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SPI3 RXNE SLOW

Question asked by k.timothy on May 27, 2012
Latest reply on Feb 27, 2015 by stokic.srdjan
Hi,
I am using the STM32F107 micro, and tied an SD card into its SPI3 remmaped pins. As i saw in the datasheet the RXNE bit responce after the trasnmission is at worse 1 bit clock in duration. As you can see from the DSO timmings i measured this time response to be much worse , leading into a degradation of tranfer rate significantly. Also the returns from, while () and function call _spi_read_write(data) seems also to last too much for a 72MHz proccessor clock. So i am giving you the main code , and the settings of the peripheral clocks and SPI settings also. If you have any suggestions , please feel free to reply :) 

P.S. I used a simple loop in the main just send a byte after checking the TXE flag , then waited for RXNE flag to get high "1", then opened a debug I/O pin (PD2) then closed it "0" then read the RX register so the RXNE bit gets cleared, and then reloop.

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