Re: [uCsimm] spontaneous reboots

From: Florian G. Pflug (
Date: Fri Dec 01 2000 - 19:37:07 EST

On Thu, Nov 30, 2000 at 02:46:12PM +0100, daniel haensse wrote:
> Hello,
> pin 8 on the uCSimm is an input to the maxim MAX 6319 reset device, but there
> is no external pull-up resistor (internal resistor is 52kOhm).
> I have put a resistor on the uCgardener board (2k pin 8 and pin7) and
> would suggest to put the pin 8 on vdd if manual reset is not needed. I think
> this is not the final solution to the problem, since their is a correlation to
> network traffic. I guess it is a problem with the 3.3V traces on the uCSimm. Did
> somebody try to connect a capacitor on the vdd and gnd pins of the max6319,
> directly next to the chip (this is a little bit a symptomatical solution) ?

I has been a time since a last worked with my ucSimm, but I remember the the
ethernet-controller drew quite a lot of current. If I connection power-suppy to an oscilloscope
as well as to the ucSimm, I had noise of some hundred millivolts on the
power-supply (_before_ the linear regulator, of course) as soon as I started
pinging the ucSimm.

So I guess, the if you have power-suppy problems, than network traffic will
amplify you troubles.

mfg, Florian Pflug
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