68300

Melear Charles-rdph40 wrote:

> Now Roy,
>
> I think you should be a little more careful here.  In the last line of your email, you said that any advice would be welcome.
>
> That sure opens a fairly wide window.
>
> Yes, indeed, when you are running the PMM/PMA - PSP - ITC function, you only pass a 24 bit parameter.  There is PPWA_Lower_Word and PPWA_Upper_Byte.  You DO NOT get 32-bit resolution here, you get 24-bit resolution.
>
> I know a guy that has written a fairly good algorithm on the missing / additional tooth and I can turn you on to him if you like.
>
> Regards,
>
> Charlie
>
> -----Original Message-----
> From: Roy [mailto:spectric@...]
> Sent: Wednesday, May 08, 2002 6:02 AM
> To: 68300@yahoogroups.com
> Subject: [68300] TPU problems
>
> Hi all
>
> I am having nightmares getting the TPU to function.
>
> In my current project I am running a 68376 at 25 Mhz,
>    W = 1, X = 1 & Y = 24.
>
> >From this I have worked out that the TPU TCR1
> frequency will be 6.3 Mhz if PSCK = 1 & TCR1 = 1,
> giving me a Period of 160 Ns.
>
> The TPU functions I am running are ITC channel 0, PMA
> channel 1 and PSP on channels 2,3,4,5,6 & 7.
>
> In my application I have 12 teeth on a sensor wheel
> which equates to a spacing of 30? and at 500 RPM
> which is the lowest rotational speed the time between
> teeth is 10 Ms.
>
> This gives 62,500 TCR1 counts between teeth, ( 10 Ms /
> 160Ns ).
>
> Now the Motorola literature states that the TPU
> measures this period to a 23 bit resolution,
> so is the max count 65,536 or 8,388,608 ?
>
> If it is 23 bit then why only pass a 16 bit parameter
> " PERIOD LOW WORD " to functions runing PSP ?
>
> My other question is the ERROR bit in the PMA
> function, what is it's address ?  All other parameters
> have
> the format of 00FFFF channel number parameter number,
> in my application I have taken it as being FFFF16.
>
> All suggestions and advice welcomed
>
>             thanks Roy
>
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From what I can see, this group move to Yahoo has been a success. I didn't get any spam, and aside from the new E-mail address, it's the same.

John Donoghue
jdsb@...