parameters on which PIC is selected

[HenrikOlsson]

Hi,
Another new member and YAIP (Yet Another Inverter Project), here we go again :-)
Take a look at the 18F2431, it will most likely do what you need. It has a PCPWM module with 3 separate (4 for the 18F4431) PWM generators with complementary outputs (up to 6/8 outputs) and deadtime insertion. A fast ADC which can sample two channels simultanously and a boatload of other features.

There are several other devices with 2 (or more) ECCP modules with complementary outputs, use the product selector tool at Microchips website to find them, then look at the datasheet to see if it'll do what you need.

[park21]

hey thanks man
bt the prob is der r gating signals with varying duty cycles evrytim the carrier cuts with the reference signal so how its possible to measure the duty cycle of the signals ,to program accordingly .m attaching snapshot of the matlab simulation result.

[HenrikOlsson]

Hi,
I'm sorry, I have no idea.

[mpgmike]

May I suggest the PIC16F1824 (14-pin) or PIC16F1828 (20-pin) enhanced processors. Get the data sheet, these chips are awesome for what you're wanting to do! First, they include 4 ECCP channels, allow you to invert outputs, PLUS include a cool feature called Data Signal Modulator (DSM) that would allow you to embed your higher frequency within the slow clock, and even PWM that higher frequency while PWM the slow clock.

Hope this helps.
Mike

[park21]

hey thanks man
bt the prob is der r gating signals with varying duty cycles evrytim the carrier cuts with the reference signal so how its possible to measure the duty cycle of the signals ,to program accordingly,hardware point of view .m attaching snapshot of the matlab simulation result.

[mpgmike]

If you have a fixed period (as shown in the above pic), then measure either on-time or off-time with T1G (or T2G, T3G, etc) and subtract it from the total period. Simple math & you have your DC%.

If you have a varying period, use "Toggle Mode" to measure a period, then disable Toggle Mode and set up Single-Shot Mode to measure either on or off time. From there it is once again simple math.

Am I getting closer?

Mike

[richard]

try this

move1:
Lbyte = (position1 & %00001111) 'servo 0 + lownib
Hbyte = %10000000 |( (position1 & %11110000)>>4) 'servo 0 + highnib
SEROUT2 serial_out,baud1,[Lbyte,Hbyte] 'send command to FT639
PAUSE 100
RETURN

edit oops wrong thread

[park21]

hi mike
gt ur point,so ur saying taking the reference and carrier signal (20khz) frm ADC n checking for its on and off time??
cos if you c ma reference its a absolute and i dnt have my negative cycle.so how do i generate my ref n carrier 1st??
i'am thinking of taking in signals from ADC and den comparing...
m i right??

[park21]

CCPxM3:CCPxM0 (CCPxCON<3:0>) to capture every rising edge of the waveform ??if m considering 18f4431 ...