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LoFive is a lightweight SiFive Freedom E310 open source SoC evaluation kit. The E310 leverages the Free and Open RISC-V Instruction Set Architecture originally developed by UC Berkeley and now has wide industry support via the RISC-V Foundation.
- MCU – SiFive Freedom E310 (FE310) 32-bit RV32IMAC processor @ up to 320+ MHz (1.61 DMIPS/MHz)
- Storage - 128-Mbit SPI flash (ISSI IS25LP128)
- Expansion - 2x 14-pin headers with JTAG, GPIO, PWM, SPI, UART, 5V, 3.3V and GND
- Misc - 1x reset button, 16 MHz crystal
- Power Supply - 5V via pin 1 on header; Operating Voltage: 3.3 V and 1.8 V
- Dimensions - 38 x 18 mm (estimated)
- License - CERN Open Hardware Licence v1.2
The Freedom-E SDK version that is ported for LoFive hosted here: LoFive Freedom-E SDK
Note: The instructions for installing and compiling the SDK are provided in the README of the repository.
The on-board flash is programmed via JTAG and a special RISC-V version of OpenOCD built into the Freedom-E SDK. LoFive currently supports using the FT2232H-56Q FTDI breakout adapter.
Wire the breakout adapter as follows:
| LoFive Pin | FT2232H-56Q Breakout Pin |
|---|---|
| +5Vin | VBS |
| GND | GND |
| TRSTN | AD5 |
| TCK | AD0 |
| TDO | AD2 |
| TMS | AD3 |
| TDI | AD1 |
| UART0.TX | BD1 |
| UART0.RX | BD0 |
This will power the board and allow you to program it with the LoFive enabled Freedom-E SDK linked above.
Once the SDK is installed and compiled you can load the code via make upload.
For instance to load the LED demo:
make upload PROGRAM=led_fade BOARD=freedom-e300-lofiveNote: This SDK only supports running on Linux.
Some of the early units of the LoFive may have been deployed without the bootloader installed. If a previously loaded program does not load automatically on reset or power cycle the bootloader is likely not installed.
To program the bootloader to the LoFive run the following from the Freedom-E SDK:
make software upload PROGRAM=double_tap_dontboot BOARD=freedom-e300-lofive-blank