tmedicci commented on issue #13855: URL: https://github.com/apache/nuttx/issues/13855#issuecomment-2447969612
@FelipeMdeO and @acassis. MOSI and MISO lines exchange data on every pulse clock. The "feature" @eren-terzioglu told you about can be better described as: "On every clock pulse, the slave device will receive data on MOSI line and transmit the content of the transmit buffer on MISO. After a byte is transmitted, its content will be overwritten with the byte just received in the receiver buffer". The consequence is: for the 1st transaction, if the transmitter buffer is not written, it would transmit its initial value (all zeros). For the 2nd transaction, if not written, it'd transmit the content received in the 1st transmission (that was copied to the transmit buffer during the 1st transmission). That being said, we can summarize it as: if not written between transmissions, the slave device will transmit the content received in the previous transmission. I don't know how other drivers behaves when the transmit buffer is not set between transmissions in the slave device: one could set to a pre-defined value between transmissions on upper-half driver, but the "problem" is about setting it between transmissions (which is done by the app). -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
