nrf24l01+ data loss

[Leonardo]

Hello,

I have problem with two nRF24l01+

First is connected with a mcu to a sensor. Second is connected with a mcu to a pc throught usb.

I want to get data from sensor into PC but sometimes (not always) some data is missing.

I'have taken waveforms with a logic state analyzer from nRF connected to PC.

Initially there is an handshake (write and read some data) then first nRF send a burst of data, in waveform is shown data receive (320x240x2 bytes + overhead of Enhanced Shockburst) but at +4s communication get interrupted for 0.2s

i60.tinypic.com/2nj8vgz.png

here are details of waveform before interruption

i60.tinypic.com/2enbzut.png

and after interruption of 0.2s

i60.tinypic.com/rmij9z.png

Problem is that I receive only 320x234x2 bytes and 12 bytes are missing..

Thank you Leonardo

EDIT

Here is a good and a bad transmission

It seem that nrf that RX stall at some point and then resume but last bytes are lost

[Asbjørn]

How are you configuring the nRF24L01+? Are you keeping the transmitter in TX_EN for a long time? Do you actually lose radio packets (check ARD and ARC) on the PTX side?

[Leonardo]

I will check ARD and ARC registers on PTX side.

Datasheet say that

It is important never to keep the nRF24L01+ in TX mode for more than 4ms at a time. If the Enhanced ShockBurst features are enabled, nRF24L01+ is never in TX mode longer than 4ms

But with Shockburst should be no problem keeping TX active for long time... or not?

Problem is after 20-30 seconds of device running

Thank you

[Asbjørn]

The same 4 ms rule applies for Shockburst as well. Please reset the PLL on the transmitter by toggling TX_EN at least once every 4th ms.

[Leonardo]

I have some retransmission occasionally.

There isn't TX_EN register, do you mean PRIM_RX in CONFIG register?

Thank you

PS: Shockburst should not change automatically to RX to receive ACK packets? Why I have to switch to Standby?

[Asbjørn]

I'm sorry, the TX_EN name is my mixup, I was referring to the CR pin. You can't hold the chip in TX mode with CE high for longer than 4 ms at the time.