Hi all! Can some one (hopelly prom Xilinx) tell me why when I connect a monitor to ML403 Borad, the board doesn't boot (error LED ON) if the monitor in ON BEFORE the board. But if I turn ON the board BEFORE the monitor all is ok. Very strange !! Is there some way to fix it ?
A+ Mehdi
Try to power cycle the board several times. If that helps you are more likely to see a problem described in Answer Record #22179
- Peter
GaLaKtIkUs? wrote:
If pushing the system ace reset button on the board clears the error and allows the board to boot, then the problem is the probably the power up reset circuit inside the system ace chip. It has been our experience that the power on reset in the system ace is not 100% reliable, and a power on reset IC is a really good idea. We never did characterize what it was about our design that caused this problem, could have been power supply sequencing or ramp rates.
The external monitor might be leaking enough current into one or more signal pins to raise the power rail on the board to something slightly higher than zero, thus changing the power up characteristics. Alternately, the additional load could be changing the rate at which one or more of the power supplies is coming up.
We have used the TC542702 voltage detector from Microchip on a number of different designs with the system ace. This will keep the ace in reset until the 3.3v rail hits 2.7V.
Regards, Erik.
I already tried the reset button and it didn't solve the problem. The only solution was to turn off both of the card and the monitor, than turn on the card BEFORE the monitor.
Mehdi
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