Colorado-based embedded electronic device manufacturer, SparkFun, has announced the commercial availability of the Thing Plus Dual-Port Logging Shield. Due to its Thing Plus form factor, the device is easily compatible with the existing modules and sensors available on the market. At present, there are several data logging embedded devices, like the OpenLog Artemis and Qwiic OpenLog that require the microSD card to be popped out and plugged into a computer in order to read the logged data. But this can become a problem when the developer is building an embedded systems application and cannot eject the microSD card. SparkFun provides the solution through its new Dual-Port Logging Shield, which solves this problem by providing easy access to the microSD card data through both SPI and the USB Type-C port.
At the heart of the board is the ATtiny841 microcontroller, which allows the system designer to optimize power consumption versus processing speed by achieving throughputs approaching 1 MIPS (million instructions per second) per MHz. The onboard microcontroller acts as an arbiter, that is the ATtiny841 will automatically put the Dual-Port Logging Shield into SPI mode if the developer powers up the Thing Plus. This enables the Arduino code to easily access the microSD as if the shield were powered from the computer by connecting it via the USB-C and the ATtiny841 microcontroller puts the shield into SDIO “thumb drive” mode.
The ATtiny841 microcontroller can be configured automatically to SPI mode or SDIO “thumb drive” mode if one can power up the Thing Plus and get the computer connected simultaneously. Furthermore, this simplifies switching between the two modes and this can be achieved by giving the ATtiny841 some simple commands over I2C.
The board is designed to be mounted on or under one of the Thing Plus boards. By making use of the Arduino SD libraries, logging and reading data to and from the microSD card respectively is possible over SPI. You can also read and write files at up to 35MBytes/second by connecting the microSD card to the computer via a USB Type-C port. In addition, the board provides the USB2241 Ultra-Fast USB 2.0 Media Controller which supports FAT32, exFAT, and NTFS. It also provides support for cards up to 32GB.