Busmatrix - STMicroelectronics RM0365 Reference Manual

RM0365
3.1.5

BusMatrix

The BusMatrix manages the access arbitration between Masters. The arbitration uses a
Round Robin algorithm. The BusMatrix is composed of five masters (CPU AHB, System
bus, DCode bus, ICode bus, DMA1&2 bus) and seven slaves (FLITF, SRAM, AHB2GPIO
and AHB2APB1/2 bridges, and ADCs).
AHB/APB bridges
The two AHB/APB bridges provide full synchronous connections between the AHB and the
2 APB buses. APB1 is limited to 36 MHz, APB2 operates at full speed (72 MHz).
Refer to
address mapping of the peripherals connected to this bridge.
After each device reset, all peripheral clocks are disabled (except for the SRAM and FLITF).
Before using a peripheral user has to enable its clock in the RCC_AHBENR,
RCC_APB2ENR or RCC_APB1ENR register.
When a 16- or 8-bit access is performed on an APB register, the access is transformed into
a 32-bit access: the bridge duplicates the 16- or 8-bit data to feed the 32-bit vector.
Section 3.2.2: Memory map and register boundary addresses on page 47
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