FFT evaluation

DESCRIPTION

This program has been created to aid open source spectrum analyzer development for Qualcomm/Atheros AR92xx and AR93xx based chipsets.

It visualizes the FFT data reported by the chips to help interpreting and understanding the data.

TODO: The interpreted data format is unknown! Please help investigating the data, or help acquiring information about the data format from Qualcomm Atheros!

BUILD

You need to have SDL2 and SDL2_ttf development packages installed on your system, as well as make and gcc.

Just type make to build the program:

$ make
gcc -O2 -Wall -pedantic -c -o fft_eval.o fft_eval.c
gcc -lSDL2 -lSDL2_ttf -o fft_eval fft_eval.o
$

USAGE

First, you need to acquire sample data from your spectral-scan enabled Atheros WiFi card. If the patches are applied correctly, you can use the following commands:

For ath9k/AR92xx or AR93xx based cards, use:

ip link set dev wlan0 up
echo chanscan > /sys/kernel/debug/ieee80211/phy0/ath9k/spectral_scan_ctl
iw dev wlan0 scan
cat /sys/kernel/debug/ieee80211/phy0/ath9k/spectral_scan0 > samples
echo disable > /sys/kernel/debug/ieee80211/phy0/ath9k/spectral_scan_ctl

For ath10k/AR98xx based cards, use:

ip link set dev wlan0 up
echo background > /sys/kernel/debug/ieee80211/phy0/ath10k/spectral_scan_ctl
echo trigger > /sys/kernel/debug/ieee80211/phy0/ath10k/spectral_scan_ctl
iw dev wlan0 scan
echo disable > /sys/kernel/debug/ieee80211/phy0/ath10k/spectral_scan_ctl
cat /sys/kernel/debug/ieee80211/phy0/ath10k/spectral_scan0 > samples

For ath11k based cards, use:

ip link set dev wlan0 up
echo background > /sys/kernel/debug/ieee80211/phy0/ath11k/spectral_scan_ctl
echo trigger > /sys/kernel/debug/ieee80211/phy0/ath11k/spectral_scan_ctl
iw dev wlan0 scan
echo disable > /sys/kernel/debug/ieee80211/phy0/ath11k/spectral_scan_ctl
cat /sys/kernel/debug/ieee80211/phy0/ath11k/spectral_scan0 > samples

There are some recorded samples in the "samples" directory to try it out without actual hardware.

To view the FFT results, use:

./fft_eval_sdl /tmp/fft_results

Navigate through the currently selected datasets using the arrow keys (left and right). Scroll through the spectrum using the Page Up/Down keys.

LICENSE

Read the GPL v2 file 'COPYING'.

AUTHOR