nrf2401 problem

Wireless & IoT
1

I have 2 nrf2401 MiRF V01 modules. One is connected to a PIC18F252 and the other to

a olimx LPC-H2214 board.

MiRF PIC 2214

DATA A0 P0.13

CLK A1 P0.12

DD A2 P0.11

CS A3 P0.10

CE A5 P0.09

I used a logic analyized to verify the data transfers during setup and transmission but

there is no indication of radio transmission. The only observed abnormal condition is

the data pin on the PIC module has a high of 2.0V while the data pin on the 2214

goes to 3.2V.

Disabling the CRC causes the DATA and DD pins to fire with random indicates the chips

are working and that at least some on the config is being set.

Help!!!

Reagrds,

George

2

As an update to my prior post, setting the output power to -5 dBm, as per sparkfun

sample, make things work at close range (2 feet). My intended operational distance

is ~50ft (17m).

The reliability of transmitting 9 byte messages is very poor. It is better at 250K than

1M.

George

3

it is better at 250k than at 1M.

You have to consider a few things.

Set the Rf power to the highest possible, drains a little more current, but better transmission.

Consider that the chip does not have auto retransmission (the L01 does, SparkFun get these! =)

Therefore if you want this to be reliable, you have to write the reliability yourself. I did a somewhat reliability. I did retransmission up to 5 times if unsuccessful. It worked 99% of the time.

Also try this. Keep sending packets at a constant rate, you will see that the transmission isn’t that bad.

I get up to 50kbps of actual payload.

If you need somehting better, go with bluetooth or something - auto retransmit build in…eveyrhting build in.

4

Can you provide some deatils of the retransmissin scheme? Does the destination

device ACK and the retries are due to lack of ACK?

Also, what is the meaning for the rf power setting? The only one I seem to get

any connection on is -5.

Thanks,

George

5

Like I said, the nRF2401 DOES NOT have retransmission. Therefore if the packet is lost, nobody cares. If you do, then you have to write a communication scheme for it. Look up TCP on the internet and you’ll see how acknowledgments are done.

I’m running at 0dB and it works fine. Probably better because its giving out more power. Bits 8 and 9 should be 11 for this config.