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[Gumstix-users] Revised Robostix Proposal
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From: Gordon K. <go...@gu...> - 2005-02-25 15:54:20
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> <title></title> </head> <body bgcolor="#ffffff" text="#000000"> Hi,<br> <br> I have tried to take all points into consideration and I would like to hold a new design out for further comment. Here: <a class="moz-txt-link-freetext" href="http://www.gumstix.org/tikiwiki/tiki-editpage.php?page=+Robostix">http://www.gumstix.org/tikiwiki/tiki-editpage.php?page=+Robostix</a><br> <ol> <li>I revised the board to use 2mm spacing on all connectors except the servos, uarts, and I2C. Servos seem to universally use the 0.100" spacing.</li> <li>Can I do 0.100" board that's bigger? Yes-- but is 2.00mm pitch OK (versus 2.54mm == 0.100")?</li> <li>I have also borought out power and ground adjacent to all signals: AGND and AVCC to the ADC pins, VCC5 to the UARTs, V_MOTOR and GND to the servos, and V_BATT to the remaining power pins. I would especially appreciate comment on this as it pertains to the overall power strategy; namely, that V_BATT is provided as a power source bus, reasonably regulated at 5V and providing 1A total. Vcc is 3.3 and is intended for this board only; Vcc5 similarly.</li> <li>The UART arrangement is a little different, but allows power and ground as well as the chance to jumper level-shifted PXA signals to the ATmega128.</li> <li>The SPI bus is strictly between the PXA and ATmega128 for communication and boot-download at this point, with the PXA as the master and thus limited to 3.6864MHz per the intel docs.<br> </li> </ol> Have I missed anything major?<br> <br> Finally, you may note that there are still a few lines open. Any selections? Oh, and I think that I will bring out the PA onto unpopulated pads on the reverse side.<br> <br> Thanks for the comments,<br> <br> Gordon<br> </body> </html> |