ESP32 Forum

I am interested in building a board with more interfaces than a single ESP32 can accommodate. I could get there with several fanout devices but that approach seems too complex and difficult to code around. An alternative would be placing two or more ESP32 devices on the same board and using SPI or some wired interface to communicate between them. I have seen references to ESP_NOW to have multiple devices communicating over Wi-Fi, but I prefer a wired interface because I fear motor bridge driver noise sources in my application may make those connections occasionally unreliable. What is recommended for such applications? Do software drivers exist for multiple ESP32 instantiations exclusive of ESP_NOW and Wi-Fi?

Kinda confused here.

I could get there with several fanout devices but that approach seems too complex and difficult to code around.

An SPI or I2C to GPIO device is far simpler than adding multiple ESP32's and trying to get all them talking to one another.

My current single ESP32 architecture has four devices on a shared SPI interface with one of those being a UART expander to two more interfaces and another to full speed Ethernet. I have four devices on I2C with one of those being a port expander to accommodate at least 8 signals. I have two dedicated PWM interfaces and a few miscellaneous GPIOs. I am concerned about the potential for buffer overflow with all these shared interfaces. It seems like spreading the load across more devices with direct links to more storage and quicker access to interrupt response would be better from a system perspective.

I'm also curious as to whether such ESP32 to ESP32 wired communication is available - for similar reasons.

Whilst I'm sure we could engineer something custom - perhaps over SPI or I2C or "weird" as you say - but very curious as to whether there is something already available or which could be re-purposed to achieve the same. Looking to do high speed, large transfers from one (or two) ESP32;s to another on the same PCB without relying on a wireless link (indeed having two or three WiFi devices side by side seems almost tempting some kind of mutual interference or at minimum, is sheer overkill with latent unreliability in the face of a noisy of and potentially jammable environment )...

Not looked closely yet but I assume the ESP32 AT over SDIO allows this? Or is that that mainly for a different scenario?