Minimum required HW for G120TH


It seems that a minimum HW needed to get G120TH running is 3.3 V power supply AND 5V power supply.

5V is needed to USB client connector. That will be used for debug and application deployment.

Is this correct? According schematic G120TH includes RTC crystal, USB client connector capacitors etc

  • jari

In addition what wonders me whether those loader pins LDR0 and LDR1 are needed on G120TH.

I have FEZ Cobra III and those pins are available by buttons but I haven’t never used them.

And hard to figure out why I would need them … ??

  • Jari

check the developers guide (linked on the resources of the product page - direct link). You only need 3v3 for operation. 5v power on USB connection will come from PC, but is not used to power the board (see developers guide) and therefore a 5v supply will not be necessary to debug your app.

You need LDR’s for booting into bootloader mode so you can update firmware. Check the G120 SOM datasheet for details. If you have the full GHI loader installed you may not have ever booted into bootloader mode yourself but let Fez Config do it for you, but you should still know where the pads are in case you ever needed to do that manually to erase a rampant application or recover from some other situation.

@ jari - you do not need 5v, only 3.3v.

See this video please

ok. Thank you !!

If you want to power it via USB, you can solder an LM1117 (or something with the same pinout) onto the power-pins of the TH-Module (I think I already posted that solution on the forums some time ago :think:, see the picture below)… If you like it more efficient you can use a switch-regulator (also available as module e.g. this has a compatible pinout LM3671 3.3V Buck Converter Breakout - 3.3V Output 600mA Max : ID 2745 : $4.95 : Adafruit Industries, Unique & fun DIY electronics and kits). I like these solution, especially when using breadboards.


@ glx - very cool. Tweeted and FB it.

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