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Topic: True 3.3V ftdi to ttl adapter? (Read 1 time) previous topic - next topic

mikelemon

Hello there,

I'm looking for a simple pcb solution of an ftdi to ttl adapter that operated at 3.3V logic level.

Couldn't find one so I'm looking at the CP2104 ic solution and create my own solution that will also utilize one of the more modern usb type C or micro usb connector the question is what additional parts will it require to do the task sins the IC is affected by the 3.3V VBUS rail from the USB.

Thanks for helping.

ieee488

I have an adapter - purchased on eBay - based on Silicon Lab's CP2102 which according to the datasheet is 3.3V logic level. I use it to communicate with ESP-01.

I don't know if this is what you are looking for.


uxomm

#2
Apr 29, 2018, 03:16 am Last Edit: Apr 29, 2018, 03:17 am by uxomm
I use this FTDI USB to TTL Adapter: FT232RL
It has a switch to select 5 Volts or 3.3 Volts as the logic level.
This adapter I use mainly to program ESP8266 (switch set to 3.3). It works pretty well.
Always decouple electronic circuitry.

mikelemon

I use this FTDI USB to TTL Adapter: FT232RL
It has a switch to select 5 Volts or 3.3 Volts as the logic level.
This adapter I use mainly to program ESP8266 (switch set to 3.3). It works pretty well.
The question is if that communication line it's self is running at 3.3V and not VBUS (5V)?

Because I don't see any level shifting in the schematic.

uxomm

The FTDI chip does it internally.
From the datasheet:
Quote
VCCIO
+1.8V to +5.25V supply to the UART Interface and CBUS group pins (1...3, 5, 6, 9...14, 22, 23). In USB bus powered designs connect this pin to 3V3OUT pin to drive out at +3.3V levels, or connect to VCC to drive out at 5V CMOS level. This pin can also be supplied with an external +1.8V to +2.8V supply in order to drive outputs at lower levels.
Pin 1 is TX
Pin 5 is RX
Always decouple electronic circuitry.

avr_fred

The FT232 can operate with its I/O down to 1.8 volts. The Sparkfun board provides VCCIO voltage switching for both 3v3 and 5v I/O operation. Refer to page 10:

http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT232R.pdf

FWIW, Chinese FT232 breakout boards with the .100 pin header jumper for 3.3/5 switch VCCIO correctly. If the board has a solder pad only for voltage switching, it's not correctly implemented. YMMV.




mikelemon


bishaldutta

I use this type of FTDI chip for my both 3.3V and 5V requirement.

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