Counter/statistics (number of TX packet, RX packet, etc.) in FPGA is offered via side channel register write/read.
The 1st step is alway loading the side channel kernel module:
insmod side_ch.ko
The register write command is:
./side_ch_ctl whXdY
X -- register index
Y -- decimal value to be written
./side_ch_ctl whXhY
X -- register index
Y -- hex value to be written (useful for MAC address)
Write register 26~31 with arbitrary value to reset the corresponding counter to 0.
The register read command is:
./side_ch_ctl rhX
X -- register index
The register 26~31 readback value represents the number of event happened. Each register has two event sources that can be selected via bit in register 19.
| register idx | source selection reg19 | event |
|---|---|---|
| 26 | reg19[0] == 0 | short_preamble_detected |
| 26 | reg19[0] == 1 | phy_tx_start |
| 27 | reg19[4] == 0 | long_preamble_detected |
| 27 | reg19[4] == 1 | phy_tx_done |
| 28 | reg19[8] == 0 | pkt_header_valid_strobe |
| 28 | reg19[8] == 1 | rssi_above_th |
| 29 | reg19[12] == 0 | pkt_header_valid_strobe&pkt_header_valid |
| 29 | reg19[12] == 1 | gain_change |
| 30 | reg19[16] == 0 | ((fcs_in_strobe&addr2_match)&pkt_for_me)&is_data |
| 30 | reg19[16] == 1 | agc_lock |
| 31 | reg19[20] == 0 | (((fcs_in_strobe&fcs_ok)&addr2_match)&pkt_for_me)&is_data |
| 31 | reg19[20] == 1 | tx_pkt_need_ack |
Note: fcs_in_strobe means decoding is done (not necessarily CRC is correct); fcs_ok 1 means CRC correct; fcs_ok 0 means CRC not correct.
Note: addr2_match means addr2 matches to the register (addr2_target) value; pkt_for_me means addr1 matches self mac addr; is_data means the packet type is data.
Configuration register:
| register idx | meaning | note |
|---|---|---|
| 7 | addr2 target value | fcs event always needs addr2 match |
| 9 | threshold for event rssi_above_th | check auto_lbt_th in ad9361_rf_set_channel of sdr.c to estimate a proper value |
Note: addr2 (source/sender's MAC address) target setting uses only 32bit. For address 6c:fd:b9:4c:b1:c1, you set b94cb1c1
Note: read register 62 of xpu for some addr2 captured by the receiver