STM32F411 doesn't receive data

[iGerchak]

Hi All,
My hardware:

• NRF24L01+PA+LNA
• Arduino Nano
• STM32F411CE (black pill)

I tried to communicate between Arduino Nano and STM32F411CE (black pill) and had an issue with the communication.
In general, Arduino should be TX and STM32 RX.
When I try to send data to the STM32, always get a fail and STM32 doesn't receive any data.
After that, I connected another Arduino Nano instead of STM32 with the same code to check if NRF24L01 was working well, and as a result, it worked well.
So, after debugging for a few days, I found that if switch STM32 to TX and Arduino to RX, Arduino gets data, but on the STM32 payload is not available.

I tried different configs, pin connections, examples from the lib, power supplier, SPI speed, etc. but can't fix it.

Here are the details:
STM32:

================ SPI Configuration ================
CSN Pin                 = 196
CE Pin                  = 200
SPI Frequency           = 10 Mhz
================ NRF Configuration ================
Channel                 = 96 (~ 2496 MHz)
RF Data Rate            = 1 MBPS
RF Power Amplifier      = PA_MAX
RF Low Noise Amplifier  = Enabled
CRC Length              = 16 bits
Address Length          = 5 bytes
Static Payload Length   = 32 bytes
Auto Retry Delay        = 250 microseconds
Auto Retry Attempts     = 15 maximum
Packets lost on
    current channel     = 0
Retry attempts made for
    last transmission   = 0
Multicast               = Disabled
Custom ACK Payload      = Enabled
Dynamic Payloads        = Enabled
Auto Acknowledgment     = Enabled
Primary Mode            = RX
TX address              = 0xE7E7E7E7E7
Pipe 0 (closed) bound   = 0xE7E7E7E7E7
Pipe 1 ( open ) bound   = 0x65646F4E31
Pipe 2 (closed) bound   = 0xC3
Pipe 3 (closed) bound   = 0xC4
Pipe 4 (closed) bound   = 0xC5
Pipe 5 (closed) bound   = 0xC6

Arduino:

SPI Frequency           = 10 Mhz
Channel                 = 96 (~ 2496 MHz)
Model                   = nRF24L01+
RF Data Rate            = 1 MBPS
RF Power Amplifier      = PA_MAX
RF Low Noise Amplifier  = Enabled
CRC Length              = 16 bits
Address Length          = 5 bytes
Static Payload Length   = 32 bytes
Auto Retry Delay        = 250 microseconds
Auto Retry Attempts     = 15 maximum
Packets lost on
    current channel     = 0
Retry attempts made for
    last transmission   = 15
Multicast               = Disabled
Custom ACK Payload      = Enabled
Dynamic Payloads        = Enabled
Auto Acknowledgment     = Enabled
Primary Mode            = TX
TX address              = 0x65646f4e31
pipe 0 ( open ) bound   = 0x65646f4e31
pipe 1 ( open ) bound   = 0xc2c2c2c2c2
pipe 2 (closed) bound   = 0xc3
pipe 3 (closed) bound   = 0xc4
pipe 4 (closed) bound   = 0xc5
pipe 5 (closed) bound   = 0xc6

Code of STM32:

#include <Arduino.h>
#include <Wire.h>
#include <SPI.h>
#include "nRF24L01.h"
#include "RF24.h"

//------------------ Radio ----------------------------
#define MOSI PA7
#define MISO PA6
#define SCK PA5
RF24 radio(PB0, PA4); // CE, CSN
byte address[][6] = { "1Node", "2Node", "3Node", "4Node", "5Node", "6Node" };
//------------------ END Radio ------------------------

void setup() {
    SPI.begin();
    SPI.setMOSI(MOSI);
    SPI.setMISO(MISO);
    SPI.setSCLK(SCK);
    Serial.begin(115200);
    Wire.begin();
    while (!Serial);

    if (!radio.begin()) {
        Serial.println(F("radio hardware is not responding!!"));
        while (1) {}  // hold in infinite loop
    }

    radio.begin();
    radio.setAutoAck(1);
    radio.setRetries(0, 15);
    radio.enableAckPayload();
    radio.setPayloadSize(32);
    radio.openReadingPipe(1, address[0]);
    radio.setChannel(0x60);
    radio.setPALevel(RF24_PA_MAX);
    radio.setDataRate(RF24_1MBPS);
    radio.powerUp();
    radio.startListening();
    char buffer[870] = { '\0' };
    uint16_t used_chars = radio.sprintfPrettyDetails(buffer);
    Serial.println(buffer);
    Serial.print(F("strlen = "));
    Serial.println(used_chars + 1); // +1 for c-strings' null terminating byte
}

void radioCommunication() {
    byte pipeNo, gotByte;

    while (radio.available(&pipeNo)) {
        radio.read(&gotByte, 1);
        radio.writeAckPayload(pipeNo, &gotByte, 1);
        Serial.print("Recieved: ");
        Serial.println(gotByte);
    }
}

void loop() {
    radioCommunication();
}

[2bndy5]

    radio.begin();
    radio.setAutoAck(1);
    radio.setRetries(0, 15);
    radio.enableAckPayload();
    radio.setPayloadSize(32);

A few problems here:

1. radio.begin() doesn't need to be called twice.
2. Care should be taken when setting the auto-retry delay (0 means 250 microseconds). The delay specified here is the amount of time that the radio waits for auto-ACK packets. The datasheet recommends using 500 microseconds (1 means 250 + (250 * 1) = 500 ) or more when using ACK payloads (of at least 5 bytes).
3. Using ACK payloads requires enabling the dynamic payloads feature. Internally this is done for pipes 0 and 1 when enableAckPayload() is called, but just beware other pipes won't be usable unless the enableDynamicPayloads() is invoked.
4. Building off of point 3, setPayloadSize() (for statically sized payloads) is useless when using dynamic payloads feature.

I tried different configs, pin connections, examples from the lib, power supplier, SPI speed, etc. but can't fix it.

I highly suspect this is a power supply problem due to the use of PA/LNA modules. If you tried the library examples (specifically the ACK payloads example) and it still failed on your STM32, then I think this is a hardware problem (not a software problem). Did you read through our COMMON_ISSUES.md?

[iGerchak]

@2bndy5 Thank you for the quick answer.
Some bugs in the code can be as I modified it a lot of times during debugging.

Yes, I tried the ACK payloads example, here are the results:

As you can see in the screenshot, the payload on the STM32 isn't available.
And after switching a role, Arduino can't send data.

Did you read through our COMMON_ISSUES.md?

Yes, a few times)
But I haven't tried to use a capacitor before, because I use a power adapter like this:

So, will try to add a capacitor.

[2bndy5]

Just make sure the adapter board's VCC pin is getting at least a stable 150 mA (at 5 V of course).

[iGerchak]

I connected an additional power supply to the STM32 board, and now it works!!!!
So, power from USB isn't enough for NRF24L01+PA+LNA.
@2bndy5 thank you so much!