
System and memory overview
RM0351
DocID024597 Rev 5
2
System and memory overview
2.1 System
architecture
The main system consists of 32-bit multilayer AHB bus matrix that interconnects:
•
Up to six masters:
–
Cortex
®
-M4 with FPU core I-bus
–
Cortex
®
-M4 with FPU core D-bus
–
Cortex
®
-M4 with FPU core S-bus
–
DMA1
–
DMA2
–
DMA2D (only for STM32L496xx/4A6xx devices)
•
Up to eight slaves:
–
Internal Flash memory on the ICode bus
–
Internal Flash memory on DCode bus
–
Internal SRAM1 (96 KB for STM32L475xx/476xx/486xx devices, 256 KB for
STM32L496xx/4A6xx devices)
–
Internal SRAM2 (32 KB for STM32L475xx/476xx/486xx devices, 64 KB for
STM32L496xx/4A6xx devices)
–
AHB1 peripherals including AHB to APB bridges and APB peripherals (connected
to APB1 and APB2)
–
AHB2 peripherals
–
Flexible Memory Controller (FMC)
–
Quad SPI memory interface (QUADSPI)
On STM32L475xx/476xx/486xx devices, FMC and QUADSPI slaves are merged into same
port.
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. This
architecture is shown in
for STM32L475xx/476xx/486xx devices, and shown in
for STM32L496xx/4A6xx devices: