2.11. Memory Blocks Error Correction Code Support
ECC allows you to detect and correct data errors at the output of the memory. ECC can perform single-error correction, double-adjacent-error correction, and triple-adjacent-error detection in a 32-bit word. However, ECC cannot detect four or more errors.
The M20K blocks have built-in support for ECC when in x32-wide simple dual-port mode:
- The M20K runs slower than non-ECC simple-dual port mode when ECC is engaged. However, you can enable optional ECC pipeline registers before the output decoder to achieve higher performance compared to non-pipeline ECC mode at the expense of one cycle of latency.
- The M20K ECC status is communicated with two ECC status flag signals—e (error) and ue (uncorrectable error). The status flags are part of the regular output from the memory block. When ECC is engaged, you cannot access two of the parity bits because the ECC status flag replaces them.