stm32/isr: Add option to run flash & uart isr function from ram.

This allows uart rx to function while flash erase/writes operations are under way, preventing lost data so long as it fits in the uart rx buffer. Enable in mpconfigboard.mk: MICROPY_USE_RAM_ISR_UART_FLASH_FN = 1 Signed-off-by: Andrew Leech <[email protected]>
andrewleech · Aug 23, 2024 · fa37197 · fa37197
1 parent 6c3dc0c
commit fa37197
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Showing 28 changed files with 109 additions and 48 deletions.
diff --git a/ports/stm32/Makefile b/ports/stm32/Makefile
@@ -143,7 +143,15 @@ CFLAGS += -DMICROPY_FLOAT_IMPL=MICROPY_FLOAT_IMPL_FLOAT
 CFLAGS += -fsingle-precision-constant
 endif
 
-LDFLAGS += -nostdlib -L $(LD_DIR) $(addprefix -T,$(LD_FILES)) -Wl,-Map=$(@:.elf=.map) -Wl,--cref
+# Configure linker include dir for ram/rom isr support
+ifeq ($(MICROPY_HW_ENABLE_ISR_UART_FLASH_FUNCS_IN_RAM),1)
+CFLAGS += -DMICROPY_HW_ENABLE_ISR_UART_FLASH_FUNCS_IN_RAM=1
+LD_ISR_DIR = boards/common_isr_ram
+else
+LD_ISR_DIR = boards/common_isr_rom
+endif
+
+LDFLAGS += -nostdlib -L $(LD_DIR) -L $(LD_ISR_DIR) $(addprefix -T,$(LD_FILES)) -Wl,-Map=$(@:.elf=.map) -Wl,--cref
 LDFLAGS += -Wl,--defsym=_estack_reserve=8
 LIBS += "$(shell $(CC) $(CFLAGS) -print-libgcc-file-name)"
 
@@ -465,7 +473,8 @@ OBJ += $(GEN_PINS_SRC:.c=.o)
 # Don't use -O3 with this file because gcc tries to optimise memset in terms of itself.
 $(BUILD)/shared/libc/string0.o: COPT += -O2
 
-# We put several files into the first 16K section with the ISRs.
+ifneq ($(MICROPY_HW_ENABLE_ISR_UART_FLASH_FUNCS_IN_RAM),1)
+# If MBOOT or RAM_IFS is not used we put several files into the first 16K section with the ISRs.
 # If we compile these using -O0 then it won't fit. So if you really want these
 # to be compiled with -O0, then edit boards/common.ld (in the .isr_vector section)
 # and comment out the following lines.
@@ -474,6 +483,7 @@ $(filter $(PY_BUILD)/../extmod/vfs_fat_%.o, $(PY_O)): COPT += -Os
 $(PY_BUILD)/formatfloat.o: COPT += -Os
 $(PY_BUILD)/parsenum.o: COPT += -Os
 $(PY_BUILD)/mpprint.o: COPT += -Os
+endif
 
 all: $(TOP)/lib/stm32lib/README.md all_main $(BUILD)/firmware.hex
 
@@ -557,7 +567,7 @@ TEXT0_ADDR ?= 0x08000000
 ifeq ($(TEXT1_ADDR),)
 # No TEXT1_ADDR given so put all firmware at TEXT0_ADDR location
 
-TEXT0_SECTIONS ?= .isr_vector .text .data .ARM
+TEXT0_SECTIONS ?= .isr_vector .isr_extratext .text .data .ARM
 
 deploy-stlink: $(BUILD)/firmware.bin
 	$(call RUN_STLINK,$^,$(TEXT0_ADDR))
@@ -574,7 +584,7 @@ $(BUILD)/firmware.dfu: $(BUILD)/firmware.bin
 else
 # TEXT0_ADDR and TEXT1_ADDR are specified so split firmware between these locations
 
-TEXT0_SECTIONS ?= .isr_vector
+TEXT0_SECTIONS ?= .isr_vector .isr_extratext
 TEXT1_SECTIONS ?= .text .data .ARM
 
 deploy-stlink: $(BUILD)/firmware0.bin $(BUILD)/firmware1.bin

diff --git a/ports/stm32/boards/PYBD_SF2/f722_qspi.ld b/ports/stm32/boards/PYBD_SF2/f722_qspi.ld
@@ -19,7 +19,6 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 512K
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 32K     /* sectors 0,1 */
     FLASH_APP (rx)  : ORIGIN = 0x08008000, LENGTH = 480K    /* sectors 2-7 */
     FLASH_EXT (rx)  : ORIGIN = 0x90000000, LENGTH = 2048K   /* external QSPI */
     RAM (rwx)       : ORIGIN = 0x20000000, LENGTH = 256K    /* DTCM+SRAM1+SRAM2 */

diff --git a/ports/stm32/boards/PYBD_SF6/f767.ld b/ports/stm32/boards/PYBD_SF6/f767.ld
@@ -17,7 +17,6 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 2048K
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 32K     /* sector 0, 32K */
     FLASH_APP (rx)  : ORIGIN = 0x08008000, LENGTH = 2016K   /* sectors 1-11 3x32K 1*128K 7*256K */
     FLASH_EXT (rx)  : ORIGIN = 0x90000000, LENGTH = 2048K   /* external QSPI */
     RAM (rwx)       : ORIGIN = 0x20000000, LENGTH = 512K    /* DTCM=128k, SRAM1=368K, SRAM2=16K */

diff --git a/ports/stm32/boards/STM32F769DISC/f769_qspi.ld b/ports/stm32/boards/STM32F769DISC/f769_qspi.ld
@@ -40,6 +40,7 @@ _heap_end = _sstack;
 
 ENTRY(Reset_Handler)
 
+REGION_ALIAS("FLASH_ISR", FLASH_APP);
 REGION_ALIAS("FLASH_COMMON", FLASH_APP);
 
 SECTIONS

diff --git a/ports/stm32/boards/common_basic.ld b/ports/stm32/boards/common_basic.ld
@@ -12,6 +12,7 @@
 
 ENTRY(Reset_Handler)
 
+REGION_ALIAS("FLASH_ISR", FLASH);
 REGION_ALIAS("FLASH_COMMON", FLASH);
 
 /* define output sections */

diff --git a/ports/stm32/boards/common_bl.ld b/ports/stm32/boards/common_bl.ld
@@ -12,6 +12,7 @@
 
 ENTRY(Reset_Handler)
 
+REGION_ALIAS("FLASH_ISR", FLASH_APP);
 REGION_ALIAS("FLASH_COMMON", FLASH_APP);
 
 /* define output sections */

diff --git a/ports/stm32/boards/common_blifs.ld b/ports/stm32/boards/common_blifs.ld
@@ -12,6 +12,7 @@
 
 ENTRY(Reset_Handler)
 
+REGION_ALIAS("FLASH_ISR", FLASH_TEXT);
 REGION_ALIAS("FLASH_COMMON", FLASH_TEXT);
 
 /* define output sections */

diff --git a/ports/stm32/boards/common_ifs.ld b/ports/stm32/boards/common_ifs.ld
@@ -13,36 +13,14 @@
 
 ENTRY(Reset_Handler)
 
+REGION_ALIAS("FLASH_ISR", FLASH_START);
 REGION_ALIAS("FLASH_COMMON", FLASH_TEXT);
 
 /* define output sections */
 SECTIONS
 {
-    /* The startup code goes first into FLASH */
-    .isr_vector :
-    {
-        . = ALIGN(4);
-        KEEP(*(.isr_vector)) /* Startup code */
-
-        /* This first flash block is 16K and the isr vectors only take up
-           about 400 bytes. So we pull in a couple of object files to pad it
-           out. */
-
-        . = ALIGN(4);
-
-        /* NOTE: If you update the list of files contained in .isr_vector,
-                 then be sure to also update smhal/Makefile where it forcibly
-           builds each of these files with -Os */
-
-        */ff.o(.text*)
-        */vfs_fat_*.o(.text*)
-        */py/formatfloat.o(.text*)
-        */py/parsenum.o(.text*)
-        */py/mpprint.o(.text*)
-
-        . = ALIGN(4);
-    } >FLASH_ISR
-
+    INCLUDE common_isr.ld
+    INCLUDE common_isr_extratext.ld
     INCLUDE common_text.ld
     INCLUDE common_extratext_data_in_flash.ld
     INCLUDE common_bss_heap_stack.ld

diff --git a/ports/stm32/boards/common_isr_ram/common_isr.ld b/ports/stm32/boards/common_isr_ram/common_isr.ld
@@ -0,0 +1,36 @@
+/* This linker script fragment is intended to be included in SECTIONS. */
+
+/* The startup code goes first into FLASH */
+.isr_vector :
+{
+    . = ALIGN(4);
+    __isr_vector_ram_start = .;
+
+    KEEP(*(.isr_vector)) /* Startup code */
+
+    /* These functions need to run from ram to enable uart
+       reception during flash erase/write operations.
+       Defining them here ensures they're copied from
+       flash (in main.c) along with the isr_vector above.
+    */
+    . = ALIGN(4);
+    *(.text.pendsv_kbd_intr)
+    *(.text.pendsv_schedule_dispatch)
+    *(.text.storage_systick_callback)
+    *(.text.SysTick_Handler)
+    *(.text.uart_irq_handler)
+    *(.text.UART*_IRQHandler)
+    *(.text.USART*_IRQHandler)
+    *(.text.FLASH_PageErase)
+    *(.text.FLASH_SectorErase)
+    *(.text.FLASH_WaitForLastOperation)
+    *(.text.HAL_FLASHEx_Erase)
+    *(.text.HAL_GetTick)
+
+    __isr_vector_ram_end = .;
+    . = ALIGN(4);
+
+} >RAM AT >FLASH_ISR
+
+/* Used by the start-up code to initialise data */
+__isr_vector_flash_addr = LOADADDR(.isr_vector);
diff --git a/ports/stm32/boards/common_isr_ram/common_isr_extratext.ld b/ports/stm32/boards/common_isr_ram/common_isr_extratext.ld
diff --git a/ports/stm32/boards/common_isr.ld → ...stm32/boards/common_isr_rom/common_isr.ld b/ports/stm32/boards/common_isr.ld → ...stm32/boards/common_isr_rom/common_isr.ld
@@ -6,4 +6,4 @@
     . = ALIGN(4);
     KEEP(*(.isr_vector)) /* Startup code */
     . = ALIGN(4);
-} >FLASH_COMMON
+} >FLASH_ISR
diff --git a/ports/stm32/boards/common_isr_rom/common_isr_extratext.ld b/ports/stm32/boards/common_isr_rom/common_isr_extratext.ld
@@ -0,0 +1,24 @@
+/* This linker script fragment is intended to be included in SECTIONS when
+   common_ifs.ld is used with common_isr.ld
+. */
+
+.isr_extratext :
+{
+    . = ALIGN(4);
+
+    /* This first flash block is 16K and the isr vectors only take up
+        about 400 bytes. So we pull in a couple of object files to pad it
+        out and save flash space in later blocks.
+
+        NOTE: If you update the list of files contained her in .isr_extratext
+        then be sure to also update stm32/Makefile where it builds each of
+        these files with -Os to keep this section as compact as possible.
+    */
+    */ff.o(.text*)
+    */vfs_fat_*.o(.text*)
+    */py/formatfloat.o(.text*)
+    */py/parsenum.o(.text*)
+    */py/mpprint.o(.text*)
+
+    . = ALIGN(4);
+} >FLASH_ISR
diff --git a/ports/stm32/boards/stm32f401xd.ld b/ports/stm32/boards/stm32f401xd.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 384K /* entire flash */
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
     FLASH_FS (rx)   : ORIGIN = 0x08004000, LENGTH = 64K /* sectors 1,2,3,4: 16k+16k+16k+16k(of 64k)=64k */
     FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 256K /* sectors 5,6 are 128K */
     RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 80K

diff --git a/ports/stm32/boards/stm32f401xe.ld b/ports/stm32/boards/stm32f401xe.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 512K /* entire flash */
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
     FLASH_FS (rx)   : ORIGIN = 0x08004000, LENGTH = 64K /* sectors 1,2,3,4: 16k+16k+16k+16k(of 64k)=64k */
     FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 384K /* sectors 5,6,7 are 128K */
     RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 80K

diff --git a/ports/stm32/boards/stm32f405.ld b/ports/stm32/boards/stm32f405.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 1024K /* entire flash */
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
     FLASH_FS (rx)   : ORIGIN = 0x08004000, LENGTH = 112K /* sectors 1,2,3,4 are for filesystem */
     FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 896K /* sectors 5,6,7,8,9,10,11 */
     CCMRAM (xrw)    : ORIGIN = 0x10000000, LENGTH = 64K

diff --git a/ports/stm32/boards/stm32f411.ld b/ports/stm32/boards/stm32f411.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 512K /* entire flash */
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
     FLASH_FS (rx)   : ORIGIN = 0x08004000, LENGTH = 64K /* sectors 1,2,3,4: 16k+16k+16k+16k(of 64k)=64k */
     FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 384K /* sectors 5,6,7 are 128K */
     RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 112K

diff --git a/ports/stm32/boards/stm32f412zx.ld b/ports/stm32/boards/stm32f412zx.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 1024K /* entire flash */
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
     FLASH_FS (rx)   : ORIGIN = 0x08004000, LENGTH = 64K /* sectors 1,2,3,4: 16k+16k+16k+16k(of 64k)=64k */
     FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 896K /* sectors 5,6,7,8,9,10,11 are 128K */
     RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 240K

diff --git a/ports/stm32/boards/stm32f413xg.ld b/ports/stm32/boards/stm32f413xg.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 1024K /* entire flash */
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
     FLASH_FS (rx)   : ORIGIN = 0x08004000, LENGTH = 176K /* sectors 1,2,3 are 16K, 4 is 64K, 5 is 128K (64K used) for filesystem */
     FLASH_FS2 (rx)  : ORIGIN = 0x08040000, LENGTH = 64K /* sector 6 is 128K (64K used) for filesystem, Total filesystem 240K */
     FLASH_TEXT (rx) : ORIGIN = 0x08060000, LENGTH = 640K /* sectors 7,8,9,10,11  are 128K*/

diff --git a/ports/stm32/boards/stm32f413xh.ld b/ports/stm32/boards/stm32f413xh.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 1536K /* entire flash */
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
     FLASH_FS (rx)   : ORIGIN = 0x08004000, LENGTH = 176K /* sectors 1,2,3 are 16K, 4 is 64K, 5 is 128K (64K used) for filesystem */
     FLASH_FS2 (rx)  : ORIGIN = 0x08040000, LENGTH = 64K /* sector 6 is 128K (64K used) for filesystem, Total filesystem 240K */
     FLASH_TEXT (rx) : ORIGIN = 0x08060000, LENGTH = 1152K /* sectors 7,8,9,10,11,12,13,14,15  are 128K*/

diff --git a/ports/stm32/boards/stm32f427xi.ld b/ports/stm32/boards/stm32f427xi.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 2048K /* entire flash */
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH =   16K /* sector 0, 16 KiB */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH =   16K /* sector 0, 16 KiB */
     FLASH_FS (rx)   : ORIGIN = 0x08004000, LENGTH =  112K /* sectors 1-4: 3*16K+64K */
     FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH =  896K /* sectors 5-11 are 128K */
     CCMRAM (xrw)    : ORIGIN = 0x10000000, LENGTH =   64K

diff --git a/ports/stm32/boards/stm32f429.ld b/ports/stm32/boards/stm32f429.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 2048K /* entire flash */
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 16K /* sector 0, 16 KiB */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 16K /* sector 0, 16 KiB */
     FLASH_FS (rx)   : ORIGIN = 0x08004000, LENGTH = 112K /* sectors 1-4: 3*16K+64K */
     FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 896K /* sectors 5-11 are 128K */
     CCMRAM (xrw)    : ORIGIN = 0x10000000, LENGTH = 64K

diff --git a/ports/stm32/boards/stm32f439.ld b/ports/stm32/boards/stm32f439.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 2048K /* entire flash */
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 16K /* sector 0 */
     FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 896K /* sectors 5-11 are 128K */
     FLASH_FS (rx)   : ORIGIN = 0x08100000, LENGTH = 192K /* sectors 12-15 are 16K, 16 is 64K, 17 is 128K (64K used) */
     FLASH_FS2 (rx)  : ORIGIN = 0x08140000, LENGTH = 64K /* sector 18 is 128K (64K used) */

diff --git a/ports/stm32/boards/stm32f722.ld b/ports/stm32/boards/stm32f722.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 512K
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 16K     /* sector 0, 16K */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 16K     /* sector 0, 16K */
     FLASH_FS (r)    : ORIGIN = 0x08004000, LENGTH = 112K    /* sectors 1-4 3*16KiB 1*64KiB*/
     FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 384K    /* sectors 5-7 3*128KiB = 384K */
     DTCM (xrw)      : ORIGIN = 0x20000000, LENGTH = 64K     /* Used for storage cache */

diff --git a/ports/stm32/boards/stm32f746.ld b/ports/stm32/boards/stm32f746.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 1024K
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 32K     /* sector 0, 32K */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 32K     /* sector 0, 32K */
     FLASH_FS (r)    : ORIGIN = 0x08008000, LENGTH = 96K     /* sectors 1, 2, 3 (32K each) */
     FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 896K    /* sectors 4-7 1*128Kib 3*256KiB = 896K */
     DTCM (xrw)      : ORIGIN = 0x20000000, LENGTH = 64K     /* Used for storage cache */

diff --git a/ports/stm32/boards/stm32f767.ld b/ports/stm32/boards/stm32f767.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 2048K
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 32K     /* sector 0, 32K */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 32K     /* sector 0, 32K */
     FLASH_APP (rx)  : ORIGIN = 0x08008000, LENGTH = 2016K   /* sectors 1-11 3x32K 1*128K 7*256K */
     FLASH_FS (r)    : ORIGIN = 0x08008000, LENGTH = 96K     /* sectors 1, 2, 3 (32K each) */
     FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 896K    /* sectors 4-7 1*128Kib 3*256KiB = 896K */

diff --git a/ports/stm32/boards/stm32f769.ld b/ports/stm32/boards/stm32f769.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 1024K
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 32K     /* sector 0, 32K */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 32K     /* sector 0, 32K */
     FLASH_FS (r)    : ORIGIN = 0x08008000, LENGTH = 96K     /* sectors 1, 2, 3 (32K each) */
     FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 896K    /* sectors 4-7 1*128Kib 3*256KiB = 896K */
     DTCM (xrw)      : ORIGIN = 0x20000000, LENGTH = 128K    /* Used for storage cache */

diff --git a/ports/stm32/boards/stm32h7b3.ld b/ports/stm32/boards/stm32h7b3.ld
@@ -6,7 +6,7 @@
 MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 2048K
-    FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 128K    /* sector 0, 128K */
+    FLASH_START (rx): ORIGIN = 0x08000000, LENGTH = 128K    /* sector 0, 128K */
     FLASH_FS (r)    : ORIGIN = 0x08020000, LENGTH = 128K    /* sector 1, 128K */
     FLASH_TEXT (rx) : ORIGIN = 0x08040000, LENGTH = 1792K   /* sectors 6*128 + 8*128 */
     DTCM (xrw)      : ORIGIN = 0x20000000, LENGTH = 128K    /* Used for storage cache */

diff --git a/ports/stm32/main.c b/ports/stm32/main.c
@@ -303,10 +303,21 @@ void stm32_main(uint32_t reset_mode) {
     // Low-level MCU initialisation.
     stm32_system_init();
 
-    #if !defined(STM32F0) && defined(MICROPY_HW_VTOR)
+    #if !defined(STM32F0)
+    #if MICROPY_HW_ENABLE_ISR_UART_FLASH_FUNCS_IN_RAM
+    // Copy IRQ vector table to RAM and point VTOR there
+    extern uint32_t __isr_vector_flash_addr, __isr_vector_ram_start, __isr_vector_ram_end;
+    size_t __isr_vector_size = (&__isr_vector_ram_end - &__isr_vector_ram_start) * sizeof(uint32_t);
+    memcpy(&__isr_vector_ram_start, &__isr_vector_flash_addr, __isr_vector_size);
+    SCB->VTOR = (uint32_t)&__isr_vector_ram_start;
+    #else
+    #if defined(MICROPY_HW_VTOR)
     // Change IRQ vector table if configured differently
     SCB->VTOR = MICROPY_HW_VTOR;
     #endif
+    #endif
+    #endif
+
 
     #if __CORTEX_M != 33
     // Enable 8-byte stack alignment for IRQ handlers, in accord with EABI