THIS HAT HAS BEEN UPDATED TO REV 2.0 A dedicated header for interfacing with 1.8V I2C sensors/signals has been added along with dedicated bi-direction level-shifting circuitry. The existing I2C header now supports 3.3v and 5v sensors/signals. Both headers can be used simultaneously.

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.

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.

Includes female and male headers plus screw-terminals for each signal for maximum flexibility.

Translation hardware supports signal speeds up to 20MHZ, limited only by protocol and target device limitations.

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.

Small 6.5 x 3.7 CM footprint allows HAT to comfortably fit on any Raspberry PI, including the Zero and Zero-W.

I2C

• Dedicated header for 1.8v SDA/SCL signals
• Second header for 3.3v/5v devices
• Fully bi-directional SDA/SCL signal lines
• Integrated 3.3K pull-up resistors
• Supports connecting to multiple I2C devices simultaneously on both headers

UART

• Uni-directional Serial signals:
• TX0 -> OUT
• RX0 <- IN
• RTS -> OUT
• CTS <- IN
• Supports high-speed serial connections

SPI

• Uni-directional SPI signals:
• MOSI -> OUT
• MISO <- IN
• SCLK -> OUT
• CE -> OUT
• CE0 / CE1 Selection switch
• Supports connecting up to 2 SPI devices

POWER

• Onboard 1.8v regulator provides up to 300ma
• Raspberry Pi 3.3v regulator provides up to 500ma
• Raspberry Pi 5v line can provide up to 500ma

ASSEMBLY

This HAT comes as a kit for self-assembly with all SMD components pre-soldered. The HAT can also be ordered fully-assembled for a nominal fee by selecting the options on the right.

DOCUMENTATION

Design documents and sample Python scripts and Arduino sketches are available from my Github repository. See links below.