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Hello,

I'm working with some nRF24L01+ modules but I haven't succeeded in sending information.

So far I haven't been able to transmit any information:

- TX_DS is always 0 (in STATUS register)
- The TX FIFO is full (in FIFO_STATUS register TX_FULL = 1)
- The IRQ signal is never cleared (since TX_DS is always 0)

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In order to send information:

- I send the payload (5 bytes) using the command W_TX_PAYLOAD
- I set PRIM_RX = 0 and PWR_UP = 1 in the CONFIG register (I turn on the transceiver and I set PTX)
- I wait ~2 ms
- I set CE = 1
- I wait 100 us
- I clear CE = 0

Nothing happens

- IRQ signal = 1
- TX_DS = 0;
- The information is still in the FIFO TX

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After setting PWR_UP = 1:

- I see how the Crystal starts oscillating
- I see a 1.8 V signal in VDD_PA pin

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Configuration of the module:

Code: Select all


Pin Configuration

MOSI = SCK = CSN = 1
CE = 0

Registers Configuration

Wait 100 ms to let the module turn on

CONFIG register = 0x00 (IRQ enabled, CRC Disabled, Power down, TX mode)

EN_AA register = 0x00 (Disable auto acknowledgement)

EN_RXADDR register = 0x01 (Enable data pipe 0)

SETUP_AW register = 0x03 (RX/TX Address = 5 bytes)

SETUP_RETR register = 0x00 (Re - Transmit Disabled)

RF_CH register = 76 (RF Channel selection)

RF_SETUP register = 0x00 (Disable continuous carrier TX, 1 Mbps data rate, Power = -18 dBm)

STATUS register = 0b01110000 (Reset STATUS register)

RX_ADDR_P0 register = 0xB6B5B4B305 (RX0 Address = 0xB6B5B4B305)

TX_ADDR register = 0xB6B5B4B305 (TX Address = 0xB6B5B4B305)

RX_PW_P0 register = 5 (Payload size = 5)

Flush TX FIFO (Command FLUSH_TX)

Flush RX FIFO (Command FLUSH_RX)

Power Up the module


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I'm able to interact with the module via Software and Hardware SPI; Is my assumption since the module is responsive to the commands I send and the values that I read are correct

The 3V3 power supply line is not perfect but is fairly clean.

In addition to the suggested capacitors, I added a 100 uF capacitor between 3V3 and Ground to filter the signal and to give the extra current that the nRF24L01+ may need, I have also tried with 47 uF and 10 uF

I also tried powering up my design using an external DC Power Supply

I send payloads with different information (until the TX FIFO is full)

I'm not using CRC, Acknowledges, etc. I thought it would be nice to keep it simple at the start.

I don't think the module is getting reset at any point, since the values in the configuration registers are unchanged. (I have checked this at different points)

Is there perhaps a specific order in which the module needs to be initialized? Or Timings?

Is there any way to confirm in which state the Radio control state diagram is at? (Figure 4 of the datasheet)

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I greatly appreciate your help, if you have concerns about Code Implementation, Schematics, Oscilloscope lectures, etc. Please let me know and I will gladly share the details.

Make sure that CONFIG.PRIM_RX = 0 and CONFIG.PWR_UP = 1 on your setup. If those are set correctly, and you're still seeing STATUS.TX_FULL go to 1 when you upload packets via the W_TX_PAYLOAD command, then the only problems left are that your CE pin is not being toggled correctly, or else there is a bad connection between the CE pin on the nRF24L01 and the pin you're using to control CE on your microcontroller.