Low Peripherals mode.
The BCM2711 has two main addressing schemes: a "Full" 35-bit address bus and a 32-bit "Legacy Master" view as seen by the peripherals (except for "large address" masters). There’s also a "Low Peripherals" mode which modifies the ARM’s view of the peripheral addresses.
The peripheral addresses specified in this document are legacy master addresses. Software accessing peripherals using the DMA engines must use 32-bit legacy master addresses. The Main peripherals are available from 0x7C00_0000 to 0x7FFF_FFFF. Behind the scenes, the VideoCore transparently translates these addresses to the 35-bit 0x4_7nnn_nnnn addresses. So a peripheral described in this document as being at legacy address 0x7Enn_nnnn is available in the 35-bit address space at 0x4_7Enn_nnnn, and visible to the ARM at 0x0_FEnn_nnnn if Low Peripheral mode is enabled.
Statistics: Posted by trejan — Mon Mar 17, 2025 7:19 am