EsPiFF is a rock-solid Raspberry Pi replacement for applications that do not require the processing power of a Pi or the versatility of Linux but that do require extreme reliability. Pis are great for video, firewall, and NAS applications, but they don’t always provide the level of stability needed for 24/7 applications like home- and industrial-automation deployments. EsPiFF is optimized for uptime, thanks to a supervisor, a super-cap-buffered external real time clock (RTC), an external reset generator, an external watchdog, 8 Mbit of high-end ISSI flash storage, and 2 KB of FRAM for permanent, high-speed, storage for process variables.

And of course, the global chip crisis has made it quite difficult to source Raspberry Pis, so EsPiFF represents a viable alternative for different kinds of projects.

Reuse Existing Raspberry Pi Accessories

EsPiFF packs an RP2040 on board, which enables the use of existing Pi HATs. The RP2040 state machines allow you to use any protocol via the 40-pin header. 100-MHz signals on your HAT pins? No problem. The RP2040 can handle that. Paired with 16 MB of flash storage, it combines the speed of an FPGA with the simplicity of a SDK-, Arduino-, or Python-programmable MCU.

EsPiFF also fits in third-party Raspberry Pi enclosures, allowing you to choose from a wide array of options, from DIY print-at-home cases to plastic to metal to DIN rail to whatever else the Raspberry Pi community has made available.

Ethernet, Wi-Fi, Bluetooth, and Serial Communication

EsPiFF is made for communication. It provides wired Ethernet, Wi-Fi, Bluetooth, USB host and device modes, and up to three UART connections. It supports external Wi-Fi antennas, as well, which makes it compatible with all kind of plastic and metal enclosures. We are shipping each EsPiFF unit with an external Wi-Fi antenna.

Flexible Storage, Efficient Processing, and No Heat-Dissipation Issues

EsPiFF comes with 16 MB of flash built into the module, and we’ve added 8 Mbit of on-board external flash as well as an (unpopulated) footprint for up to 512 Mbit of additional high-end ISSI flash storage. And of course, you can use the SD card reader to extend this capacity even further. The ESP32’s dual 240-MHz CPUs have access to 8 MB of PSRAM, and EsPiFF is so thermally efficient that you could place it in a water- or air-tight enclosure and it would continue to operate in a way that would be impossible for a Raspberry Pi.

Features & Specifications

• ESP32-WROVER with 8 MB PSRAM and 16 MB Flash in a Raspberry Pi 4 form factor
• 2 KB of fast FRAM for permanent storage of process data. (Much faster then EEPROM, for key variables.)
• 8 Mbit state-of-the-art ISSI flash
• Unpopulated footprint for up to 512 Mbit state-of-the-art ISSI flash
• Wi-Fi connectivity (requires an external U.FL antenna)
• 10/100 wired Ethernet via IP101 PHY
• PoE header, to use Raspberry Pi PoE HATs. EsPiFF can be powered from a HAT or can power the HAT
• Micro SD card socket for storage
• Up to 3 UARTs
• USB Type-C connector on CH340 USB-UART for programming as well as power draw up to 5 V / 3 A for power-hungry HATs
• 40-pin Raspberry Pi header, compatible with all Raspberry Pi HATs
• RP2040 co-processor to emulate the Pi on the 40 pin connector, with 16 MB Flash
• External realtime clock, watchdog, and supervisor for high-availability, 24/7 applications
• On-board supercap to keep the realtime clock running for days, even without power. The supercap has, in contrast to a battery, a practically infinite lifetime
• USB-Host on the USB Type-A connector
• BOOT button for the RP2040, to switch between USB-Programming and USB-Host/Device
• ESP32 reset button and three user LEDs
• Unpopulated JTAG header for kernel developers

Comparisons

Board Layout

Support & Documentation

EsPiFF is fully open source and you can find our design files on GitHub, along with our datasheet. EsPiFF runs Apache NuttX RTOS, or you can program it with Espressif IDF, Arduino, and other ESP32 development tools.

Manufacturing Plan

We will be working with a manufacturing partner in China, who will handle fabrication of the EsPiFF PCBs and as assembly for most components. We have worked with this partner for a long time—including on previous versions of EsPiFF—and have been consistently pleased with their professionalism, quality, and efficiency. We will do final assembly and testing in house.

Support & Logistics

After our production run is complete, we will box everything up and send it along to Crowd Supply’s fulfillment partner, Mouser Electronics, who will handle distribution to backers worldwide. You can learn more about Crowd Supply’s fulfillment service under Ordering, Paying, and Shipping in their guide.

Risks & Challenges

We have designed and produced several products, and that experience has taught us valuable lessons about every stage of the process. When it comes to our BOM, for example, we use consistently available components wherever possible, we source critical parts in advance, and we identify alternatives, to name just a few of the best practices we employ.

While there are no pin-compatible equivalents for three of our ICs—the ESP32 module, the RP2040, and the IP101—these parts have been consistently available throughout the past two years, despite the chip shortage. We do not anticipate any difficulty sourcing them. Furthermore, should the IP101 become unavailable, we are prepared to design an alternative layout to accommodate the RTL8201, what is functionally identical but has a different footprint.