This repo contains playground code for testing Near UltraSound (NUS) support on Simmel. It is designed to be used via a USB serial console.
This program is larger than the normal bootloader, so it will erase your existing bootloader as well as your circuit python install, so after you're done in the playground you will need to reflash the bootloader and reinstall circuit python.
To use the NUS playground, enter this directory and run the following:
$ git submodule init
$ git submodule update
$ make
$ arm-non-eabi-gdb _build/nus-test-nosd.elf -ex 'tar rem your-openocd-server:3333'
(gdb)You can then make changes and reload in gdb:
(gdb) make
(gdb) load
(gdb) mon reset halt
(gdb) continue
You can use the nus-harness to select frequency parameters that are conducive to this particular modulation algorithm. For example, to sweep through baud rates and filter widths, you might try running:
[3:03:42 PM] D:/Code/Simmel/nus-harness> cargo run --release -- --output ./log.csv --input ./test/rand.bin --baud 5000..49..5200 -r 62500 -h 17000 -l 15000 --filter-width 7..10
Finished release [optimized + debuginfo] target(s) in 0.17s
Running `target/release/nus-harness.exe --output ./log.csv --input ./test/rand.bin --baud 5000..49..5200 -r 62500 -h 17000 -l 15000 --filter-width 7..10`
Modulating ./test/rand.bin into ./log.csv.
Is update? false Data rate: High Protocol version: V2
PARAMETERS baud_rate: 5000 f_lo: 15000 f_hi: 17000 filter_width: 7 DEMOD 99/102 97.059%
PARAMETERS baud_rate: 5000 f_lo: 15000 f_hi: 17000 filter_width: 8 DEMOD 99/102 97.059%
PARAMETERS baud_rate: 5000 f_lo: 15000 f_hi: 17000 filter_width: 9 DEMOD 99/102 97.059%
PARAMETERS baud_rate: 5000 f_lo: 15000 f_hi: 17000 filter_width: 10 DEMOD 102/102 100.000%
PARAMETERS baud_rate: 5049 f_lo: 15000 f_hi: 17000 filter_width: 7 DEMOD 102/102 100.000%
PARAMETERS baud_rate: 5049 f_lo: 15000 f_hi: 17000 filter_width: 8 DEMOD 102/102 100.000%
PARAMETERS baud_rate: 5049 f_lo: 15000 f_hi: 17000 filter_width: 9 DEMOD 102/102 100.000%
PARAMETERS baud_rate: 5049 f_lo: 15000 f_hi: 17000 filter_width: 10 DEMOD 102/102 100.000%
PARAMETERS baud_rate: 5098 f_lo: 15000 f_hi: 17000 filter_width: 7 DEMOD 102/102 100.000%
PARAMETERS baud_rate: 5098 f_lo: 15000 f_hi: 17000 filter_width: 8 DEMOD 100/102 98.039%
PARAMETERS baud_rate: 5098 f_lo: 15000 f_hi: 17000 filter_width: 9 DEMOD 102/102 100.000%
PARAMETERS baud_rate: 5098 f_lo: 15000 f_hi: 17000 filter_width: 10 DEMOD 97/102 95.098%
PARAMETERS baud_rate: 5147 f_lo: 15000 f_hi: 17000 filter_width: 7 DEMOD 102/102 100.000%
PARAMETERS baud_rate: 5147 f_lo: 15000 f_hi: 17000 filter_width: 8 DEMOD 99/102 97.059%
PARAMETERS baud_rate: 5147 f_lo: 15000 f_hi: 17000 filter_width: 9 DEMOD 102/102 100.000%
PARAMETERS baud_rate: 5147 f_lo: 15000 f_hi: 17000 filter_width: 10 DEMOD 90/102 88.235%
PARAMETERS baud_rate: 5196 f_lo: 15000 f_hi: 17000 filter_width: 7 DEMOD 88/102 86.275%
PARAMETERS baud_rate: 5196 f_lo: 15000 f_hi: 17000 filter_width: 8 DEMOD 55/102 53.922%
PARAMETERS baud_rate: 5196 f_lo: 15000 f_hi: 17000 filter_width: 9 DEMOD 98/102 96.078%
PARAMETERS baud_rate: 5196 f_lo: 15000 f_hi: 17000 filter_width: 10 DEMOD 64/102 62.745%
[3:03:42 PM] D:/Code/Simmel/nus-harness>From this output, you would know that 5049 baud is an ideal baudrate for this algorithm with the given F_LO and F_HI, and the filter_width can be made as low as 7.
These parameters can be set inside src/main.c in the struct nus_config cfg definition.