Combined ESP32C3 and iCE40 FPGA board
This project combines an Espressif ESP32C3HN4 SoC (which includes 4MB of flash in the package) with a Lattice iCE40 FPGA (either an iCE5LP4k or iCE40UP5k or other pin an package-compatible devices) to allow WiFi and Bluetooth control of the FPGA. ESP32 and FPGA I/O is mostly uncommitted except for the pins used for SPI communication between ESP32 and FPGA. Several of the ESP32C3 GPIO pins are available for additonal interfaces such as serial, ADC, I2C, etc.
This project comprises both hardware, firmware, gateware and host-side communication utilities.
The hardware design is provided as schematic and layout in KiCAD 6 format. The design provides:
- Three standard PMOD connectors spaced to accomodate dual-PMOD modules with all eight signal pins directly connected to the FPGA.
- Additional I/O connector with seven ESP32C3 GPIO lines and one FPGA line, along with power and ground connections.
- USB-C connector for power, programming and JTAG debugging.
- LiPo Battery operation and charging.
- PCB antenna for WiFi and Bluetooth.
The ESP32 firmware is written in C with the ESP-IDF V5.0 toolchain and libraries. Initially it provides a TCP socket interface over WiFi with the following features:
- Initial loading of the FPGA configuration at powerup from a SPIFFS filesystem contained in the ESP32C3HN4 flash.
- WiFi socket-based "instant" loading of configurations direct to the FPGA.
- WiFi socket-based updating of the configuration stored in SPIFFS.
- WiFi socket-based monitor/control of the FPGA design via SPI.
The iCE40 FPGA gateware provided is a simple design that demonstrates basic SPI monitor/control via SPI with a flashing LED. More advanced designs are possible.
A command-line Python script is provided to communicate over TCP sockets with the ESP32C3 which supports the features outlined in the Firmware section above.
PCBs from the first revision are back from the board house and I've built one up. A few minor issues were discovered that had easy work-arounds, as well as a bug in the firmware configuration process. All essential parts of the project are tested out and working now and I've got the changes for a second revision ready to roll.
We're looking at a "community-base" upgrade to the project now. Lots of changes:
- Switching to a C3 Mini module that's pre-certified and less cost & hassle than the discrete approach of this design.
- Revising the PMOD pinouts to support higher-performance.
- Adding source termination to all PMOD I/O to reduce EMI.
- More tweaks TBD.
Find it here: https://github.com/mwelling/ICE-V-Wireless