Hi my ffriends,
I’m working on a wireless system called for me "Wireless Link Project", based on the nRF24L01 (non-Plus) transceiver.
I have two identical boards using an NXP MCF51MM256 MCU, and I’m trying to make them communicate in both directions using Auto-ACK.
Everything works fine when Auto-ACK is disabled, but when I enable it (EN_AA = 0x01, SETUP_RETR = 0x2F), I get this issue:
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The first packet is transmitted and acknowledged correctly.
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After that, no more ACKs are received.
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The receiver stays active and correctly switches between RX and TX modes, but the link seems to hang after the first exchange.
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STATUS and FIFO registers look normal, and CE/CSN timing is correct (verified with an oscilloscope).
Some extra details:
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Both devices use the same 5-byte address on Pipe 0.
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Channel = 8, 2 Mbps, 0 dBm output power.
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CRC = 1 byte.
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SPI clock = 3 MHz.
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Power rails are clean, with 100 nF + 100 µF decoupling capacitors.
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CE pulse timing follows the datasheet.
So basically, Auto-ACK works once after power-up and then stops.
I’ve tried flushing the FIFOs, clearing the STATUS register, and forcing RX mode again, but nothing helps.
Could you please:
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Confirm if there are any known timing or configuration differences for Auto-ACK on the nRF24L01 (non-Plus), and
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If possible, share a reference C library or example code that supports Auto-ACK and 8-byte payloads for bidirectional communication?
I’m using a custom SPI driver on the NXP microcontroller but can easily adapt any sample you provide.
Thanks a lot for your help and suport.
Best regards,
A. Molina
