Hello everyone,
I recently implemented the SHT35-DIS-B2.5kS sensor in my system with the teensy. I followed the circuit
schematic shown in the picture, but I am receiving the byte '4' when I try to establish communication with the component.
I would be grateful to know the reason for this issue.
Thanks.
Which Teensy?
Pin 18 of U1 (I assume that that is the SDA pin on the Teensy) is directly connected to 5.5V. Most Teensies are 3.3V boards so I doubt that it will like 5.5V on that pin. Even for a 5V processor 5.5V is at the edge (read: not advisable).
Hi @ferhatag. Welcome to the forum!
Indeed, I assume that should be a pull-up and the diagram has been drawn incorrectly? Otherwise if its been wired like that, then, in addition to the risk of damage to the Teensy, the SDA line would be permanently in a high state.
According to its datasheet, the sensor can be supplied with anything between 2.15V and 5.5V. We can't see how the rest of your Teensy is wired because you have shown only a part of your diagram, but might it be simpler to supply both sensor and Teensy with 3.3V? It would eliminate the need for level shifting between the 5V signal from the sensor and the 3.3V Teensy.
If you have not tried it yet, the address of an I2C device can be determined by using the example I2C scanner sketch - see File->Examples->Wire->I2C Scanner or File->Examples->Wire->Wirescan.
BTW, I have corrected the typo in the title of your post.
Hello @BitSeeker,
Thank you for the suggestion. For the moment, I’m powering the Teensy via USB to test this part of the system, so it doesn’t require an external supply. The rest of the system is independent, and I only borrowed its supply line.
I’m considering using the 3.3 V provided by the Teensy to power the sensor and to connect the pull-up resistors for the I²C lines.
Thanks.
Pin18 of the teensy is connected to the wrong side of the pull up resistor.
If you actually have connected it that way, then say goodbye to the teensy.
5volt on pin18 would have fried the pin, or the whole chip.
Leo..
