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Post by lbendlin on Aug 29, 2020 6:35:35 GMT -8
My last SunControl board has met its maker (after serving about a year in harsh outside conditions). I had to replace the dead SunControl boards with the older SunAirPlus boards but that came with the inconvenience of gradually losing the INA3221 tracking features. (The SunAirPlus boards are also hogging I2C 0x48 which conflicted with my PaPiRuS display's TM75 temperature sensor)
I was happy to see the SunAirPlus2 boards with Grove connector and a much more agreeable price than the SunControl boards. Ready to swap them in but curious about the I2C address wiring. I need to move at least one of my two boards off 0x40.
The store documentation link for the SunAirPlus2 points to the specification for the older SunAirPlus. I am looking for the actual instructions for the SunAirPlus2, specifically for the I2C address change. Or can I assume that it works just like on the SunControl?
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Post by lbendlin on Aug 29, 2020 8:25:03 GMT -8
Looks like the SunAirPlus2 defaults to 0x41 for the INA3221 - that's a good start. But I don't see any exposed address pins. Do I have to whip out the fine solder kit to attach to pin 5 of the chip?
Is there a difference if I connect to the grove I2C or the "internal" I2C pins? Or are they all on the same address?
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Post by SDL on Aug 29, 2020 9:49:48 GMT -8
lbendlin,
The doc link is a mistake.Fixed now on the product page.. Address is 0x41 on SunAirPlus 2.
External and Internal I2C lines are identical. One is Grove Connector, one is pin header.
No way to change the address without your sensitive soldering. That's a good thing to add on the next revision!
BP
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Post by lbendlin on Aug 29, 2020 10:20:17 GMT -8
I think there's an important difference. On the internal I2C the VCC pin is actually providing power to the I2C bus whereas on the Grove header it is not. I use that to my advantage as I am powering my entire I2C bus from my secondary battery.
I think I soldered it correctly on pin 5, but when I connected that to GND the big blue smoke monster appeared and took the diode SS54 with it (and likely the INA3221 too). Should I have used a 10K or something? Or should I have lifted pin 5 before soldering?
The silver lining here is that I remembered that my trusty old SunAirPlus board is hardwired to 0x40. So now I use a combination of my one remaining SunAirPlus 2 and the old SunAirPlus and I can again access both INA3221 as needed (the new one on 0x41 and the old one on 0x40). I lost the LM75B again due to the conflict on 0x48 but I can live with that. (Edit: I cut pin 8 on the ADS1015 - that did the trick. Was never planning to use the A/D converter anyhow)
Thank you for fixing the doc link. Please note that the document still refers to 0x40 throughout.
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Post by SDL on Aug 30, 2020 14:56:33 GMT -8
Ilbendin, ACK! I have attached a picture of my Box Of Death so I have great empathy for you. Comments: 1) Death and Destruction of the INA3221 - Pin 5 is A0 which is connected to VDD on the INA3221, hence the Blue Smoke and the death of the board, Yes, you should have cut the trace or lifted the pad. No need for a 10KOhm resistor for this part, but it is good practice in general. 2) I2C Ports - You are correct. The internal Pin header port has VDD5 on it, while the Grove connector gets 3.3V (or 5V - either will work) from the Pi. 2) I will fix the SunAirPlus2 documentation and republish today. My bad for being in such a hurry earlier this year. BP  |
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