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#1 2010-03-21 09:11:18

New member

Interfacing external circuits and devices


Good idea for the "demo bench source code", but i'm more computer specialist that electronic specialist ! Could you also send some electronic schematic for these external circuits ?

Thank's a lot



#2 2010-03-24 10:57:00


Re: Interfacing external circuits and devices

The only external circuit that I use is a Low Pass Filter. I need it to use the PWM ports as a DAC converter.

You need:

560 ohm resistor
4.7 Kohm trimmer
2.2 uF capacitor

You will have a 30 to 300Hz variable filter.

-connect the 560 ohm resistor to a pin of your choice: 9th, 10th, 11th or 12th pin of uChameleon

-connect the central pin of the trimmer to the resistor

-create a short circuit from the central pin to another one of the trimmer

-use the last free trimmer pin as the output of the filter

-connect the capacitor between the output and ground

code wrote:

use this code for pin 9:

pwm 9 period 200
pwm 9 width 0
pwm on

after the init pin code, use:
pwm 9 width 0
pwm 9 width 100
pwm 9 width 200
to understand with a multimeter on the output how to use this feature
you will have 0 volt, 2.4 volt, 4.8 volt
(I cant reach 5 volt)

ST7FLite39 daughter board
REva 2.10
RLink 3.4
"uChameleon" as: SPI Master for debug, Analog output for sensing emulation



#3 2010-03-24 12:20:31

New member

Re: Interfacing external circuits and devices

Nice !
I will try this as soon as possible

You could see my realisation here :
and the blog :



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