2025-05-19 11:45 PM - last edited on 2026-06-01 3:32 AM by Andrew Neil
Hi,
I am working on implementing SPI communication over Ethernet using the LAN9250. I want to develop APIs on the STM32 to interface with the LAN9250
I am trying to transmit data using the TXDATAFIFO register and read it using the RXDATAFIFO register, which is located at address 0x00.
In the main function, I pass the RXDATAFIFO address (0x00), but I keep getting 0xFF as the output. How can I resolve this issue?
2025-05-20 3:23 AM
Welcome to the forum.
Please see How to write your question to maximize your chances to find a solution for best results; in particular, How to insert source code - not as screenshots.
As noted in your previous thread, the LAN9250 is a Microchip product - nothing to do with ST - so you need to go to Microchip for support with it:
https://www.microchip.com/en-us/support
@Ranjitha wrote:In the main function, I pass the RXDATAFIFO address (0x00), but I keep getting 0xFF as the output. How can I resolve this issue?
The first thing to do would be to use an Oscilloscope on the SPI lines to ensure that the signals are good.
Then use an analyser to capture the comms between your STM32 and the LAN9250, and verify that against the LAN9250 specifications.
https://www.microchip.com/en-us/product/lan9250
https://www.microchip.com/en-us/product/lan9250#Tools%20And%20Software
https://ww1.microchip.com/downloads/en/DeviceDoc/LAN9250-Quick-Start-Guide-50002993.pdf
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