Accessing RPD Register on nrf24LE1

Questions for programming 8051 microcontrollers in C or assembly using SDCC

Accessing RPD Register on nrf24LE1

Postby lorenberg » Mon Nov 25, 2013 10:30 am

Hi everyone,

I'm quite new to embedded systems programming, and I started a project where I need to use the nrf24LE1 chip from Nordic Semiconductor.

I need to access the RPD bit in order to evaluate the noise on a given channel, but I was not able to find a way to access this register.

I read on the datasheet that the RPD is a bit in the register number 9, but I was unable to find any reference to RPD register inside the

header files given with nordic SDK.

I think it should be quite easy, but it's now a couple of days that I'm stuck on this stupid issue.

Thanks in advance for your help!
lorenberg
 
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Re: Accessing RPD Register on nrf24LE1

Postby brennen » Mon Nov 25, 2013 1:02 pm

What assembler/compiler are you using?
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Re: Accessing RPD Register on nrf24LE1

Postby lorenberg » Mon Nov 25, 2013 3:52 pm

I'm using Keil C51.

But actually I realized that I can access that register using the old name "CD", i.e. the register that was used on nrf24l01+.

I was successful in accessing information using this name instead of RPD....I don't know if it was an error on the datasheet or on the Keil header file I got
with Nordic SDK....but surely it was a bit strange. Nonetheless, the information I got are correct, as well as the address to which CD bit is referring in my headers.

Only problem is that I actually noticed that the RPD (or CD, whatever it is) bit, is set to 1 only when the transmitter is sending something using exactly the same
datarate and same channel of the receiver.

I need to realize a kind of spectrum analyzer, to detect activity on a given channel, but it seems that it's not possible to rely on the CD bit for this purpose.

Do you have any other possible idea?
lorenberg
 
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Re: Accessing RPD Register on nrf24LE1

Postby brennen » Mon Nov 25, 2013 4:22 pm

There was a discussion a while back about the RPD bit. See it here: viewtopic.php?f=4&t=3617&p=4144&hilit=rpd#p4144.
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Re: Accessing RPD Register on nrf24LE1

Postby lorenberg » Mon Nov 25, 2013 6:33 pm

Thanks for the support, now I fixed the issue and was able to access the register :).

By the way....do you know if there is any means to receive actual bytes from a given channels? I mean, since I need to create a kind of packet sniffer, I realized that the RX interrupt is triggered only when a VALID packet
is detected by the RF transceiver on the air. Otherwise, no RX is signaled.

Do you know if there is a way I can just attemp a reception of every kind of energy I detect on the channel I'm currently analyzing? (I know I will probably receive just a sequence of bytes, but it does not matter for now).

Thanks again, and congratulations for the outstanding job you've done so far with this forum and your website!
lorenberg
 
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Re: Accessing RPD Register on nrf24LE1

Postby brennen » Mon Nov 25, 2013 7:01 pm

Unfortunately, using the L01 and L01+ radios as packet sniffers isn't very viable, unless you know the parameters of the radio you're sniffing. You have to have virtually every parameter right in order for the L01(+) radios to register that they received a packet, so you'd have to know most of the register settings up front.

And thanks for your kind words!
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