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Topic: IIC I2C interface Level Conversion Module 5-3v

The content of this topic has been archived on 17 Apr 2018. There are no obvious gaps in this topic, but there may still be some posts missing at the end.

Low cost (under $2) Level convertion modules used to interface 3.3v router UART with a 5v FTDI USB to TTL breakout board (or arduino). No 10k pullup resistor needed! I am assuming this method will work with any of the gpio stuff (including i2c) ... but I haven't confirmed this yet.

http://i51.photobucket.com/albums/f382/sfranzyshen/convert.png
http://i51.photobucket.com/albums/f382/sfranzyshen/convert2.png

this one I haven't tested yet! ... probably still need pullups on the router side ...

http://i51.photobucket.com/albums/f382/sfranzyshen/convert3.png

(Last edited by sfranzyshen on 3 Nov 2013, 02:11)

USB-UART adapter based on CP2102 IC is definitely a better option... it costs less than this level shifter and can operate at 3.3 V levels.

pepe2k wrote:

USB-UART adapter based on CP2102 IC is definitely a better option... it costs less than this level shifter and can operate at 3.3 V levels.

that is true if all you are trying to do is connect to usb ... but what if I want to connect directly to an arduino's uart or i2c? without using usb? btw these modules operate at 3.3v and are 1/2 the cost of a cp2102 adapter ... oh ... and no hardwired pullup resistor ...

(Last edited by sfranzyshen on 2 Nov 2013, 17:56)

sfranzyshen wrote:
pepe2k wrote:

USB-UART adapter based on CP2102 IC is definitely a better option... it costs less than this level shifter and can operate at 3.3 V levels.

that is true if all you are trying to do is connect to usb ... but what if I want to connect directly to an arduino's uart or i2c? without using usb? bwt these modules operate at 3.3v and are 1/2 the cost of a cp2102 adapter ...

4x BSS138, 8 resistors and I can make bi-directional level shifter myself. Or buy it on Ali for about 1,5~2 USD, including shipping costs smile

sfranzyshen wrote:
pepe2k wrote:

USB-UART adapter based on CP2102 IC is definitely a better option... it costs less than this level shifter and can operate at 3.3 V levels.

that is true if all you are trying to do is connect to usb ... but what if I want to connect directly to an arduino's uart or i2c?

i will power my arduino with 3.3v.

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