Hi All,

Does anyone know the source of the signal "GCLK" on the Cmod A7? The source for "GCLK" appears to be "usb_12MHz" ... however, there is no reference to this signal on the schematic (as far as I can tell). At first, I thought "GCLK" was driven by the 100MHz oscillator, then I noticed that this component was a "no-load", sure enough, I can measure a 12MHz signal directly on the board and the timing of my strobes validates that.

Does anyone have any insight?

Many thanks,

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Hi @Tim H,

If you look at the bottom of page 3 of the schematic here. You can see the 12 MHz clock. The 12 MHz clock is part of the programming circuit that is not made public. The programming circuit is page 5 which intentionally left blank.

thank you,


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