Hello shiven,
1)LPC802 doesn't support DMA.
2)Where said "做slave的话,SPI可以支持17.8Mhz," ? I don't think it can.
3) You can consider LPC845 or LPC824 :
https://www.nxp.com/products/processors-and-microcontrollers/arm-microcontrollers/general-purpose-mc...
BR
Alice
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