Intel® Arria® 10 Hard Processor System Technical Reference Manual

ID 683711
Date 8/28/2023
Public
Document Table of Contents

20.5.6.4. Receive FIFO Buffer Overflow

During SPI serial transfers, receive FIFO buffer requests are made to the DMA whenever the number of entries in the receive FIFO buffer is at or above the DMA Receive Data Level Register, that is DMARDLR + 1.This is known as the watermark level. The DMA responds by fetching a burst of data from the receive FIFO buffer. †

Data should be fetched by the DMA often enough for the receive FIFO buffer to accept serial transfers continuously, that is, when the FIFO buffer begins to fill, another DMA transfer is requested. Otherwise the FIFO buffer fills with data (overflow). To prevent this condition, the user must set the watermark level correctly. †