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akoutmos / nerves_weather_station

This repo contains the companion code for the PragProg Nerves book.
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tcn75a nerves rpi2 #1

Open alpa669 opened 1 year ago

alpa669 commented 1 year ago

Hi, i have a system with raspberry 2, nerves and tcn75a but Circuits.I2C.detect_devices() command not return nothing device on i2c bus. The sensor tcn75a is supported?

Thanks

fhunleth commented 1 year ago

Hi @alpa669,

I haven't used the TCN75A, but I'd expect it to work fine with Nerves. The Circuits.I2C.detect_devices/0 function can't detect all devices so this might be one that doesn't work with it. I looked at the datasheet and didn't see any of the hints that it might not detect, though. Could you double check the wiring and try again? If it still doesn't detect, I'd try reading and writing to it. If it's like the other stealth devices that Circuits.I2C.detect_devices/0 doesn't detect, it will work.

alpa669 commented 1 year ago

Hi fhunleth, thanks for reply. I checked the wiring and the sensor is powered and connected at SCL and SDA of rpi2. tcn75a If it's a stealth device how to do discover proper address? Thanks

fhunleth commented 1 year ago

It would be in the documentation for the board that you have. I'd assume you'd get that from www.microbot.it.

Looking at the TCN75A datasheet, my guess is that it's 0b1001000 (binary), so 0x48 in hex. That's on page 11. The address is settable, though, so www.microbot.it should have the best answer. If it's not 0x48, it will be one of the addresses between 0x49 and 0x4f inclusive.

alpa669 commented 1 year ago

I'll try the [0x48..0x4f] address as you suggest. Thanks