14.2 Features

The following are key features of the TCM module:

  • Fault injection allowed on DATA and ECC bits
    • User selection bits to specify which bit to fault on
    • Separate Fault injection for ITCM and DTCM
  • Error Logging with address, Host ID and syndrome for ITCM and DTCM
  • Single Error Correction and Double Error Detection (SECDED) module embedded in this for the ITCM/DTCM RAM which generates ECC, compares, detects the error bits, and corrects if it is a single bit error
    • On Reads capable of correcting single bit errors and detecting multiple bit errors
    • A total of 8 Bits (7(SEC)+1(DED)) ECC check bits associated with each 64-bit wide data word in the Instruction TCM (ITCM)
    • A total of 7 Bits (6(SEC)+1(DED)) ECC check bits associated with each 32-bit wide data word in the Data TCM, (DnTCM, n=0,1)
    • ECC enabled by default, but enable can be cleared by user, re-enabled by reset only
    • ECC enable can be overridden (disabled) in debug and test modes
    • Generates the corresponding ECC check bits for the data during a write operation and stores them in the associated ECC memory location. During a memory read the ECC bits are read along with the data to detect or correct any error.
  • The Data Tightly Coupled Memory (DTCM) is a dual 32-bit (2x32) interleaved interface allowing concurrent accesses (double word data width) to be optimized (for critical real-time data). The DTCM accesses are split so that lower words always access D0TCM and upper words always access D1TCM.
  • The Instruction Tightly Coupled Memory (ITCM) is a 64-bit interface (1x64) allowing a fetch of two 32-bit instructions (double word data width) in a single access, allowing for a benefit from a dual-issue capability (for real-time routines)
  • Pipelined ECC calculations to limit stalls on the TCM interface
  • Access speeds up to 300 MHz, with pipelined read/write
  • Hamming Code Based ECC Features
    • Up to 64-bit data path
    • Single Error Correction (up to 7-bit ECC)
    • Double Error Detection (+1-bit ECC)
    • Generates parity for write data
    • Calculates parity to correct read data
    • Generates syndrome of error bit
    • Correctable Error indication (read)
    • Uncorrectable Error indication (read)