Dead USB

trying to give the lime mini another go before it goes in the bin…my suspicion is the FT601Q FTDI chip is dead or something around

it…I have got to the point where VD10_FT which should be 1v…but it is SC to GND, anyone with real low level h/w experience on these can give some pointers ? I am willing to change the chip, i assume it will need flashing or config to work then on the lime (vendor id’s…gpio settings etc) ?? alternatively, I am willing to buy any limemini which has other issues but functioning USB

FT601 doesn’t have firmware to load. Not sure about other config, but @Zack could advise.

Hi @9H1LO,

Could you be more specific on how do you measure, please.

thanks for your replies…device is not detected on the USB bus, after a heatsink coming loose and falling on the USB connector a few months ago

I power on via USB and check all the main voltages from the regulators and they are fine

I am measuring with a volt meter around the FTDI chip and VCCIO and VCC33 are good but VD10 which should be +1v from internal LDO on FT601 is not present, actually the line is short circuit to GND, to verify i checked across C147 which is on AVDD_FT line on this power bus and it shows 0 ohms to ground so I am thinking either some capacitor is SC or the FT601


Hi @9H1LO,

It really looks like FT601 was damaged in this case.

Here is FT601 configuration we use:

thanks @Zack

just an update, I have removed the ft601q from the board with hotair station and the SC on DV10, VD10 and across C147 is now gone so it looks like the chip has internal SC

I will replace the chip and try those parameters, now looking for supplier that doesn’t charge 4x chips price for shipping haha :stuck_out_tongue:

hopefully chip removal hasn’t cause any damages (needed quite some heat and FPGA is VERY close) and hopefully replacement will get it working and this tread may come useless to others in the future, will post updates when chip is replaced

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Good luck @9H1LO. Keep us informed please.