Since it's 8 bit with relatively slow sine waves, I suspect you can pick
any of the microchip devices and make it work.  I suspect that one of
the 12c5xx devices would fit the bill both in size and power consumption
if you paired it with a fast crystal.

Development, however, would go much faster on a flash based pic.  Using
an 18f part would still be small, low power, and provide many more
options for future projects and development.  I've never used a
ready-made development board or kit, so I can't suggest any one in
particular.  I've been well served by breadboards and a PicStart +
programmer.

A part with 3 timers that trigger interrupts and a PWM output (which
will use a seperate timer) would make your job easier.

Then set up a small table that holds 1/4 of a sine wave.  The software
needs to set up the timers and PWM, then it simply responds to the
interrupts for each timer, recalculates the output value, and sets the
pwm output.

I have no idea what you mean by 'small fee' but if you really want a
ready-made solution I charge $60/hr and expect this type of project to
take 4-6 hours.  At that price, though, you could buy quite a bit of
equipment and do it yourself.  The first time is always the hardest, but
it can be rewarding.  I'd suggest an ICD-2, a bunch of chips and parts,
breadboard, and a cheap power supply.

-Adam

nielsenp@IPRIMUS.COM.AU wrote:

>As a novice, I have tried several approaches to get this going.
>
>No one seems too eager to take on my relatively small project for a small
>fee, and I have been unable to find a ready-made design. So, for a learner
>with primarily analog experience, what is the most direct route to PIC
>signal generation apps like the following.
>
>To produce simultaneously 3 sinewaves of differing amplitude and frequency
>(between 0.1 and 100Hz) at 8 bit res. One SW will always sit at max
>available swing.
>
>Desired values for both parameters above are to be entered by myself at
>program stage (ideally). Increments of 0.1Hz and 0.03 volts (assuming 3V
>operation) are preferred for this. I can be a bit flexible according to the
>most straightforward maths.
>
>Above SW's are then summed to one output. Each is to be capable of being
>independently disabled via external link. I suppose 3 separately pinned
>outputs could be _externally_ summed, level trimmed, and switched if this
>is all I can manage in the next few months.
>
>Overall output level is to be compatible with op amp input. Circuit to run
>on 4 x "AAA" batteries. Micro looks at battery voltage and lights LED when
>low. The device needs to be portable and stand-alone, so that let's out
>PC's. I also need about a dozen for my university field work.
>
>There are a few similar but related projects I am also interested in doing,
>so continually out-sourcing design work is not an economical option.
>
>Thus far, I have found only strings of partially suitable code online, and
>a couple of relatively expensive learning kits, such as Brunning's, that
>offer a sine generation project as part of the manual.
>
>What is the most efficient PIC (or Atmel) to use? Where is my closest
>starting point, kit, code library, etc. in terms of a hands-on learning
>experience? BTW I am not interested in control apps, but I wish I were
>because EVERYONE seems to be doing this.
>
>Or ... has anyone seen or done anything that will fit the bill, more or
>less as is? And, of course, I would still be willing to pay someone
>something for the working code.
>
>Any suggestions much appreciated.
>
>Peter Nielsen
>
>--
>http://www.piclist.com hint: To leave the PICList
>mailto:piclist-unsubscribe-request@mitvma.mit.edu
>
>
>
>
>

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu