EspressoCM

Espresso Rev 4 CM, or just Espresso CM, is an STM32- and ESP32-based compute module for high performance networking and automation applications. The board was designed to provide a plethora of capabilities in a small, user-friendly and cheap package. An STM32 and two (not one but two!) ESP32's were chosen for their ease-of-use, clock speed and peripherals to acommodate these requirements. For the beginner or novel hobbyist, the ESP32's can be used - both come with their own dedicated flash memory chip as well as Wi-Fi and Bluetooth connectivity. For the more advanced and tech-savy, the STM32 can be programmed directly for higher-performance control.

Link to EspressoCM's complimentary library: https://github.com/discount-cactus/EspressoCMlib

Board Statistics

• Dimensions: 84.9mm x 50.2mm
• Layers: 4
• Components: 83
• Mounting Hole Size: M2

Features

• 1 x STM32F107 (@72MHz)
• 2 x ESP32-S3 (@240MHz)
• 1 x ATtiny85
• 1.5A linear regulator (VIN: 3-20V)
• Automatic power switchover from terminal block J7 and JST battery connector J8
• JST LiPo Battery Connector
• 128Mbit Flash (one per ESP32)
• Dedicated E2B functionality
• On-board current sensing

Applications

• Smart Homes
• Home networks
• IoT Connectivity
• Home automation
• Sensor monitoring

Programming

STM32

• The STM32 is programmed on-board via the pin connector J5 with an ST-Link V2.
• Verify STM32CubeIDE is up-to-date
• Verify ST-Link V2 is up-to-date

1. Set BOOT0 to HIGH
2. Push reset button
3. Build code
4. Run code
5. Set BOOT0 to LOW
6. Push reset button

ESP32

• The ESP32's are programmed on-board via the header pins J3 (for Core 1) and J4 (for Core 2). Pins are labeled on silkscreen.

ATtiny85

• The ATtiny85 is programmed off-board.