The ROM code unit (RCU) is a deeply embedded microcontroller that executes its BootROM code for device initializations after a POR or device level SRST reset. Then, the RCU looks for a boot header in the selected boot mode device. The boot sequence is described in the Platform Boot, Control, and Status TRM section. Boot success and errors are reported. After initial boot, the RCU provides tamper monitoring during system operation.
The RCU is based on a triple module redundancy (TMR) MicroBlaze™ processor. The MicroBlaze TMR and surrounding logic includes built-in ECC to provide an exceptionally high level of reliability in the RCU implementation.