OpenHT-hw

Hardware part of the OpenHT - an open-source, SDR handheld transceiver.

Description

The device is a complete, low RF power I/Q transceiver, supporting virtually any mode (including M17 and FreeDV). It is built around the AT86RF215 chip by Microchip/Atmel and LIFCL-40-9SG72C FPGA from Lattice as a shield for 32F469IDISCOVERY. It is possible to use the board with other MCU platforms.

Technical details:

• frequency range: 389.5 - 480, 2400 - 2483.5 MHz (RX, TX frequency range is limited by your local laws)
• RF power output: <14dBm (<25mW)

Assembly tips and U204 issue

After the board has been populated, perform the steps below:

1. Remove JP201 (undervoltage lock-out).
2. Remove U204 (you need to take the lower shield off).
3. Using a copper wire, connect VIN and VBAT.
4. Secure goldpin headers in place by putting them on the DISCO board (Arduino male connector and the 2x8 female connector) and solder them.
5. Populate JP401 and short the two left pins,JTAG_EN to GND, "OFF" position.
6. Prepare a micro-SD card with the FPGA image, its filename should be OpenHT_impl_1.bit. The SD card has to be preformatted with FAT32.
7. Plug the mini-USB port and flash the firmware from the main branch.
8. In the GUI, tap on the cog icon (upper left corner), then press the Erase NOR button. After a few seconds (about 3), press the SD to NOR button and wait a few seconds more.
9. After the flashing is done, press and hold the power-on button for at least 1.5 seconds. The "LED" next to the cog icon should light up in green.

Step 8) needs to be performed only once for a fresh FPGA image. After that, the image is transferred to the NOR flash and is supposed to be retrieved by the FPGA automagically. It is highly recommended to use terminal for getting debug info. The terminal is 115,200 baud, 8n1, over the COM port exposed by the DISCO board.