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WRITE/READ COMMAND FOR NRF24L01 VIA SPI

Hi, i'm using the nrf24l01 with a zynq board to use it as radiocontrol; i'm trying to configure the nrf as receiver so that i'm able to send data from another nrf connected to an arduino. The first step i had to do, as i understood frome the datasheet, is being able to write and read register from nrf, so that i can configure nrf as receiver and also i can modify parameters for the communication (as bit rate, frequency,ecc). i tried to write the CF_REG with 00000011 (that are the setting for PRIM_RX and PWR_UP) using spi, and then reading the new content of the register. As i discovered i had to send the command and then the data i must overwrite, so i first sent 00100000 (that should be write register CF_REG), and then i sent 00000011, but it seems not to work. The first question i'd like to ask is if i have to send the 2 bytes with two different commands or if i can send a single command with a 2 bytes data (00100000-00000011 in this case).
The second question is if anyone already worked with zynq and is able to determine if i'm configuring properly the sdk. the code i wrote is below, thanks

void write(XSpiPs *myinstanceptr){
u8 * commandptr;
u16 command = 0b0010001000000011;
commandptr = &command;
u8 * dataptr;
u8 data = 0b00000011;
dataptr = &data;
XSpiPs_SetSlaveSelect(myinstanceptr,0);
(myinstanceptr)->IsBusy=0x00000000;
XSpiPs_Transfer(myinstanceptr,commandptr,NULL,2);
(myinstanceptr)->IsBusy=0x00000000;
//XSpiPs_Transfer(myinstanceptr,dataptr,NULL,1);
//(myinstanceptr)->IsBusy=0x00000000;
XSpiPs_SetSlaveSelect(myinstanceptr,0X0F);

}


u8 read(XSpiPs *myinstanceptr){
u8 * commandptr;
u8 command = 0x00;
commandptr = &command;
u8 * dataptr;
u8 data;
u8 *rcvptr2;
u8 rcv2;
rcvptr2 = &rcv2;
dataptr = &data;
u8 * rcvptr;
u8 rcv;
rcvptr = &rcv;
XSpiPs_SetSlaveSelect(myinstanceptr,0);
(myinstanceptr)->IsBusy=0x00000000;
XSpiPs_Transfer(myinstanceptr,commandptr,rcvptr2,1);
(myinstanceptr)->IsBusy=0x00000000;
XSpiPs_Transfer(myinstanceptr,dataptr,rcvptr,1);
(myinstanceptr)->IsBusy=0x00000000;
XSpiPs_SetSlaveSelect(myinstanceptr,0x0F);
return rcv;
}

int main(){
init_platform();
Xil_Out8(IRQ_BASE_ADDR,0x01);
XSpiPs *myinstanceptr;
XSpiPs_Config *myinstanceptr2;
XSpiPs instanceptr;
XSpiPs_Config instanceptr2;
myinstanceptr = &instanceptr;
myinstanceptr2 = &instanceptr2;
myinstanceptr2->InputClockHz = XPAR_PS7_SPI_0_SPI_CLK_FREQ_HZ;
XSpiPs_CfgInitialize(myinstanceptr,myinstanceptr2,XPAR_PS7_SPI_0_BASEADDR);
XSpiPs_SetOptions(myinstanceptr,XSPIPS_MASTER_OPTION);
//XSpiPs_SetClkPrescaler(myinstanceptr,XSPIPS_CLK_PRESCALE_256);
u8 result;
result = XSpiPs_IsManualChipSelect(myinstanceptr);
result = XSpiPs_IsDecodeSSelect(myinstanceptr);
result = XSpiPs_IsManualStart(myinstanceptr);
u8 *txbuf;
u8 *rxbuf;
u16 tx = 0b11001111;
u8 rx;
txbuf = &tx;
rxbuf = ℞
while(1){
write(myinstanceptr);
result = read(myinstanceptr);

}


return 0;

}



EDIT. the problem was due to the ZYNQ configuration that deasserted the csn between the end of a word and the following one, so that every byte was considered a new command for the nrf; this can easily be solved changing the function XSpiPs_SetOptions(myinstanceptr,XSPIPS_MASTER_OPTION); with the XSpiPs_SetOptions(myinstanceptr,XSPIPS_MASTER_OPTION | XSPIPS_CLK_PHASE_1_OPTION); (the clk phase option allows csn to keep asserted even during the transition of 2 word)

Parents Reply
  • If you're at a University then, surely, you should be able to get a teacher or supervisor - or even fellow student - to help you?

    That would be far easier and more efficient than trying to get remote debugging from complete strangers who have no idea what you're doing, or what equipment you have, no access to your hardware, etc, etc, ...

    if connected with two arduino they communicate properly

    a prime example: we have no way of knowing that!

    Anyhow, again, if you have comms working with an Arduino, then get logic analyser traces of that, and compare to what's happening in your system.

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