Microcontroller powered from the battery gives reverse voltage through UART to FT232RL chip

[venkateshhkmvt]

Hi,
i have powered my microcontroller from the battery. and have connected the Microcontroller UART connected to FT232RL converter.
Now the problem is, when the MCU is powered, the UART voltages come in to the FT232RL resulting in the damage of FT232RL chip.
can you please advise on how to fix this issue?

Regards,
Venkatesh

 

[KlausST]

HI,

show the complete circuit

Klaus

 

[paulfjujo]

hello,

what is the DC voltage of you battery ?
is your FTDI powered by 3,3V or 5V DC ?

There are 2 kind of USB/UART converter :
5V DC or 3,3V DC

generaly, it is he reverse,
without MCU power supply
the USB/TTL converter can power on , the MCU trough the UART RX pin !
i encouter this problem with Prolific cable ...
but never destroyed it ,due to MCU POWER SUPPLY

 

[FvM]

FT232RL has no problems to handle 3.3 and 5V logic interface as well as external supply voltage, but it has to be connected according to the datasheet specification. Show your schematic.

The situation may be different with ready made converter modules or cables that don't support all available chip options and have e.g. fixed wiring for 3.3 or 5V supply voltage.

 

[Carry for cents bazar]

I agree, the problem is most likely in a connection.