Lpc2000

----- Original Message ----- 
From: "David Willmore" <willmore@...>
To: <lpc2100@yahoogroups.com>
Sent: Wednesday, January 07, 2004 10:15 PM
Subject: Re: [lpc2100] MAX3232 problems?


> > Do the CAPS have the right polarity ?
> > Pay attention: Pin 6 is the - side of the CAP, GND this time the '+'
side.
> > Same thing for Pin 2: - side to VCC 3.3 and + side to Pin 2.
>
> Used ceramic caps.  Thought they were too small, so I replaced them with
> 4.7uF tants--which I was very sure to follow the data sheet and get the
> polarity right.  So, that's probably not it.
>
> The datasheet shows the V+ cap going to ground on the - side, but Leon's
> board has it going to Vcc.  That shouldn't make a difference, but it's
> a little difference that I noticed.

Oops! You are right. It could cause a problem with a polarised cap. Try
putting it the other way round.

I'll correct the schematic and fix the problem if I get some more boards
made. I'll modify
any more boards I send out.

100 nF ceramic caps are really all that is needed. The older MAX232 needs 1
uF.

Leon
--
Leon Heller, G1HSM
Email: aqzf13@...
My low-cost Philips LPC210x ARM development system:
http://www.geocities.com/leon_heller/lpc2104.html