.
Anyone want to beta test it before I make it public?

It can run up to 48 LEDs simultaniously. (48mhz OSC)
Or 1 LED per mhz. 4mhz=4 LEDs, 20mhz=20 LEDs.
It has a self-contained Interrupt system. Instant Interrupts not required.
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