Arduino Forum

Development => Other Hardware Development => Topic started by: avsys on May 02, 2013, 11:13 am

Title: How to make a FTDI adapter? for arduino
Post by: avsys on May 02, 2013, 11:13 am
hi,
i need some help on making a my own FTDI adapter, i'm going to use this schematics,
http://www.sparkfun.com/datasheets/DevTools/Arduino/FTDI%20Basic-v13-5V.pdf (http://www.sparkfun.com/datasheets/DevTools/Arduino/FTDI%20Basic-v13-5V.pdf)
i'm confused with pin 4, which is labeled as "Power" to where should i connect it with?
Title: Re: How to make a FTDI adapter? for arduino
Post by: Riva on May 02, 2013, 11:23 am
It should be connected to pin 4 of JP1 connector on right of schematic.
Title: Re: How to make a FTDI adapter? for arduino
Post by: avsys on May 02, 2013, 11:56 am
thank you for the reply,
what is the meaning of "SJ"
you mean connection should be made to the 3.3v supply line?
Title: Re: How to make a FTDI adapter? for arduino
Post by: Riva on May 02, 2013, 12:21 pm

thank you for the reply,
what is the meaning of "SJ"
you mean connection should be made to the 3.3v supply line?

SJ is a solder jumper so you can supply either 3.3v or 5v to pin 4 of the JP1 connector to power the device it's connected to (some Arduino's are 3.3v and others 5v).
Pin 4 of the FT232RL (named POWER) should be connected to pin 4 of JP1 (also called POWER)
If you look at the FT232RL datasheet (http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT232R.pdf) you will see this pin is used to derive the UART voltage levels.
The user bridges the SJ2 solder joint to select 3.3V/5.0V voltage level supplied to the attached device and this voltage is also applied to pin 4 of the FT232RL chip (through a trace/wire called POWER in the schematic) so it knows what voltage to drive the CTR, DTR, TX & RX pins at.
Title: Re: How to make a FTDI adapter? for arduino
Post by: avsys on May 02, 2013, 04:21 pm
Thanks a lot.  :)  :)