SPI MISO Output with Arduino Uno and NRF24L01P ..... Help!!!!!

Using Arduino Networking, Protocols, and Devices
#1

Hi

I have connected my UNO with nRF24l01P without any logic level shifter since, NRF inputs are 5V tolerant. I have powered up nRF with 3.3V.

However, my MISO output (as seen in oscilloscope) swings between 0 to 3.3V and the rising and falling edges are quite slanted. Is this how its supposed to be ?

Shouldn't MISO output swing between 0-5V. Any help would be highly appreciated.

Also, I am using maniacbug's NRF24L01 library without any modification

Regards

#2

Have a look at this Simple nRF24L01+ Tutorial. I have included connection diagrams and the examples do work - but use the newer TMRh20 version of the RF24 library which solves some problems from the earlier ManiacBug version.

...R

#3

Thanks.

I have the proper connection. I will try out the new TMRh20 version of the RF24 library and report the outcome.

Just to let you know I can send and receive packets with the previous code, just that the number packet drops is quite high. I thought it has to do with the MISO not giving proper output.

#4

The MISO signal, if its connected correctly to the nRF, should swing between 0 and 5V. If its not, then remove the nRF and measure it again to make sure it is. If its 5V at the connector but 3.3V at the input to the nRF, look for circuitry that might divide down the voltage to the nRF. The fact that you see some distortion on the waveform also might mean that the nRF is potentially damaged.

#5

MISO = Master In, Slave Out. It may only be 0-3.3V coming from the RF module. It is not an Arduino output.

#6

Oops, mixed up the MOSI and MISO. You're correct, CrossRoads.

#7