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nRF24 / CircuitPython_nRF24L01

CircuitPython driver library for the nRF24L01 transceiver.
http://circuitpython-nrf24l01.rtfd.io/
MIT License
45 stars 11 forks source link

Possible to change the SPI bus speed on RPi before creation of RF24 object #15

Closed dsilva-vd closed 4 years ago

dsilva-vd commented 4 years ago

@2bndy5 Our application uses the nRF24 module but because we have the module on the end of a long cable we had to change the SPI bus speed. The popular RF24 library (version 1.3.8) allows for the SPI bus speed to be set when creating the class i.e. RF24(CSN, CE, <SPI Bus speed>). Is there some way to do this with the module you wrote? Or does the CircuitPython's board module allow this to be done?

2bndy5 commented 4 years ago

I actually already added this arg to the c'tor on my latest branch (forgot to document it though). The branch isn't released yet but you could try it out right now using pip3 install git+https://github.com/2bndy5/CircuitPython_nRF24L01@lite-beta. Its a very stable branch, but PA/LNA modules are have trouble TXing (might be a hardware issue about higher power requirements)

2bndy5 commented 4 years ago

sorry kwarg to the c'tor is named spi_frequency

2bndy5 commented 4 years ago

its now documented

2bndy5 commented 4 years ago

I can confirm that the spi_frequency kwarg in the c'tor works. Apparently "long" wires mean anything longer than a couple inches. I ran into the same problem you described on my Feather M0 Express board when testing the rf24_lite.py module (designed specifically for that ATSAMD21 CPU). Using the default SPI speed (10 MHz), I would get weird data returned from SPI transactions (some write operations wouldn't take either), but lowering it to 2.5 MHz solved it. @dsilva-vd thank you for this insight!

2bndy5 commented 4 years ago

@dsilva-vd I'm closing this issue because I just released v1.2.0 to pypi.org which includes the requested constructor argument. If have any other questions or suggestions I'm eager to discuss them in another issue. Thank you again for your input.