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Topic: FTDI vs Logic Level Convertor used with wifi esp8266 module (Read 579 times) previous topic - next topic

shariq_azim

Hi all,

I am really confused which one to buy FTDI or logic Level Convertor to transmit data and connect to another esp8266 module. 

What are the difference?

Why is voltage divider not prefered?

DrAzzy

Your question as written is nonsensical - you don't seem to know what you're buying or what they're for.

FTDI is a company. They make electronic components. For a long time, they made the only commonly used USB-Serial adapter IC. The term "FTDI adapter" became synonymous with a USB serial adapter with the 6x1 pin header with Gnd-CTS-Vcc-Tx-Rx-DTR pinout for plugging directly into an Arduino Pro Mini (note - I may have TX and Rx swapped there, I always have to look that up). Nowadays, it is not unusual for USB-serial adapters with non-FTDI USB-serial adapter IC's to be casually referred to as "FTDI adapters". I recommend referring to all USB-serial adapters as "USB serial adapters". There's some bad blood between hobby community and FTDI over their response to a wave of counterfeit chips last year (google ftdigate for more info), too - basically, any USB serial adapter with an FTDI FT232 chip manufactured in 2015 or 2016 has a high chance of having a fake chip that won't work with current drivers.

A USB serial adapter can be used to connect an ESP8266 to a computer for programming or otherwise communicating with the ESP8266 over serial. It cannot be used to interface the esp8266 with another microcontroller. I recommend these USB-serial adapters - http://www.ebay.com/itm/232229675924 (no endorsement of the specific seller - there are multiple ebay sellers with identical boards at similar price - but the black ones with the switch on them are good, and work set for both 5v or 3.3v, and have the right pinout for programming Pro Mini's if you want to do that in the future)

A logic level converter is used to allow devices with different voltage levels to communicate (for example, to allow a 5v arduino to communicate with a 3.3v esp8266). I recommend the ones with one MOSFET (in SOT-23 package) and 2 resistors per channel for Serial and I2C applications.
ATtiny core for 841+1634+828 and x313/x4/x5/x61/x7/x8 series Board Manager:
http://drazzy.com/package_drazzy.com_index.json
ATtiny breakouts (some assembled), mosfets and awesome prototyping board in my store http://tindie.com/stores/DrAzzy

xl97

^ what DrAzzy said... lol..

but also....

regarding the logic/level shifting for communication with an ESP8266 module..

* many report they DO NOT need to do so (which is only required on the RX line).. (its a gamble that may or may not work)
* many who DO use a logic/level shifter, have successfully used a simple R/R (resistor) based voltage divider.

An "FTDI" (USB to Serial programmer) will be needed in either case...  (unless you plan on using an Arduino in place of one)

I have doen both the above approaches with success..

* I currently have an ESP I cant flash/get into boot mode to save my life though.. regardless fo what pins or grounded or set high...etc.

:(



PieterP


runaway_pancake

"Who is like unto the beast? who is able to make war with him?"
When all else fails, check your wiring!

shariq_azim

hi all,
Apologies for the small confusion.
please‚Äč let me clarify, i want to connect an Arduino uno to esp8266  and similarly connect another uno with a different esp8266.
i am confused with the necessary hardware as in some forums it has been strictly advised not to connect tx and rx pins directly to the module. Now some mention to use a ftdi 232, while some  recommend to use logic level convertor (i believe level shifter are alternative names for the same). There are few sites which prescribes to use voltage divider circuit instead. Now, here lies my confusion

p.s. the unos would be connected to external power supply an not usb(to pc).

thanks again

MarkDerbyshire

Use a Logic level convertor.

An FTDI chip is used in a USB interface which you do not need in your setup.

The problem with a voltage divider is as the current changes when the ESP8266 transmits so will the voltage

shariq_azim

thanks for your response,
An FTDI chip is used in a USB interface which you do not need in your setup.
but for testing with pc i have to use ftdi only? Logic level converter  wont help?

DrAzzy

thanks for your response,but for testing with pc i have to use ftdi only? Logic level converter  wont help?
Exactly.

An "FTDI adapter" (well, any USB-serial adapter) is for interfacing a USB Host (like a computer) to a serial device (like an ESP8266). Be sure to use one set for 3.3v if working with an ESP8266.

A level shifter is for interfacing between two serial devices (or interfacing via I2C/SPI/etc) which operate at different voltages (such as a 5v Arduino Uno and a 3.3v ESP8266).
ATtiny core for 841+1634+828 and x313/x4/x5/x61/x7/x8 series Board Manager:
http://drazzy.com/package_drazzy.com_index.json
ATtiny breakouts (some assembled), mosfets and awesome prototyping board in my store http://tindie.com/stores/DrAzzy

shariq_azim

An "FTDI adapter" (well, any USB-serial adapter) is for interfacing a USB Host (like a computer) to a serial device (like an ESP8266). Be sure to use one set for 3.3v if working with an ESP8266.

A level shifter is for interfacing between two serial devices (or interfacing via I2C/SPI/etc) which operate at different voltages (such as a 5v Arduino Uno and a 3.3v ESP8266).
you just confused me further... LOL . sorry..

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