So this board...
Works fine on breadboard. It's an ATMega328p with an ESP12.
The goal is to use the ATMega to write sensor data (temp, humidity etc) to the EEPROM on the RTC module and then go to sleep every minute (or 5 mins or...).
Every 10 mins (or 20 mins etc) I want the ESP12 to wake up, become the I2C bus master (yes funky I know but I've found ways to do it here https://www.hackster.io/chipmc/arduino-i2c-multi-master-approach-why-and-how-93f638), read the data in the EEPROM and dump it via MQTT.
The reason for doing all of this is battery consumption. I want to use uA when sleeping and low mA when reading sensors. I want to be able to control how/when the esp12 wakes up.
As noted above, this all works fine on breadboard. When transferred to a PCB, it's all goes pear shaped..really odd behavior, atmega crashing, I think I've blown the atmega in the latest build and it looks like i've shorted gnd and vcc and yet it's not a soldering problem i can see (i've been doing SMD for a while and it's normally fine).
There's no voltage regs, but powering from a LiFePO4 battery or a bench top PSU yields similar results.
I'm thinking my ground pours might be to blame, not enough isolation perhaps ? I'm using PCBWAY as the manufacturer, but following OSHParks settings. Everything passes DRC and ERC in Kicad.
I'm stumped, any comments or critiques welcome...