16.12.1 Principle of Operation

The DSU provides memory services, such as CRC32 or MBIST that require almost the same interface. Therefore, the Address, Length and Data registers (ADDR, LENGTH, DATA) are shared. These shared registers must be configured first; then a command can be issued by writing the CTRL control register. When a command is ongoing, other commands are discarded until the current operation is completed. STATUSA.FAIL is set when commands are discarded. The recommended procedure to issue a command is given below:

  1. Clear STATUSA.DONE (by writing a 1 into STATUSA.DONE).
  2. Issue a command (by writing a valid command into CTRL.CMD).
  3. Wait until STATUSA.DONE is set.