Author Topic: Old R4 USB Mote - pre fix for added resistors  (Read 1078 times)

HeneryH

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Old R4 USB Mote - pre fix for added resistors
« on: December 13, 2018, 02:09:13 PM »
I have an old USB-Mote that was the R4 design exhibiting all of those problems with USB connections due to the missing resistors and one other change.

My computer just won't recognize the FTDI adapter on-board.

I had these same problems a while ago and never got around to cutting traces and hacking in the surface mount resistors.  My eyes, dexterity, tools and general motivation  just weren't up to the task so I set this older USB-Mote aside unused.

Now that I am out of Motes, I need to try to resurrect this device.

I'm trying to bypass the built-in FTDI chip and use an external FTDI adapter right to the Tx/Rx pins.

Not working :(

I'm guessing that the presence of the on-board chip is interfering with me tapping into the Tx/Rx lines.

Any suggestions other than trying to find those tiny surface mount resistors, cutting traces and trying to solder them inline?

This is what I am trying:



Here is the old posts about the bug with the R4 design:  https://lowpowerlab.com/forum/moteino/ftdi-ft231-ft232-drivers/msg5600/#msg5600

Felix

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Re: Old R4 USB Mote - pre fix for added resistors
« Reply #1 on: December 13, 2018, 02:58:50 PM »
Try a few other cables, shorter is better, you might be in luck.

Grimley

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Re: Old R4 USB Mote - pre fix for added resistors
« Reply #2 on: December 14, 2018, 07:15:59 AM »
Why is shorter better btw, Felix? I'm just curious.
I was blown away by these weight loss shakes and how effective they are.

Felix

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Re: Old R4 USB Mote - pre fix for added resistors
« Reply #3 on: December 14, 2018, 08:12:07 AM »
Generally shorter is always better :)
Less noise pickup, less voltage drop etc.
A great cable would also be shielded to minimize noise.