Arria V Hard Processor System Technical Reference Manual

ID 683011
Date 12/02/2022
Public
Document Table of Contents

19.5.2. Enabling SPRAM ECCs

To avoid false ECC errors, you must initialize the ECC bits in the SPRAM before using ECCs. To initialize the ECC bits, software writes data to all locations in the SPRAM.

The L3 interconnect has access to the SPRAM and is accessible through the USB OTG L3 slave interface. Software accesses the SPRAM through the directfifo memory space, in the USB OTG controller address space.

The SPRAM contains 8192 (32 KB) locations. The L3 slave provides 32‑bit access to the SPRAM. Physically, the SPRAM is implemented as a 35‑bit memory, with the highest three bits reserved for the USB OTG controller’s internal use. When a write is performed to the SPRAM through the L3 slave interface, bits 32 through 34 of the internal data bus are tied to 1, to enable the ECC bits to be initialized.

Note: Software cannot access the SPRAM beyond the 32‑KB range. Out‑of‑range read transactions return indeterminate data. Out‑of‑range write transactions are ignored.