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Commit fe55cb7

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committedMar 18, 2025·
Added clarification about firmware execution from external flash
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‎ports/stm/supervisor/port.c

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@@ -138,7 +138,14 @@ __attribute__((used, naked)) void Reset_Handler(void) {
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__DMB(); /* ARM says to use a DMB instruction before relocating VTOR */
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SCB->VTOR = 0x90000000u; /* We relocate vector table to the QSPI sector 1 */
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__DSB(); /* ARM says to use a DSB instruction just after relocating VTOR */
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/* SystemInit call is not necessary, initializations are done in the H750 special bootloader */
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/*
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Since the STM32H750 microcontroller has only 128kB internal flash,
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CircuitPython has to run from an external flash (QSPI or FMC).
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This means a custom bootloader, like tinyUF2, is needed on the internal
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flash to initialize the clocks, PLLs and (QSPI) controller, and to
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start execution of the firmware from the external flash.
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It also makes the SystemInit() call not necessary for this chip.
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*/
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#else
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SystemInit();
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#endif

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