Difference in TXB0104 and other 4 channel logic level conver

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saasmath
 
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Difference in TXB0104 and other 4 channel logic level conver

Post by saasmath »

I am using a Raspberry Pi to control in iRobot Create.

The Cargo Bay connector on the iRobot Create has 5 volt ttl serial in and out, so I purchased a TXB0104 level shifter first from Smartfun and then from Adafruit to convert the 3.3 volt output from the rPi. The TXB0104 seemed to partially connect in both cases, but were very unreliable and got mostly noise when I tried to look at the serial communication (but there was some output).

Finally, I was able to get it to work well with the Adafruit 4 channel, I2C safe logic level converter (part number 757).

While this was a solution, I am curious why the TXB0104 does not work. Do I need to have some type of pull up resistor or capacitor or something else to make it work. The TXB0104 also has an "OE" pin which I am leaving disconnected. Does this need to be grounded or pulled high to get things to work.

Thank you for your help in helping me understand the problem.

--Gary

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adafruit_support_rick
 
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Re: Difference in TXB0104 and other 4 channel logic level co

Post by adafruit_support_rick »

OE is the output enable pin. It must be pulled high for the device to work. If you left it unconnected, that could explain the unreliable operation.

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