On Fri, 21 Aug 2009, Gene Heskett wrote:

> Date: Fri, 21 Aug 2009 21:06:16 -0400
> From: Gene Heskett <gene.hesk...@gmail.com>
> Reply-To: "Enhanced Machine Controller (EMC)"
>     <emc-users@lists.sourceforge.net>
> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net>
> Subject: Re: [Emc-users] Realistic spindle encoder count for parallel port?
> 
> On Friday 21 August 2009, Peter C. Wallace wrote:
>> OK got it done and it fits in XC9572 we have on little CPLD board but I
>> wont be able to test it until Monday
>>
>> 1. Input digital filter
>> ok 15 count filter on a,b,index
>>
>> 2. Quadrature decoder (quadrature to up/down)
>> ok
>>
>> 3. Up down modulo N counter (for divide  by N)
>> ok has 8 selectable DIVIDE_RATIOS via three input signals (jumpers on CPLD
>> bd)
>>
>> 4. 2 bit up/down counter
>> ok
>>
>> 5. 2 bit binary --> quadrature encoder
>> ok
>>
>> 6. Optional index stretcher
>>
>> Works a little strange but should be ok, basically index out is set by
>> incoming (filtered) index and cleared when DIVIDE_RATIO input encoder
>> counts have occured (either up or down or a mix) As long as only one edge
>> is used you will always get a index signal with a minimum width of one
>> (divided) count
>
> That sounds almost exactly like what I would need to control the spindles on
> both my little lathe, and on the micro-mill.  Do you have a target price for
> the completed unit?

I have bare CPLD circuit cards that I can send out for shipping cost, the CPLD 
is about ~2.00 its in a 44 lead PLCC. I could make preprogrammed version if 
anyone wants just chips or just post the source if anyone wants to hack it. 
The source is basically just bits and pieces copy-pasted from the HostMot2 
encoder counter with a few added wigglers and twirlers.

for a standalone chip version I'd add a ring or R/C oscillator so it does not 
need a separate clock

I think I only have one assembled CPLD card An I promised that to Steve B

Peter Wallace
Mesa Electronics

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