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Topic: [solved] USB to Serial TTL Question (Read 1 time) previous topic - next topic

pcfr33k

#5
Oct 06, 2012, 03:42 am Last Edit: Oct 06, 2012, 03:49 am by pcfr33k Reason: 1
Thanks again for the replies.  I had a link to the product I bought in my first post.  I measured each line. Vcc +5 measures +5.  Vcc 3.3 measures 3.288   Rx and Tx measure just under 5 volts each.  I used the ground as reference when measuring each pin.

Something sounds wrong with this device.

I have another USB to serial that has a jumper one for +5 and other for +3.3 so they measure correctly.  When +5 is enabled I measure Rx/Tx juts under 5 volts and when I enable +3.3 I measure just under 3.3 volts for the Rx/Tx using ground for reference.

CrossRoads

What sounds wrong? Levels sound good. Hook up +5, Gnd, connect Tx to Arduino Rx and Rx to Arduino Tx.
Press reset on your board when the IDE says "Compiled xxx of 32xxx bytes".
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

pcfr33k

So if I use the unit that has +3.3 and +5 Vcc out and use the +5 Vcc out and the Rx/Tx that measure under +5volts I should be ok?

What the heck is the purpose of having +3.3 Vcc if Rx/Tx does not change to 3.3 and remains under 5?

I am trying to figure out why this USB to Serial was made this way and how it could be used practically!!!

CrossRoads

"So if I use the unit that has +3.3 and +5 Vcc out and use the +5 Vcc out and the Rx/Tx that measure under +5volts I should be ok?"
Yes.

"What the heck is the purpose of having +3.3 Vcc if Rx/Tx does not change to 3.3 and remains under 5?"
Some devices need 3.3 for Vcc but have 5V tolerant IO pins.

"I am trying to figure out why this USB to Serial was made this way and how it could be used practically!!!"
Ignore the 3.3V.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

pcfr33k

#9
Oct 06, 2012, 04:06 am Last Edit: Oct 06, 2012, 04:07 am by pcfr33k Reason: 1
Thanks!!

How do I modify the original subject to show [solved]

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