Analog ADT7420FBZ Question

Apologies, yes. I was following a different diagram.

have u received parts for Sudden Impact Design Challenge ?

Ravi, I have receieved the parts from Farnell I have ordered with the budget (not the outsourced parts, however).

I am still awaiting the challenge kit, eg: Oscilloscope, Analog Kits, etc.

Still having this issue - not sure what is wrong

Hi Joshua,

Could you confirm how the module is wired to the RPI, i.e. Data line to physical pin 3 on the RPI, and Clock line to physical pin 5, VCC to physical pin 1 and Ground to physical pin 6?

Exactly as you said above - all wires to the marked points.

I see, in that case it may be a software issue. From memory, the RPI needs I2C enabled I think, i.e. using the raspi-config program, and then via the 'Advanced' menu option.

I'm presuming you're plugging in just the small board, and not the full eval board? What I2C address are you writing to?

I presume you're following the PDF datasheet pages 13-20 and particularly page 19, which has the read operation?

If you are, then I think scope traces are needed to confirm that the RPI is sending out the correct signals : (

You could also confirm with any other I2C device, to check that your code can successfully talk to I2C devices.

When you get to the register reading stage, from the datasheet page 19 it is clear that you need 'repeated start' capability - and I don't know which RPI libraries support this function

(e.g. if you are using Python for example) - I've never done this on the RPI but I'm sure it has been done by others. Even without repeated start is is possible to successfully write to the device for now (of course the read capability is essential).

I noticed a reference to the ADT7420 in this thread, so it may be worth posting a query on that forum in case anyone has example code to share, to save you time (saves reinventing

the wheel). But I would definitely google for how to do I2C repeated start for the language you plan to use - for example, for C there is the linux/i2c-dev.h functions you could use, as long as the

underlying hardware (i.e. the RPI BCM chip) supports it - I'm fairly sure it does, just I don't have enough experience with the RPI to know for sure, so I hope others can confirm.

Well, I do have a scope on hand so I should be able to check the signals.

In the end the RasPi won't be handling the sensor, but rather the Electric Imp. As I have yet to receive this part, I won't be able to try that.

I was just trying to use the pi to see if I could get it to run, but it seems to be more pain than necessary.

Thanks shabaz, yet again!