Some MB393 boards have USB defective!

nopti_albe · ‎2005-09-06

Posted on September 06, 2005 at 15:12

nopti_albe · ‎2005-09-06

Posted on September 06, 2005 at 11:07

I had a lot of problems with the USB on my MB393B v2.04! If you can't seem to make your USB work look at the D+ and D- signals (with a scope on resistors R13 and R14) and if they are both positive just replace the crap of circuit and put your own... it will work from first try.

anis_ben_abdallah · ‎2005-09-06

Posted on September 06, 2005 at 11:44

Hi Tudor,

Yes , you are right it is possible to eliminate the USBUF01W6 IC which is only a USB filter IC , it was unfortunately uncorrectly mounted on the board.

But we have done some tests, even mounted in the wrong way , the usb is still working fine.

But as you mentionned , you could replace this chip by the pullup.

Ciao

Programmer

nopti_albe · ‎2005-09-06

Posted on September 06, 2005 at 15:12

On MB393-2.04 it looks to be mounted correctly, i've checked with it's datasheet. On my board it pulls up both D+ and D- so USB doesn't work fine anymore. What seems to me wrong is that the board was shipped to me not functioning... but anyway... it works now and I'm happy ;)

PS on another str710 board from hitex it's true that the links are done the other way round. Could that be the problem? There are just a couple of diodes in it... what could go so wrong with such a simple circuit?

[ This message was edited by: tudor on 07-09-2005 10:27 ]