Flash banks address ranges for STM32H742(3) devices with 1MB and CubeIDE

[SToma]

Based on Reference Manual of the STM32H742IG (RM0433 Rev 7; Table 16.), Flash memory for 1MB devices is divided in two banks with address ranges 0x800000-0x807FFFF and 0x810000-0x817FFFF. There is 512kB gap between them.

As a test i have created a project in the CubeIDE (1.6.1 with H7 package 1.9.0) for STM32H742IG with big byte array. Generated binary file is without a gap. For example, array addresses fall to this gap.

From listing:

 t = img_map[642000];

 80002de:  4a05       ldr  r2, [pc, #20]  ; (80002f4 <main+0x1c>)

 80002e0:  4b05       ldr  r3, [pc, #20]  ; (80002f8 <main+0x20>)

 80002e2:  4413       add  r3, r2

 80002e4:  781b       ldrb  r3, [r3, #0]

 80002f4:  08001838  .word  0x08001838

 80002f8:  0009cbd0  .word  0x0009cbd0

img_map[642000] is at address 0x809E408 (in gap between banks).

So, is there a gap between banks, and code should handle this? Or there is no gap, and RM is wrong? Or am i miss something?

Regards,

Slavo T.

[TDK]

If you have a chip onhand, can you use STM32CubeProgrammer to read memory from those locations and verify the RM is correct? Seems way odd to have FLASH memory with a gap in the middle. I would guess the RM is wrong, but can't verify it and could be wrong.

[TDK]

FWIW, this table is new in the rev7 manual.

Also, CubeMX generated code thinks the 1MB is contiguous:

> FLASH (rx)   : ORIGIN = 0x08000000, LENGTH = 1024K

[Pavel A.]

Maybe link script generated by Cube for H742 is wrong (copied from H743 which has no gap).

Maybe H742 actually has 1 MB in one of two banks, like some H750's have more than 128K flash, but the extra flash is not guaranteed to work.

Do not try to access it in production code.

--pa

[TDK]

Maybe. I would expect 1MB devices to only have 1MB of flash but could be wrong. Certainly if 2MB is actually present and usable in CubeProgrammer it doesn't help clarify the situation at all.

[SToma]

So, finally i wired up device. And it doesn't help at all, because my device is 2MB. I am able write different values (and then read them) to 0x8000000, 0x8080000, 0x8100000, 0x8180000 addresses.

Seems, i must ask support of STM.

[SToma]

Just a note - H743 devices with 1MB are also with gap (Table 16. Flash memory organization on STM32H742xG/743xG devices).

[SToma]

So, there is an answer from STM - "There is a gap and the 2 banks are not contiguous."

[Khouloud ZEMMELI]

Hi All,

Thanks for raising the point,

It will be internally checked, I'll keep you posted.

Khouloud

[mwb]

Dear ST employees,

can you give us an update on this?

Kind regards