2025-08-16 8:32 AM
Hi everyone,
I'm working with an STM32F103C8T6. Even though I haven't programmed any code onto it myself, when I connect with STM32CubeProgrammer, the Registers panel immediately shows “SLEEP” (while on other ST boards it would show “HALTED”). Because of this, I can't perform a Full Chip Erase — the option appears but doesn't work.
Here’s what I’ve tried:
Connected only SWDIO, SWCLK, GND, and 3.3 V (no NRST).
CubeProgrammer shows “SLEEP,” and erase fails.
On other boards, “Connect under reset” works fine and allows erasing.
Possible issues I suspect:
No NRST pin connection → ST-Link can’t halt the MCU before it runs.
Option Bytes might have RDP (Read-Out Protection) enabled.
BOOT0 pin wrongly tied (stuck in System Memory mode).
Some factory test code or previous user code (making MCU go to sleep on reset).
What I tried from forum suggestions:
Tried “Connect under reset” with NRST — this works on other boards but seems not to work here yet.
Any ideas how to force-erase or regain access?
I’d appreciate any advice—including Option Bytes configuration, hardware wiring, or CubeProgrammer settings.
Thanks!
2025-08-17 1:31 PM
Hi,
What st-link you use?
And set connect; software reset, and enable low power modes.
Try to connect, then show, what Cube programmer shows, screen shot.
2025-08-17 3:15 PM
Connect Under Reset from the debug pod expects NRST to be connected to the Target MCU
You can use the BOOTx pins to cause a power-up / reset into System Memory rather than a user program in FLASH sleeping the device or otherwise breaking the debug interface.
Consider have a delaying loop in System Reset to allow debugger time to connect initially
2025-08-18 12:19 AM
ı use stm32f446re nucleo board as stlink,ı can not connect stmf103 with cubeide ,only with cubeprogrammer in hot plug mode,
this is the screenshoot ,only see stm in sleep mode , ı try my nucleo board and ı see halted,is there any chance my stm32f103c8t6 is clone
2025-08-18 1:52 AM
>is there any chance my stm32f103c8t6 is clone
Everything could be a "clone" , but it is very unlikely , as cpu ID (and revision) show same, as on a F103 here:
So connect with : software reset, nrst not needed;
Then look in OptionBytes: rdp not set:
next see in OptionBytes: all (!) sectors have write protection OFF (= checked).
down to 31:
Then full/mass erase should work:
Try.
2025-08-18 10:01 AM
hello again
so when ı checked all option bytes click apply programmer stop working
these are screenshoot when ı try to full erase chip
2025-08-18 10:52 AM
And you looked at all sectors in OptionBytes ?
: all (!) sectors have write protection OFF (= checked).
btw
I also got some new chips from distributor, that had some write protected sectors - no full erase possible.
Until you set all to unprotected.