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Topic: Logic Level converter help (Read 1 time) previous topic - next topic


That driver module has optos between the inputs and the matching signal positives.

You must connect 5volt of the Arduino/converter to all the signal positives in use.

You can leave ground of the driver connected, but ground has no function here.

I read it has optos on the inputs but I'm trying to learn why the voltage drops when I connect the converter to the driver. The voltage on the B side of the Logic converter is at 5V until I connect the Driver and then it gets cut in half and doesn't send an input to the Driver that it can read(below minimum threshold). Is that a causal effect from the optos?

The 5V from the arduino goes to the logic converter 5V pin which distributes the 5V to the 5V side of the converter(3.3V pin is Va and 5V is Vb on converter).I have supplied both 3.3V and 5V to the converter.

The txs0108 is on a small board like this,(as usual no spec sheet on the board, just the chip)I used the adafruit site which had a similar board but slightly different chip for the wiring.


Jan 13, 2018, 02:58 am Last Edit: Jan 13, 2018, 02:59 am by Wawa
Maybe time we see a real picture of the setup.


I spoke with a guy at EZSBC who looked at the TXS chip and said it wouldn't drive the stepper driver because it didn't have a driver to pull the signal high or low, so I purchased a level shifter from his company and it works great. Here is a link to the converter I bought.

LS2 logic level converter

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