Problem: EMIC2 + Arduino-Due + Level-Converter (TXB0108)
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Problem: EMIC2 + Arduino-Due + Level-Converter (TXB0108)

by randomvibe on Sat Jan 19, 2013 5:36 am

I'm having intermittent problems with this setup: EMIC2 + Arduino-Due + Level-Converter (TXB0108). I traced it to the TXB0108. Background:

The EMIC2 works perfectly on its own when I interact with it using my desktop serial port and terminal program (PuTTy).

The Arduino-Due's hardware serial also works fine when I test it with my desktop and PuTTy.

The Adafruit TXB0108 between the Due and emic does not work. If I directly patch Due-TX to the EMIC-SIN pin (SIN is 3.3V compliant per spec), then It does work intermittently, however hangs now and then because the TXB0108 delays or completely fails to pass EMIC's ready-to-receive-command symbol.

All problems disappear when I directly patch Due-RX to EMIC-SOUT, and bypass TXB0108 completely. Now I risk damaging the Due.

The TBXB0108 is known to have issues with I2C. Is it known to have issues with the Arduino Due hardware serial ports? Do I need to add a resistors and/or other components somewhere? Thank you.
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Re: Problem: EMIC2 + Arduino-Due + Level-Converter (TXB0108)

by adafruit on Sat Jan 19, 2013 8:49 am

Never heard of a problem with serial - do you have any pullups or anything?
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Re: Problem: EMIC2 + Arduino-Due + Level-Converter (TXB0108)

by randomvibe on Sun Jan 20, 2013 2:38 am

adafruit wrote:Never heard of a problem with serial ...

Have you tried the TXB0108 through hardware serial? From an A-Due? A-Due's are very new I realize.

adafruit wrote: - do you have any pullups or anything?

No pullups, just A-Due to TXB to EMIC2. Are pullups required for serial? Anything else needed?

Or, is there a better option over the TXB0108 for this application? Thank you.
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Re: Problem: EMIC2 + Arduino-Due + Level-Converter (TXB0108)

by adafruit on Sun Jan 20, 2013 12:33 pm

we have not tried it, but also don't know why it wouldn't work. you could try our FET based 4-channel shifter.
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Re: Problem: EMIC2 + Arduino-Due + Level-Converter (TXB0108)

by randomvibe on Sun Jan 20, 2013 10:35 pm

adafruit wrote:Never heard of a problem with serial - do you have any pullups or anything?


Are you also suggesting I try to adding pullups? What value and on which side (3.3V, or 5V, or both)?
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Re: Problem: EMIC2 + Arduino-Due + Level-Converter (TXB0108)

by adafruit_support_bill on Mon Jan 21, 2013 7:16 am

No, you should not need pullups for serial.
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