FL2K_2 : a fork of the osmo_fl2K project.

Turns FL2000-based USB 3.0 to VGA adapters into low cost SDR-DACs. For more information on sorce see https://osmocom.org/projects/osmo-fl2k/wiki

We use the Fl2k adapter to be able to transmit independently on all three DAC channels of the Fl2k adapter while the original project only uses the Red-Channel.

The original project fork was primarily used for playing TBC files, see https://github.com/vrunk11/fl2k_2

Setup

Linux

Download Dependencies

sudo apt-get install libusb-1.0-0-dev

Install the libusb headers if not already present

git clone https://github.com/BM45/fl2k_2_rgb

cd fl2k_2_rgb

mkdir build

cd build

cmake ../ -DINSTALL_UDEV_RULES=ON

make -j 3

cd src

sudo cp fl2k_* /usr/local/bin

Before being able to use the device as a non-root user, the udev rules need to be reloaded:

sudo udevadm control -R

sudo udevadm trigger

Usage

As its an VGA R-G-B adapter so there are 3 DAC's

To transmit on all 3 DACs, you'll first need to create broadcast files for each channel using a tool like GNU Radio.

All files must have the same samplerate!

Examples:

To send an RF broadcast file on the Red Channel:

./fl2k_file2 -u -s 7777777 -R8 -R r_out.bin -VmaxR 0.7 -not_tbcR

To send an RF on Red and Blue Channel

./fl2k_file2 -u -s 7777777 -R8 -R r_out.bin -VmaxR 0.7 -not_tbcR -B8 -B b_out.bin -VmaxB 0.7 -not_tbcB

To send RF on all 3 DACs

./fl2k_file2 -u -s 7777777 -R8 -R r_out.bin -VmaxR 0.7 -not_tbcR -G8 -G g_out.bin -VmaxG 0.7 -not_tbcG -B8 -B b_out.bin -VmaxB 0.7 -not_tbcB

Commandlist and explanation

-d device_index (default: 0)

-readMode (default = 0) option : 0 = multit-threading (RGB) / 1 = hybrid (R --> GB) / 2 = hybrid (RG --> B) / 3 = sequential (R -> G -> B)

-s samplerate (default: 100 MS/s)

-u Set sample type to unsigned

-R filename (use '-' to read from stdin)

-G filename (use '-' to read from stdin)

-B filename (use '-' to read from stdin)

-R16 (convert bits 16 to 8)

-G16 (convert bits 16 to 8)

-B16 (convert bits 16 to 8)

-not_tbcR disable tbc processing for input R file

-not_tbcG disable tbc processing for input G file

-not_tbcB disable tbc processing for input B file

-VmaxR maximum output voltage for channel R (0.003 to 0.7) (scale value) (disable Cgain and Sgain)

-VmaxG maximum output voltage for channel G (0.003 to 0.7) (scale value) (disable Cgain and Sgain)

-VmaxB maximum output voltage for channel B (0.003 to 0.7) (scale value) (disable Cgain and Sgain)

-MaxValueR max value for channel R (1 to 255) (reference level) (used for Vmax)

-MaxValueG max value for channel G (1 to 255) (reference level) (used for Vmax)

-MaxValueB max value for channel B (1 to 255) (reference level) (used for Vmax)

-resample resample the input to the correct output frequency (can fix color decoding on PAL signal)

Possible USB Issues

You might see this in Linux:

Allocating 6 zero-copy buffers
libusb: error [op_dev_mem_alloc] alloc dev mem failed errno 12
Failed to allocate zero-copy buffer for transfer 4

If so then you can then increase your allowed usbfs buffer size with the following command:

echo 0 > /sys/module/usbcore/parameters/usbfs_memory_mb

Falling back to buffers in userspace Requested sample rate 14318181 not possible, using 14318170.000000, error is -11.000000

When the end of the file is reached you will see in CLI:

(RED) : Nothing more to read

Also, to enable USB zerocopy for better I/O stability and reduced CPU usage:

echo 0 > /sys/module/usbcore/parameters/usbfs_memory_mb

And reboot. This was added to the kernel back in 2014. The default buffer size is 16.

Based off the osmo_fl2K project software.