DocID018909 Rev 11 59/1731
RM0090 Memory and bus architecture
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2 Memory and bus architecture
2.1 System architecture
In STM32F405xx/07xx and STM32F415xx/17xx, the main system consists of 32-bit
multilayer AHB bus matrix that interconnects:
The main system consists of 32-bit multilayer AHB bus matrix that interconnects:
• Eight masters:
–Cortex
®
-M4 with FPU core I-bus, D-bus and S-bus
– DMA1 memory bus
– DMA2 memory bus
– DMA2 peripheral bus
– Ethernet DMA bus
– USB OTG HS DMA bus
• Seven slaves:
– Internal Flash memory ICode bus
– Internal Flash memory DCode bus
– Main internal SRAM1 (112 KB)
– Auxiliary internal SRAM2 (16 KB)
– AHB1 peripherals including AHB to APB bridges and APB peripherals
– AHB2 peripherals
–FSMC
The bus matrix provides access from a master to a slave, enabling concurrent access and
efficient operation even when several high-speed peripherals work simultaneously. The 64-
Kbyte CCM (core coupled memory) data RAM is not part of the bus matrix and can be
accessed only through the CPU. This architecture is shown in Figure 1.