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Author Topic: It is "safe" to have a serial port connected to an unpowered TTL shifter?  (Read 599 times)

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Offline mcinqueTopic starter

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It is "safe" to have a serial port connected to an unpowered TTL shifter?
« on: May 01, 2019, 07:40:14 pm »
Hello all, 

let's assume we have a CHIPI-X USB to serial adapter... do you see any potential issue for the serial port if the chip is leaved unpowered but connected to an active RS232 serial port (loops, shadow voltages or currents or any other issue)?

There is a level shifter between the serial and the serial bridge, should it be totally passive if unpowered, do you agree?

« Last Edit: May 06, 2019, 07:34:15 am by mcinque »
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Offline mcinqueTopic starter

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Re: FTDI FT231X chip unpowered, any potential issue for the active serial port?
« Reply #1 on: May 01, 2019, 07:43:39 pm »
Level shifter diagram. It is powered by the VCCIO generated by the FT231X.

Should be totally passive if unpowered, do you agree?
« Last Edit: May 06, 2019, 07:34:51 am by mcinque »
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