On Tue, 16 Feb 2010, claude wrote:
> Date: Tue, 16 Feb 2010 21:13:26 +0100
> From: claude <[email protected]>
> Reply-To: "Enhanced Machine Controller (EMC)"
> <[email protected]>
> To: [email protected]
> Subject: [Emc-users] hostmot2 PWM
>
> Hi all,
>
> First, I take this opportunity to say a big THANKS to every one for this
> wonderful piece of software. I use it for machining and also some
> automatic machine with great reliability and flexibility.
>
>
> I may use for a future project some MESA card with hostmot2 "firmware".
> After reading a bit how to set PWM, I don't get the complete picture,
> what is PDM PWM ? what is the difference between this and "regular" PWM
> ? is there somewhere drawing on how it work (I look a bit on VHDL code,
> but it pretty difficult to get the exact way of work).
PWM and PDM are similar in that they both let you set the duty-cycle of
a digital signal (the 'on' time versus total cycle time) But they differ in
their actual generated waveforms.
For example a 12 bit PWM signal with 50% duty cycle would be on for
2048 clocks and off for 2048 clocks. If the PWM clock was 100 MHz, this would
give a ~24.4 KHz square wave.
A 12 bit PDM signal with 50% duty cycle would alternate on-off at each
clock. With a 100 MHz clock this would result in a 50 MHz square wave. Both
modes let you set the duty cycle but the output waveforms are different.
PWM is suitable for driving HBridges, but is harder to filter than PDM
if analog output is desired.
>
> As a second point, I may do some change to the PWM VDHL code. I didn't
> find any explanation on how to compile FPGA (I have knowledge on FPGA
> and VHDL language, unfortunately only on Altera one). As much as I
> imagine, there should be some free way to do compilation and test, but
> this doesn't seems to be integrated with EMC distribution, can someone
> give me some hint ??
There are free (as in beer) tools for compilation available from Xilinx:
Xilinx WebPack
>
> regards
>
> Claude
>
>
>
>
Peter Wallace
Mesa Electronics
(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.
------------------------------------------------------------------------------
SOLARIS 10 is the OS for Data Centers - provides features such as DTrace,
Predictive Self Healing and Award Winning ZFS. Get Solaris 10 NOW
http://p.sf.net/sfu/solaris-dev2dev
_______________________________________________
Emc-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-users
