Connect to RAM, ROM, and eFlash memory

Connect to RAM

You must use a RAM controller for each bank of RAM in the system. The AHB5 to internal RAM interface provides this functionality. To enable TrustZone monitoring of the transactions to the RAM, an AHB5 MPC must be placed before the RAM controller. Connect the AHB5 MPC to the bus matrix. Then connect the AHB5 to RAM interface to the AHB5 MPC.

Connect to ROM

You must use a ROM controller for each bank of ROM. The AHB5 to ROM interface provides this functionality. To monitor the transactions to the ROM, an AHB5 MPC must be placed before the ROM controller. Connect the AHB5 MPC to the bus matrix. Then connect the AHB5 to ROM interface to the AHB5 MPC.

Connect to eFlash

For non-volatile memory, use eFlash. The GFC-100 Flash Controller is an ideal controller for our secure IoT system. To monitor the transactions to the eFlash, place an AHB5 MPC between the bus matrix and the controller. If you need AHB5 exclusive access support, you must also consider adding an EAM.

The Flash controller and flash memory can operate in a different clock domain to the main domain. In that case, you must use an AHB5 to AHB5 sync-down bridge to synchronize the two AHB5 interfaces.

We recommend that you add a cache between the bus interconnect and eFlash controller. This addition helps to reduce the impact of high eFlash access latency and low bandwidth from the CPU. You can use the CG092 AHB Flash Cache. Position the Flash Cache after the AHB5 MPC and before the AHB5 to AHB5 sync-down bridge.

Both the GFC-100 Flash Controller and CG092 AHB Flash Cache have an APB4 interface in addition to an AHB5 interface. Connections to both the GFC-100 Flash Controller and CG092 AHB Flash Cache APB4 interfaces must be after an APB4 PPC.

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