5.9.7 Parameter Overlay Module (POM) Considerations
The Parameter Overlay Module (POM) is implemented as part of the L2FMC module. It is used to redirect flash memory accesses to external memory interfaces or internal SRAM. The POM has an OCP master port to redirect accesses. The POM MMRs are located in a separate block and read/writes will happen through the Debug APB port on the L2FMC. The POM master port is capable of read accesses only. Inside the CPU Subsystem SCR, the POM master port is connected to both the L2RAMW and EMIF slaves. The primary roles of the POM are:
- The POM snoops the access on the two flash slave ports to determine if access should be remapped or not. It supports 32 regions among the two slave ports.
- If access is to be remapped, then the POM kills the access to the flash bank, and instead redirects the access through its own master.
- Upon obtaining response, the POM populates the response FIFO of the respective port so that the response is delivered back to the original requester.
- The access is unaffected if the request is not mapped to any region, or if the POM is disabled.
- The POM does not add any latency to the flash access when it is turned off.
- The POM does not add any latency to the remapped access (except the latency, if any, associated with the getting the response from the an alternate slave)