UFF. connected with a 220n. Nothing.

> From: jack.monegato@hotmail.it
> To: piclist@mit.edu
> Subject: RE: [PIC]PIC18F2550A, Pwm doesn't work when using on external po=
wer	supply
> Date: Mon, 26 Sep 2011 20:26:15 +0200
>=20
>=20
>=20
> I think i found the problem. I didn't realize i had to put a capacitor be=
tween Vusb and Vss, even if i didn't use USB.
>=20
>=20
> > From: jack.monegato@hotmail.it
> > To: piclist@mit.edu
> > Subject: [PIC]PIC18F2550A, Pwm doesn't work when using on external powe=
r supply
> > Date: Mon, 26 Sep 2011 18:57:02 +0200
> >=20
> >=20
> > Hello there,
> > I have quite a big problem. I am building a sound synthesizer using a 1=
8F2550 as tri/sqr wave generator. Wrote the program, tested on breadboard, =
transfered to board, tested on board (with PICkit 2)... everything just PER=
FECT.
> >=20
> > I also built a 12 to 9 to 5 V power supply by putting in series a 7809 =
then a 7805, it works, the voltages are what they should be (9V is for the =
analog part of the circuit), I can hear the square wave but not the triangu=
lar (from PWM output). PWM seems not to work. but if i touch to some random=
 and unconnected parts (i.e., the sixth pin in the programmer dock) I can h=
ear, at lower than expected frequency, another square wave, from the pwm ou=
tput. Then if i unplug the external supply and plug in the PICkit i have to=
 turn on then turn off then turn on and ONLY after that the pic start worki=
ng properly again.
> >=20
> > Unfortunately i don't have any measurement tool but a multimeter and a =
steinberg sound card (as sound analyzer). The voltmeter dysplays 4.62V when=
 with PICkit and 5.02V when power supply
> >=20
> > Any suggestion? I already changed a couple of capacitors in the supply =
ciruit, but nothing changed. the circuit is:
> >=20
> >                        ______           |->+9V       ______
> > 12VDC --+------+------| 7809 |---+------+-----+-----| 7805 |---+------+=
----> +5V
> >         |      |      |______|   |      |      |    |______|   |      |
> >         =3D 100uF=3D 0.1uF    |      =3D 0.1uF=3D 100uF=3D0.1uF   |    =
  =3D 0.1uF=3D 47uF
> >         | 40V  |          |      |      | 40V  |        |      |      |=
 10V
> > 0V    --+------+----------+------+------+------+--------+------+------+=
----> GND
> >  		 	   		 =20
> > --=20
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