xMega PWM question

techknight · Joined: 21 Apr 2008 Posts: 231

With the 74HC595, the output enable is inverse logic. Active low.

Now, the problem with this is, it makes the PWM CCA backwards on the timer. So, is there a way to fix it in the xmega? I know I could do it in the Megas with changing a parameter or two in the config timer.

any ideas without throwing an inverter in there? thanks.

(BASCOM-AVR version : 2.0.7.8 )

JC · Joined: 15 Dec 2007 Posts: 586 Location: Cleveland, OH

Which Xmega?

I thought the Xmegas had a register to invert the output signal, as one of the last stages of the digital I/O pin driver hardware.

It is obviously much easier to set a Register bit than it is to add additional hardware.

JC

techknight · Joined: 21 Apr 2008 Posts: 231

Well, I dont know if it does or not.

techknight · Joined: 21 Apr 2008 Posts: 231

I am also having another problem.

If I set the TCC0_CCA value right after initializing the timer for the first time, it works fine.

But in the middle of the program, no matter what I do, if I set TCC0_CCA again, I lose the PWM completely.

any ideas?

Edit: I figured it out. it seems to repeat every 256 even though its a 16-bit mode pwm.... odd.

techknight · Joined: 21 Apr 2008 Posts: 231

New problem: PORTC.4 isnt working! Ive scoured the datasheet to see a reason why, and I am coming up empty.

But for the life of me, if I set PORTC.4 = output, and try working with PORTC.4, it does not function. Strange.

Meister · Joined: 27 May 2010 Posts: 319

Code, please.