Re: Didactic Quality of Datasheets (Texas Timers)

From: Clark G. Smith (clarkgsmith_at_comcast.net)
Date: 05/08/04 

Date: Sat, 8 May 2004 02:04:15 -0400

Ok Janvi, I don't have time to read all that ***, but I understand you
complaint, I think. My most recent project was on a DM642 DSP, which is
where I understood, TI has the, without any doubt, worst god-damned
technical documentation of anybody in the world. Its like they have a
theory, lets take the information, spread it over as many documents as
possible (all *.pdf, none printed), make that practically unuseable, and
give it to our customers.......... Maybe a note to TI........... that
DM642 is probably the baddest-ass processing chip on the planet (ethernet
and everything) but you have to support the son-of-a-bitch.......... and
part of "support" means comprehensive documentation.........

"Janvi" <janvi@despammed.com> wrote in message
news:pan.2004.05.07.14.04.39.809898.2127@despammed.com...
> Already walked through a dozend of diffrent uC Architectures Zilog,
> Motorola, Infineon, STM, AMD and more in the recent years.
> But for the moment the Texas Instruments TMS320C24x Peripheral
> description drives me crazy.
>
> The Texas data*** consists of a mix of feature lists and examples some
> diagramms and some descriptions. Everything shaked and then printed.
>
> There are 3 Timers. Only Timer 2&3 can be cascaded. Each timer has
> its own compare function but there are also 3 full compare units and
> 3 simple compare units. But later you read, that full compare is
> only possible for timer1 and simple compare is only possible for timer
> 1 and 2. Full compare outputs are inverted and non inverted with
> additional dead band support for push pull amplifiers while simple
> compare units have only one output pin. Becouse the simple compare
> output pin is diffrent from the full compare outputs, there is a total
> of 9 output pins for 3 timers. Maybe I start being to old
> to learn new things but for those 3 timers I had to read 100 pages !!!
> (chapter2) and when I am through I have to start again becouse I
> did not understand anything and have no overview above the possible
> functions.
>
> Maybe things are complex but the more complex something is, the more
> care should be taken on how to divide the chapters. Good diagrams can
> say more than 1000 words. The writers for datasheets may be good chip
> designers but sometimes I doubt they already heard anything from
> didactic skills.
>
> But maybe there are some Texas Counter specialists here:
>
> My Timer 2 is connected to an encoder. This works already well
> counting up and down with the axis. Only forward direction important.
> At a specific angle, a magnet valve should be switched on
> and at another angle it shoud be switched off again. The
> rising edge current for the magnet valve should be an initial pulse
> with variable length. Therefore timer 3 can possibly provide a
> time reference. After that, a hold current limited by PWM should
> be applied to the valve. Therefore timer 1 provides a PWM base
> freqency (approx 5-10 khz) and variable width. Cannot use the
> simple compare outputs becouse this would require a HW change in
> the design. Timer 3 currently makes a countdown interrupt for system
> time tic interrupt.
>
> How to setup the Action Controll Registers and what is the best
> output pin? This task requires 2 timer outputs one for initial pulse
> and one for PWM connected by wired or? Can I achieve HW action accuracy
> for the initial pulse, pulse length and PWM stop position or time or do
> I have to use Interrupt Service to enable disable the PWM outputs?