I am making a physical baseball game, with players running to bases around the field depending on how great a shot is. I've used up all of my GPIO pins on my ATMega328p, and was wondering how i can connect two atmegas together. I need to send the data for the shotquality to the slave, which then uses that data to determine how far a stepper motor should step.
I have 4 steppers, one to move a player between each base, with each hooked to a driver for controlling them.
Since im not in need of fast data transfer between each device, im not sure whether i should use I2C or SPI, and i haven't quite figured out how to use the different techniques.
This is one of the first bigger projects i have made, and any help would be great.
Welcome to the forum
Have you used all of the analogue input pins ?
You can't use either, if you have already used all the GPIOs, since I2C and SPI use GPIO pins.
Please post a complete wiring diagram (hand draw is fine), with all pins and connections clearly labeled.
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You don't mention how you have used the GPIOs. Some are for the steppers but for other stuff you can consider using shift registers or I2C/SPI port expanders for digital IO and analogue multiplexers for analogue inputs.
It will more than likely be easier than creating a solid communication protocol between two 328P processors.
I’m assuming the processors are separated by some distance. Have you considered using CAN (Controller Area Network)? It’s well-suited for communication over longer distances and is designed to handle robust and reliable communication between processors in complex systems.
That would be the hardest way to solve your problem. Use a pin expander IC and it will be much easier. Turn the two I2C pins into 8, 16, or more digital pins.
Search for MCP23017
Move your code to a board with more I/O pins such as a MEGA board. It is easier to use a Clydesdale than harness a bunch of Shetland ponies together.