Multy frequency generator

Archiver

I need a code for my Basic stamp II which gives constantly at same
time, to separate pins, 4 frequencies (1Hz, 4Hz 11,04Hz and 13,06Hz).
Is it possible? If it is, can you help me?

Archiver

The Stamp generally does one thing at a time, so this will be hard to do
reliably. You can generate multiple frequencies by "manually" changing the
output lines, but the frequency is pretty low. For example:

i=0
loopx:
i=i+1
toggle 0
if i//2=0 then loopx
toggle 1
goto loopx

However, the adjustment of the frequency is rather crude.

Have you considered a PAK-VIII? With the prescaler, you should be able to
generate your frequencies (periods of 1s, 250mS, 90.6mS, and 76.6mS). If you
wanted 50% duty cycle, you'd set the on and off times for each channel equal
(500mS, 125mS, 45.3mS, and 38.3mS).

With the default prescaler (10uS) this works out to:
50000, 12500, 4530, and 3830 -- the values are 16-bit, so 50000 is in range.
You can also adjust the prescaler to get a wider range, at the expense of
resolution, of course. You might need to do this if you wanted a duty cycle
other than 50% since a 1S period is very close to the slowest the PAK can go
without additional prescaling. For example, say you wanted a 10% duty cycle.
You'd need 10000 and 90000. 90000 is too big. But if you set the prescaler
to 20uS, you could go with 5000 and 45000 -- in range.

In addition to generating pulses, the PAK can stop after a certain count of
pulses. You can also force any line high, low, or high impedance (so you can
use spare pins for basic digital output functions). You can use it to
generate pulses to control servos, PWM, tones, etc. The minimum prescale is
5uS, but this wouldn't work for your application. Also, at 5uS you can only
use 4 channels for pulse output.

Hope that helps.

Regards,

Al Williams
AWC
* Basic Stamp FAQ: http://www.al-williams.com/wd5gnr/stampfaq.htm


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Original Message

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> From: ska@f... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=8A-HqQrXMGgT8g1NSRfHeqTDOdEMg-QRfcE58j3X3_ToSA42n-WZNkZ4xgidwuLBpF5nl0fo]ska@f...[/url
> Sent: Friday, July 14, 2000 6:27 AM
> To: basicstamps@egroups.com
> Subject: [noparse][[/noparse]basicstamps] Multy frequency generator
>
>
> I need a code for my Basic stamp II which gives constantly at same
> time, to separate pins, 4 frequencies (1Hz, 4Hz 11,04Hz and 13,06Hz).
> Is it possible? If it is, can you help me?
>
>
>
>