Intel® Arria® 10 Hard Processor System Technical Reference Manual

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

20.4.8.2. Data Register Access

The data register (DR) within the SPI controller is 16 bits wide in order to remain consistent with the maximum serial transfer size (data frame). A write operation to DR moves data from the slave write data bus into the transmit FIFO buffer. An read operation from DR moves data from the receive FIFO buffer onto the slave readback data bus. †

Note: The DR register in the SPI controller occupies sixty‑four 32‑bit locations of the memory map to facilitate burst transfers. There are no burst transactions on the system bus itself, but SPI supports bursts on the system interconnect. Writing to any of these address locations has the same effect as pushing the data from the slave write data bus into the transmit FIFO buffer. Reading from any of these locations has the same effect as popping data from the receive FIFO buffer onto the slave readback data bus. The FIFO buffers on the SPI controller are not addressable.