Pwm & dac

[J. Mark Wolf]

I posted a message yesterday, but it never showed up, so I am posting again. Forgive me if two posts eventually appear.

I have purchased the latest version of PBP to take advantage of some of the newer generation PIC parts, namely the 16F1827, in which I need multiple simultaneous PWM frequencies, and DAC.

Surprisingly, searching for "PWM" and "DAC" turned up no hits on either phrase! I did a search on "16F1827" and got some hits, in which I learned some valable tips on configuring the compiler for this part. Thank you for those posts.

While waiting for my compiler to arrive by mail, can anyone direct me to posts discussing the configuration for two simultaneous discrete PWM frequencies and DAC?

[ScaleRobotics]

This forum has a minimum of 4 characters for its searches. But you can get around that with a google search of the site: http://www.picbasic.co.uk/forum/cont...-for-the-Forum

When you say 2 discrete PWM frequencies, do you really mean sinewave, or just 2 discrete PWM periods? I see page 229 of the datasheet lets you select timer 2,4 or 6 for each of the CCPx pins. Bruce has a DSM example which includes single PWM here: http://www.picbasic.co.uk/forum/show...4268#post84268 using timer2 and PR2. You could use some of the basic PWM code from his example (he's got it mixing pins and such), and set up another with timer4 and PR4.

[J. Mark Wolf]

4 char min search, huh? That explains that!

I don't need sinewaves at all, although that would also work. I really just need just two different simultaneous 50% duty cycle frequencies. As well as DAC, ADC and a little GPIO.

I'll check out Bruces' post.

[Mike, K8LH]

What are the frequencies, please?

[J. Mark Wolf]

What are the frequencies, please?

400Hz, 900Hz, 1600Hz. Only two need to be on at any given time.

I also need to make 1.2Hz through 20Hz (Hz not KHz), for amplitude modulation, which I will do with the DAC.

[Mike, K8LH]

Is the 1.0 to 20.0 Hz signal also a 50% duty cycle square wave? And would it need to be on at the same time as the other two signals?

Mike

<added>

Sorry! Just noticed you said 1.0 to 20.0 Hz signal was going to D/A. So, is that a sine wave output?

[mackrackit]

A little about HPWM for a different chip. DAC.....nothing.
http://www.picbasic.co.uk/forum/showthread.php?t=4672