C. Burgess, of BurgessWorld Custom Electronics, has launched a new HAT accessory for the Raspberry Pi family of single-board computers, which offers uni- and bi-directional level shifting across to 1.8V, 3.3V, or 5V external hardware.
"This HAT allows your Raspberry Pi to communicate with other devices at 1.8V, 3.3V, or 5V levels. Can be used to connect to sensors, other microprocessors, communications lines, etc.," Burgess explains. "[It] provides bi-directional and uni-directional automatic level-shifting for SPI, UART/Serial (including RTS/CTS signals), and I2C connections. Output voltage-level can be set per-protocol. For example, you can communicate with an Arduino at 5V, an I2C sensor at 1.8V, and an SPI device at 3.3v, all at the same time."
Building on an earlier design, Burgess' second revision offers a few upgrades. There's a dedicated header for interfacing with 1.8V I2C sensors, along with dedicated bi-directional level-shifting circuitry, and the existing header supports both 3.3V and 5V signals — with both headers being able to operate simultaneously for a mix of 1.8V, 3.3V, and 5V hardware.
"Translation hardware supports signal speeds up to 20MHz, limited only by protocol and target device limitations," Burgess adds. "Selected output voltage plus ground connections available at I2C and SPI headers to allow you to power external sensors directly from the HAT. RTS/CTS signals available on the Serial header to allow for communicating with a wide-range of devices."
The board is now available on the BurgessWorld Tindie store for $21.95 as a do-it-yourself kit, with a $5 premium for a fully-assembled version — plus an extra $3 to bundle stackable headers.