Open source board lets you analyze SPI connections on a USB-connected laptop
Jun 18, 2018 — by Eric Brown 1,824 viewsExcamera Labs has launched an open source, $27 and up “SPIDriver” board on Crowd Supply for analyzing and testing SPI-connected displays, sensors, flash, and other components on a laptop or via a built-in color LCD display.
Monitoring SPI devices such as LCD panels, LED arrays, sensors, and SPI flash may not be quite as gnarly as managing I2C gizmos, but either of these short-distance, serial data transfer protocols can be a hassle. While Arduino boards provide libraries for SPI monitoring, there’s still a lot of guesswork involved due to lack of real-time feedback about the SPI bus state.
Pescadero, Calif. based Excamera Labs aims to streamline the SPI interface with an SPIDriver board designed for hackers and computer educators alike. Excamera Labs has met its Crowd Supply funding goals for the board, which lets you monitor the performance of SPI devices on a laptop screen.


SPIDriver Core (left) and connecting to LED strip
(click images to enlarge)
The fully open source SPIDriver uses a standard FTDI USB serial chip to connect SPI based devices to a PC via a micro-USB connection. The SPIDriver works with most SPI-connected displays, including Gameduino touchscreens, and can also be used to control an LED array.
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The board supports Windows, Mac, and Linux computers. Yet, in an email, Excamera’s James Bowman said the BSD-licensed SPIDriver is “a Linux-first project, all built on Linux and tools aimed at Linux makers.”
The basic, $27 SPIDriver Core version provides a 61 x 49mm SPIDriver board with the serial/USB connector on one end and hookup jumpers on the other that support SPI transfers at 500Kbps. The board runs on a Silicon Labs “automotive-grade” EFM8 controller and provides a 470 mA power supply with support for 3.3V and 5V signals. You also get voltage and current monitoring and a high-side current meter.
Color-coded wires are said to enable a correct connection without consulting a pinout. A temperature sensor is also available.


SPIDriver Expert with Arduino Pro (left) and Gameduino display
(click images to enlarge)
Most buyers will likely go with the $57 SPIDriver Expert model, which adds an Arduino-style SPI adapter for connecting to Arduino boards, as well as a 160 x 128-pixel LCD that shows a live logic-analyzer display of all connected SPI traffic. The Expert model also supplies an in-circuit flash programming clip that lets you read, backup, and restore standard SPI flash chips in-circuit. The flash function is supported by the flashrom tool.
A $69 SPIDriver Gold package adds to the Expert features by offering custom programming of the board’s USB serial ID with an 8-character name of your choice. All the models are available through July 13 and will ship Aug. 24.
The SPIDriver can be installed without loading a driver. The software gives you interface choices including a GUI, the command-line, C and C++ via a single source file, and support for Python 2 and 3, “using a module,” says Excamera.
Further information
The SPIDriver board is available on Crowd Supply through July 13 starting at $27, with shipments due Aug. 24. More information may be found on the SPIDriver Crowd Supply page and the Excamera Labs website. There’s also a GitHub page.
Choice is never a bad thing, but for $50 one can get an actual 200MHz sampling logic analyzer (the Openbench Logic Sniffer) which will show (and trigger on) a heck of a lot more than the last 3-4 bytes and isn’t SPI-specific…