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RevB  RevC Altium Library

Former Member

Looking at the RevC change notice all I can see is that an onboard foot print was changed in order to allow the correct use of a multiplexor. Having said that are the RevC Altium libraries just an attempt to keep the documnetation revision numbers inline or has the footprint and pin definition for the carrier connectors changed as well?

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    The PCN14003 for PicoZed 7010/20 did not affect the footprint or pin definition for the JX microheaders, although it does affect the functionality of a few of those pins.

     

    The multiplexer in question relates to the eMMC and the MIO it uses. To add flexibility to the SOM, a multiplexer was added so that those who did NOT want to use the eMMC but preferred access to the MIO through the JX connectors could do this through the mux. Unfortunately, the implementation on Rev B had an error, so the Rev B boards hard-wired the MIO to the eMMC, and the shared pins on the JX connectors were not connected to anything. On Rev C, the mux was fixed, so through software control, a user can choose whether the MIO are connected to the eMMC or the JX connectors, with the default being eMMC.

     

    The difference in the Rev B vs. Rev C Altium symbols is on JX3.40. On Rev B, this is connected to GND. On Rev C, you have the option to connect this to MIO47 (through resistor jumper JT7). Adding MIO47 to the JX connectors made it possible to potentially support access to the 2nd PS USB controller.

     

    Bryan