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nucleo-h743zi transfer data from SD card to serial line at 20Mhz

Question asked by Luc Tronco on Feb 8, 2018
Latest reply on Feb 11, 2018 by Luc Tronco

Hi,

 

for a new project I have to transfer data from a SD card to a serial line SDI (1 GPIO line). The data has to be synchronized with a 20 Mhz clock CK. 

At certain times , controlled by an external encoder signal, a data block of 434 bits has to be transferred synchronous with the 20Mhz clock. The time between 2 data blocks is minimum 70uS.

Till now I have configured timers to make a 20Mhz clock, to read the encoder clock and to generate the start trigger with the 20Mhz clock for the 434 bits transfer.

 

In total I need 2 SDI lines. Each line needs different data (same format) and is shifted in time. (the second SDI line starts a few mS later compared to the first SDI line).

 

Now I'm struggling with how I have to transfer the data from the SD card to the serial line.

The format of the data inside the file on the SD card I can manipulate to the format best for this transfer.

 

Does someone has an idea how I can make this (DMA) data transfer from SD card to serial line?

 

Thanks,

 

Luc

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