Electronics > Microcontrollers

[SOLVED] SPI Sdcard + I2C Sensor = No go!

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radhoo:
Heya folks!

Not my first post on crazy voodoo wasting precious time, like it happened some time ago.

This time, things are different. I'm working on the uRADMonitor model D, to summarise it is 60x110cm board with an Atmega2561, a 2500mAh battery, two inverters based on LTC3440 for 3.3V / 5.0V used independently, a TP4056 battery charger,  a DS1337 RTC (I2C), an EEPROM (I2C), a FT232 USB2Serial, a software configurable high voltage inverter with multiplier (configured for 480V), a microSD slot (SPI), a NEO6M GPS (UART), a ESP8266-ESP03 Wifi board (UART), a Bosch BME680 (I2C) and a Sharp gp2y1010au0f and an ILI9341 2.4" LCD (SPI) with touchscreen.

After several changes and revisions:


I finally got to the fifth variant which was good enough. I assembled two PCBs and done all the software: drivers for the various modules and sensors, a fat32 implementation for the sdcard, a gps nmea parser, an lcd driver with a minimalistic library, etc, etc. So everything worked just fine.
I pushed it to production, not before doing some changes to the PCB layout, nothing fancy, just moving the speaker a little and adjusting the size of the SMD pads. So the factory finished the assembly of a few devices, but the test software fails.

Here's the Voodoo part:
1. If my code inits the BME680 (over I2c) and tries to write something to the SDCard, the device will NOT start, nothing, not even some innocent code just writing something on the screen.
2. If I take out the BME680 init code,and the read function, the code can write to the SDcard just fine and all the code works, for all the modules and components.

This behaviour is not happening on my two assembled test units. I suspect the following:
1. Different Atmega2561 with some weird memory issues (unlikely)
2. Code memory corruption (unlikely) - the code is nothing but a collection of personal libraries for all the modules used.

Testing goes slow, as it is done remotely on the route Romania - China factory.

Any suggestions on how could this be addressed remotely?

Thanks!

Fortran:
Are you running the 2561 on 3.3V?
Because they're available in two voltage ranges. 
Atmega2561V-xx  1.8V - 5.5V
Atmega2561-xx 4.5V - 5.5V

Fortran:
Are you sure? :)

Atmega2561-16AU has a specified input rating of 4.5V to 5.5V.
3.3V is below that.

Going outside the specified rating even a little means basically anything can happen.
The ones you have that are working might be doing so just out of pure luck.

radhoo:
I had to delete previous reply because it was wrong.

So to put everything in order: the latest version is using mega2561-16AU running on 3.3V  |O . Long story short, initially it was an mega128, that got upgraded to the 2561. When selecting this IC I did a mistake, as per the picture attached.

Thanks for the second pair of eyes on this, Fortran. I will investigate this direction and report back.

Radu

Someone:
You say the tube is alpha sensitive, but then how are you applying the biological weighting for the sievert? The data sheet for the tube doesnt show a reduced sensitivity to account for any weighting in the window. It would be very misleading to present that measurement if its only based on a single isotope.

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