Hello,
I have problems connecting an Arduino Pro Mini 3.3V/8Mhz to a nRF24L01 SPI module and I was thinking if it could have something to do with the MCU frequency of 8Mhz.
It fails right at the begining, when connecting wit the module with radio.begin(). It returns false and in the printing the debug details all registers are zero, so the Arduino can't communicate with the nRF24L01module.
In the 1st row its says: "SPI Speedz = 10 Mhz" That's why I think it could be problem. Then I have try to initialize it with 8Mhz, 4Mhz or 2Mhz and doesn't work neither. RF24 radio(9, 10, 4000000); // CE, CSN, freq in Hz
The same module and same exact program and wiring works fine with an Arduino Uno. And also with a Webos D1 Mini with a similar setup.
I have so far a simple and standard connection like this:
I have checked all the wiring, pins, added an external power, 10uF capacitor, checked many threads and also the tutorial in this forum. Most of the examples are with MCU of 16Mhz but the Pro Mini is 8MHz.
I don't know what I'm missing or what else could I try.
Thank you
You are missing a lot of details that would be on an annotated schematic, why not post one. Show all connections, power, ground, power supplies etc. Links to technical information on the parts would help as well. Links to amazon are useless as they normally only contain sales data. I suspect you have a power problem.
Hi,
it seems that it was something related to intermitent bad connections of the jumpers or the protoboard, I'm still not sure of what was actually the problem. I had checked everything with the tester serveral times. It was driving me crazy.
I have replaced some of the dupont jumpers by direct bare cables and sorted it a bit and now it works fine.
Now it works without specifing the frequency. And in the debug output it still says " SPI Speedz = 10 Mhz". How can it be? I'm not very expert, but I understand that the MCU can't communicate with anything at a higher frequency than it's own (8 Mhz). Or is it posible? Maybe it just displays the initial defaults.
Actually it works very well. I set it at only 250Kbps and RF24_PA_MIN and it reach the other one through 3 walls in the house. Without the adapter and working at 3.3v
Regarding power comsuption, in the same conditions, about 20-30m and a couple of walls in a house, would a RFM69 consume less? as it has lower frequency I understand that it needs less power to communicate in the same conditions than the nRF24L01. Or maybe the difference is negligible?