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Can a STM32 be used for external memory?
When you are ready to use external memories in homemade designs, you can use QFP STM32s with at least 144 pins, TSSOP memory chips, and a 4-layer PCB. The STM32’s FMC peripheral can address a few different types of memory.
Why do we need memory mapping for peripheral registers?
Memory-mapping of hardware peripheral registers is a straightforward way to make them accessible to the processor core, as each register is accessible as a memory address. This is both convenient when writing the firmware code, as well as for testing, as we can use a memory mapping specific for unit or integration testing.
Is there way to change how memory is mapped?
There is no way to change how the memory is mapped. In order to execute from a memory it has to be connected to instruction bus of the ARM processor. The Cortex M7 is a bit more complicated than an M4, but the matrix diagram still holds. The bottom of the ARM Cortex M7 up left is the AXIM bus where instruction are fetched.
Are there protocols that can do memory mapping?
Instead there are protocols like FMC and QuadSPI (or QSPI?) where the protocol and external chip specs can function with memory mapping. The linked document above (AN4761) shows examples on how to setup such functionality using SRAM, NAND and other chip types.
What do PTP messages do on the STM32F7?
STM32F7 supports PTP messages for synchronization and acknowledge. A 64-bit register indicates the current value of the system time maintained by the MAC. A pulse-per-second signal (or PPS) can be driven on the Timer 2 so that the timing drift between slave and master clock can be measured.
How much memory does the stm32f723e Discovery Kit use?
PSRAM schematic used by the STM32F723E Discovery Kit. This is actually a 1MB RAM chip, but we can only use 512KB because the A18 address pin is wired to Ground. You can see that this PSRAM chip doesn’t use the CLK, NWAIT or NL signals; since it doesn’t use a clock signal, this will be treated as an asynchronous memory module.
What does a stm32f723ie chip look like?
For our STM32F723IE chip, it looks like: Bank 1 @ 0x60000000: Up to four NOR Flash, PSRAM, or SRAM chips with up to 64MB each. Bank 2 @ 0x70000000: Reserved (SDRAM can be remapped to this address). Bank 3 @ 0x80000000: NAND Flash.