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Rodemfr / MicronetToNMEA

A NMEA 0183 converter for Raymarine's wireless instruments ... and much more !
GNU General Public License v3.0
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Lowering SPI clock #19

Closed dwarning closed 1 year ago

dwarning commented 1 year ago

I used lower SPI clock in freq_tracking branch 2MHz. With that no delays are needed in CC1101 operation. Checked this with 3.6 and 4.1 board. In my opinion something is wrong in their 4.x SPI driver. Make an side by side compare of the attached CC1101Driver file. True burst is not needed but gives few time saving in first FIFO access. CC1101Driver_cpp.txt CC1101Driver_h.txt

Rodemfr commented 1 year ago

Using true burst is a good idea. I will make the change. Lowering the SPI clock is more tricky because this increases the time of SPI transactions and thus reduces the CPU available all the transfers being synchronous. I prefer to keep the SPI at 4MHz with dedicated delays where needed. There is something interesting in your modified CC1101 driver : you chose to use SpiStart/SpiEnd at each transfer instead of keeping it in init/termination methods. Technically I think your way of doing is conforming to the spec, however, this as proven to make the porting on ESP32 fail because of the very long processing time of these functions on the ESP32 multicore platform. I don't really know what could be the best here. I still have in mind the idea of resuming ESP32 porting now that we have a rewritten CC1101 Driver.

dwarning commented 1 year ago

Oh, that's too old. Can't follow any more. Made few observations with scope in that time.

Regarding esp32 cc driver: Did you ever take a look into tty's code esp32micronet on github?

frgaude commented 1 year ago

with regard to esp32. I took your work (master from a month ago) and tried to get the traffic scanning part to work... and it works with very minor changes (I can't really code and I have no electronics background). my work is very rough (EEPROM not working, my settings are hardcoded, and I only kept the scanning part) but it is just to share that the radio/cc part just works on ESP32.

Rodemfr commented 1 year ago

I think the most difficult part will probably be related to CC1101 transmission since it needs precise HW timer. esp32micronet projet should help with this matter. The plan is to finish the work on the Teensy version (fixing bug, merging frequency shift algorithm) and then to go for the ESP32 port again.