Hi,

Is the DSub male or female? Is it going to be connected to a PC or look l=
ika a=20
PC (DTE or DCE)?

If it is going to be directly connected to a PC it should be a female and=
 pin 2=20
should be TX (output to RX in PC) and pin 3 should be RX (input from TX i=
n PC).

Pin 1 is an input in a DTE (PC) so it looks like you are going to use it =
as a=20
(DCE).

Also put a decoupling cap on the MAX232 (VCC to GND). They can be quite n=
oisy.

Besides what others have said, make a big fat groundplane on the componen=
t side=20
and route as much as possible of signals and power on the solder side. Wh=
en you=20
have to make a jumper on the component (groundplane-) side, make it as sh=
ort as=20
possible (to interrupt the groundplane as little as possible). This appli=
es for=20
two side board with through hole components. If surface mounted component=
s are=20
used, they should be placed at the same side as the traces (opposite to t=
he=20
groundplane).=20

If it is an automotive application, place the board in a metal case, conn=
ect=20
the case to the groundplane (good connection) and make sure the whole box=
 is=20
grounded to the chassis. Preferably bolted directly to it, if not use a s=
hort=20
braid (from a screened cable perhaps).

Regards/Ruben


> Hi guys, this is my first pic project and I'm hoping that some of you
> would be kind enough to review my schematics for mistakes and blunders
> and offer suggestions as you see fit. I don't have a background in EE
> so this is designed with knowledge obtained from the list, internet
> and some old electronics books.
>=20
> http://www.geocities.com/mr_goat2000/schem.gif
>=20
> The intent of this device is to control an electronic transmission.
> There are inputs from a pressure sensor, thermistor and 6 switches as
> well as the LM1815 chip which is meant for a variable reluctance
> sensor. Outputs are to solenoids and the LM7221 which controls a 4
> digit led display.
>=20
> I have USART for debugging and possibly a bootloader in the distant fut=
ure.
>=20
> Do I have adequate decoupling for the automotive environment? Any
> other comments, suggestions are welcome.
>=20
> Cheers,
> Milosz K.
>=20

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
Ruben J=F6nsson
AB Liros Electronic
Box 9124, 200 39 Malm=F6, Sweden
TEL INT +46 40142078
FAX INT +46 40947388
ruben@pp.sbbs.se
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D

--=20
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