nrf24l01 playload datarate

RE: nrf24l01 playload datarate

ovrebekk — Wed, 13 Sep 2017 07:43:26 GMT

That is good news :)
The best of luck with your project.

RE: nrf24l01 playload datarate

pengyong — Wed, 13 Sep 2017 07:40:11 GMT

It is ok now. The through put is muck higher than before. Thanks a lot.

RE: nrf24l01 playload datarate

ovrebekk — Wed, 13 Sep 2017 06:47:50 GMT

The procedure is quite straight forward:

Set CE high
Upload a packet to the TX FIFO as quickly as possible
If time passed is less than 4ms, repeat from 2)
Set CE low
Wait for the next TX interrupt to occur
Repeat from 1)

Best regards

RE: nrf24l01 playload datarate

pengyong — Tue, 05 Sep 2017 06:53:18 GMT

I have a testing as below:

define MAX_TX 0x10 define TX_OK 0x20 define RX_OK 0x40

u8 NRF24L01_TxPacketContinous(u8 txbuf[8][32],u8 packetNum) { u8 sta,i; u8 outPut[20];

//NRF24L01_CE=0;
//NRF24L01_CE=1; //always in 1
for(i = 0 ; i < packetNum; i ++){
	while(1){
        sta=NRF24L01_Read_Reg(STATUS);  //get status	
        if(!(sta&0x1)) //TX FIFO not full
        {
		    NRF24L01_Write_Buf(WR_TX_PLOAD,&txbuf[i][0],TX_PLOAD_WIDTH);//write data to FIFO
		    break;
        }
	}
while(NRF24L01_IRQ!=0);
}
while(1){
  sta=NRF24L01_Read_Reg(STATUS);  //get status	 
  if(sta&0x20) //send comlete
  {
    break;
  }
}
NRF24L01_Write_Reg(WRITE_REG+STATUS,sta);
if(sta&MAX_TX)
{
	NRF24L01_Write_Reg(FLUSH_TX,0xff);
	llprintf("tran failed\n");
	return MAX_TX; 
}
if(sta&TX_OK)//SEND COMPLETED
{
	return TX_OK;
}

return 0xff;//OTHER ERROR

} But it not well.Looks some packet lost or can not be received correctly. Thanks. Yong

RE: nrf24l01 playload datarate

pengyong — Mon, 04 Sep 2017 08:52:08 GMT

Hi Torbjørn,

It is great. I will try the though put 1.5Mbps.It is very important for my application. Could u give me some advice for the configuration to enabled over multiple packets and to to upload the next packet to the FIFO? Looks there is no more detail specification on datasheet document.It will be very helpful to me if there is a demo for the configuration. Thanks.

Yong

RE: nrf24l01 playload datarate

ovrebekk — Mon, 04 Sep 2017 08:42:25 GMT

Hi Yong

If you take advantage of the possibility to keep CE enabled over multiple packets (up to a maximum time of 4ms) you can reach 1.5Mbps or more in legacy Shockburst mode, yes.

For this to work you have to upload the next packet to the FIFO while the current packet is being transmitted.

Still, it is important to disable the TX temporarily after 4ms, otherwise the carrier frequency might drift out of spec and the packets will be lost.

Best regards

RE: nrf24l01 playload datarate

pengyong — Mon, 04 Sep 2017 01:58:40 GMT

Hi Torbjørn, I agree with u. Another question, what is the max through put for the NACK Mode, can it reach 1.5mbps? Thanks. Yong

RE: nrf24l01 playload datarate

ovrebekk — Thu, 31 Aug 2017 14:14:12 GMT

Hi Yong

You can't really guarantee less than 2% packet loss at 60m. If you have line of sight, a good antenna and little interference then you might achieve it, but in other situations I am sure you will have much higher packet loss (like if you have walls in between, if there is a lot of 2.4GHz interference in the area, if the antenna is not properly tuned and so forth).

Best regards

RE: nrf24l01 playload datarate

pengyong — Wed, 30 Aug 2017 07:21:45 GMT

Hi Torbjørn, In my testing SPI clock speed is 9MHz. Looks like SPI is quick enough so that 400-500us sleep need after send a packet with 32 Bytes by SPI. Is possiable with about 500kbps thoughput and 60M distance and no more than 2% pakcet error or lost? Thanks. Yong

RE: nrf24l01 playload datarate

ovrebekk — Tue, 29 Aug 2017 14:28:15 GMT

Hi Yong

What is the SPI clock speed?

Have you looked at the SPI communication with the scope to check how much of the time it is active?

Best regards

RE: nrf24l01 playload datarate

pengyong — Mon, 28 Aug 2017 07:56:30 GMT

Hi,

Thanks for you feedback. 1)The auto ACK NOT enable.I used maximum payload size (32). 2)In the testing, when a packer(32bytes) sent, 300-400us will wait for sending the next.It will take more than 500us to send a single packet.If this were is no wait, the receiver can not get correct packets. 3)The radio capability for the throughput is 2Mbps. In my testing, the sending throughput is much lower the capability .

I also have a test for the EN_AA enabled, Looks the throughput is no more than 500kbps.

In my testing, looks the receiver can not get the data immediately if keep a low error packet rate. The configuration as below: FOR TX: NRF24L01_CE=0;
NRF24L01_Write_Buf(WRITE_REG+TX_ADDR,(u8*)TX_ADDRESS,TX_ADR_WIDTH); NRF24L01_Write_Buf(WRITE_REG+RX_ADDR_P0,(u8*)RX_ADDRESS,RX_ADR_WIDTH);

NRF24L01_Write_Reg(WRITE_REG+EN_AA,0x00); 
NRF24L01_Write_Reg(WRITE_REG+EN_RXADDR,0x01); 
//NRF24L01_Write_Reg(WRITE_REG+SETUP_RETR,0x1a);
NRF24L01_Write_Reg(WRITE_REG+SETUP_RETR,0x0);

NRF24L01_Write_Reg(WRITE_REG+RF_CH,120);  
//NRF24L01_Write_Reg(WRITE_REG+RF_SETUP,0x0f);
NRF24L01_Write_Reg(WRITE_REG+RF_SETUP,0x0f); 
//NRF24L01_Write_Reg(WRITE_REG+CONFIG,0x0e); 
NRF24L01_Write_Reg(WRITE_REG+CONFIG,0x02); 
NRF24L01_CE=1;

FOR RX: NRF24L01_CE=0;
NRF24L01_Write_Buf(WRITE_REG+RX_ADDR_P0,(u8*)RX_ADDRESS,RX_ADR_WIDTH);

NRF24L01_Write_Reg(WRITE_REG+EN_AA,0x00);    
NRF24L01_Write_Reg(WRITE_REG+EN_RXADDR,0x01);
//NRF24L01_Write_Reg(WRITE_REG+EN_RXADDR,0x00);
NRF24L01_Write_Reg(WRITE_REG+RF_CH,120);	  	  
NRF24L01_Write_Reg(WRITE_REG+RX_PW_P0,RX_PLOAD_WIDTH);
NRF24L01_Write_Reg(WRITE_REG+RF_SETUP,0x0f);
//NRF24L01_Write_Reg(WRITE_REG+CONFIG, 0x0f);
NRF24L01_Write_Reg(WRITE_REG+CONFIG, 0x03);
NRF24L01_CE = 1;

Is there any unreasonable configuration?

Thanks Yong

RE: nrf24l01 playload datarate

ovrebekk — Thu, 24 Aug 2017 13:35:17 GMT

If you use the ACK mechanism (EN_AA enabled) then the data rate is usually < 800kbps, but 450kbps sounds a bit low.

A couple of pointers and follow up questions:

Are you using auto ACK or not, and are you using the maximum payload size (32) ?
Have you checked how long it takes to upload a single packet to the nRF24L01+ ?
If this command is running slowly then it might slow down overall data rate.
Are you taking advantage of the capability of the radio to upload more packets while the previous packet is being transmitted over the air?

As soon as the first packet is uploaded you can start uploading the second.

Best regards
Torbjørn Øvrebekk
Application Engineer
Nordic Semiconductor