Hi,
Can i connect a 5v FTDI adapter to my Moteino? The FTDI will change to 3,3v ? Or the FTDI must be 3,3v ?
Depends on the FTDI adapter. Some are 3.3v/5v compliant others, not so much. The one I have came from ADAFruit, and I'm glad to say that it is 3.3/5v capable, since I have been using it without checking it until you posted. http://www.adafruit.com/products/70 (http://www.adafruit.com/products/70) (5v supply line, 3.3v signals, Felix took care of the supply with Moteino's on board regulator.)
They also have an "FTDI Friend" which allows you to manual set 3.3v or 5v for systems that require it one way or the other, and swapping RTS with DTR: http://www.adafruit.com/products/284 (http://www.adafruit.com/products/284)
Since you thought of it beforehand, check on it with the manufacturer, no sense in letting out the magic smoke if you can avoid it!
LG
Quote from: LazyGlen on January 09, 2014, 11:11:36 PM
Depends on the FTDI adapter. Some are 3.3v/5v compliant others, not so much. The one I have came from ADAFruit, and I'm glad to say that it is 3.3/5v capable, since I have been using it without checking it until you posted. http://www.adafruit.com/products/70 (http://www.adafruit.com/products/70) (5v supply line, 3.3v signals, Felix took care of the supply with Moteino's on board regulator.)
They also have an "FTDI Friend" which allows you to manual set 3.3v or 5v for systems that require it one way or the other, and swapping RTS with DTR: http://www.adafruit.com/products/284 (http://www.adafruit.com/products/284)
Since you thought of it beforehand, check on it with the manufacturer, no sense in letting out the magic smoke if you can avoid it!
LG
Thanks LazyGlen for the explanation =)) I have see a lot of FTDI's... They support 5V input but i must see 3,3v output to connect to Moteino, right? And some FTDI can be regulated to 3,3v or 5v output (you can chose) to connect Moteino (3,3v).
It's a new world out there... at lest for me and i love it =)))
LET's GOOOO...
Love the magic smoke ;D
Quote from: arrinkiiii on January 10, 2014, 05:07:02 AM
Thanks LazyGlen for the explanation =)) I have see a lot of FTDI's... They support 5V input but i must see 3,3v output to connect to Moteino, right? And some FTDI can be regulated to 3,3v or 5v output (you can chose) to connect Moteino (3,3v).
It's a new world out there... at lest for me and i love it =)))
LET's GOOOO...
Love the magic smoke ;D
Correct. A 3.3v/5v FTDI will tolerate 5v into it's inputs, recognizes 3.3v into a input as a high logic level and drives 3.3v out of the outputs. From the Sparkfun web site the pinout is: RTS, RX, TX, VCC, CTS, GND (RTS is the green cable and GND is black). Some FTDI cables put 5v on Vcc, some 3.3v. What version FTDI you need is dependent on what it is plugging into. Apparently Felix's design runs the VCC provided from the FTDI through the regulator, therefore it is safe to put 5v on this pin for Moteino's, and we know that Moteino's run at 3.3v, so the data pins must not exceed 3.3v. Other (larger) systems may not power up the whole board from FTDI, just the processor for programming, so 5v on VCC in that system would not be good if the processor was 3.3v. If that processor was 5v, it
might not recognize 3.3v on an input as a logic high, and therefore would not program.
Some FTDI ports use RTS (Request To Send), others instead use a signal called DTR (Data Terminal Ready). These signals allow for the control of the flow of data between the host and the target, and behave slightly differently. Moteino uses RTS, it sez so right on the silkscreen. AdaFruits FTDI Friend https://www.adafruit.com/products/284 (https://www.adafruit.com/products/284) allows you to change all 3 of these settings; VCC, V
input/output -or- signal and RTS/DTR. Options are good, but if you forget that you changed it from one to another and plug it in without checking...
Most people who work or play with electronics have proven to themselves that electronics run on Magic Smoke, because once you let it out of the little chip, the chip does not work anymore! Some are satisfied by proving it once, others need to prove it over and over again.
LG
WOW :o Thank you LG for explaining so good and simple. Most FTDI that i can find in Portugal don't have RTS but they have DTS. I will order one from LowPowerLab, will take time to arrive but... cê la vie :) :)
Quote from: LazyGlen on January 10, 2014, 07:40:25 AM
... A 3.3v/5v FTDI will tolerate 5v into it's inputs, recognizes 3.3v into a input as a high logic level and drives 3.3v out of the outputs. From the Sparkfun web site the pinout is: RTS, RX, TX, VCC, CTS, GND (RTS is the green cable and GND is black). Some FTDI cables put 5v on Vcc, some 3.3v. What version FTDI you need is dependent on what it is plugging into. Apparently Felix's design runs the VCC provided from the FTDI through the regulator, therefore it is safe to put 5v on this pin for Moteino's, and we know that Moteino's run at 3.3v, so the data pins must not exceed 3.3v. Other (larger) systems may not power up the whole board from FTDI, just the processor for programming, so 5v on VCC in that system would not be good if the processor was 3.3v. If that processor was 5v, it might not recognize 3.3v on an input as a logic high, and therefore would not program.
So, it sounds like you can't use a 5 volt FTDI board with the Moteino. The 5 volt Vcc is not a problem, but the 5 volt data lines are a problem. Is that correct?