nrf24l01+ reset register values

[paolo lucantonio]

hi everyone, i'm trying to read the register values in nrf24l01+ since i need to use nrf as radiocontroller. Due to the fact i couln't write any bit on registers i tried to check if my functions were the main problem, so i tried the read function. I noticed that some registers didn't have the reset value described in the register map section of the datasheet, while others have (for example configuration register has 00001000 that is the reset sequence shown in the datasheet). Does anyone have an idea of why there aren't the reset value in the register? (i checked the 4 spi signal that i send to the nrf with a logic analyser and according to the timing information of the spi section of the datahseet they should be correct).

[Kenneth]

What registers differ? Have you checked with a logic analyzer that the SPI commands (read and write) is as shown in the datasheet of the nRF24L01+?

[paolo lucantonio]

yes i checked and they should be correct as i can see; almost every register has a strange value printed in the logic analyzer like the freqeuncy register that has 00000000 as result, i hope not to be so unlucky that i wrote a wrong function that casually returns me the correct value of config register and a few more.

[Kenneth]

Can you share a plot of csn, sck, mosi and miso when for instance reading the STATUS register.

The plot need to be detailed enough to see each of the 16 clock cycles for the command(1byte) + data(1byte). Should be similar to figure 26 in datasheet (but that figure show 1 more byte than you need to read STATUS register):

https://infocenter.nordicsemi.com/pdf/nRF24L01P_PS_v1.0.pdf?cp=8_4_0_0

[paolo lucantonio]

the status register is read correctly since is sent as 00001110 as the datasheet says, the problem is that i can neither write 1 the pwr_up to make the nrf to go on stand by mode nor reading correctly other registeres, for example today i tried several times to read the 0x01 register and instead of 00111111 there was written 00000000; tomorrow as i'll go in lab i try to send a picture of the logic analyzer screen; if can be of any help i can also share code written in sdk

[paolo lucantonio]

i solved the problem, it seems that ZYNQ injected too much current in the clock pin, so inserting a 1Mohm resistor in series between zynq pin and nrf one solved the problem, now i can properly write/read (the arduino provides a 12Mohm resistance in the clock pin while the zynq 300kohm)