STM32: can use built-in bootloader to upload my code, but nothing happens

[allanvv]

I made a board with an STM32F103C8T6. I can successfully use the UART to program and verify the on-board flash memory with the built-in bootloader. But then when I reset and I boot into flash, nothing works.

My code just turns on/off a GPIO that I'm monitoring with a scope. I've verified that the external clock is operating properly (8MHz).

It seems by default that it uses the internal oscillator, so I tried to set it to use the external oscillator by uncommenting "#define SYSCLK_FREQ_HSE HSE_Value" but still nothing happens on reset.

Here's my code:

int main(void) {
	SystemInit();

	GPIO_InitTypeDef GPIO_InitStructure;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_15;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
	GPIO_Init(GPIOA, &GPIO_InitStructure);

	GPIO_WriteBit(GPIOA, GPIO_Pin_15, 1);

	while (1) {
		GPIO_WriteBit(GPIOA, GPIO_Pin_15, 1);
		GPIO_WriteBit(GPIOA, GPIO_Pin_15, 0);

	}
}

edit: This is with an arm gcc 4.5.2. I've used this toolchain successfully on an STR7 board in the past. I've also tried with CodeSourcery's toolchain but still no results.

 

[anotherbrick]

can you try this ?

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

GPIOA->BSRR = GPIO_Pin_15;
GPIOA->BRR = GPIO_Pin_15;

 

[allanvv]

Turns out the issue was in the linker script and startup assembly code. I tried the ones used in these projects: **broken link removed**

and it worked perfectly.

 

[mindthomas]

Have you remembered to set up the clock and the periphirals clock correctly?
I can recommend you to take a look at theese two blog posts about Clock Setup, for both internal and external clock.
TKJ Electronics » STM32 – Internal 8MHz Clock Setup Routine
TKJ Electronics » STM32 – Overclocking

You can also download my Template project, which includes a couple of different setup routines, which makes it a lot easier to get started: **broken link removed**

 

[allanvv]

Hi TKJ - thanks, those links are helpful.

 

[mindthomas]

Great
I hope your project goes well!

 

[allanvv]

One thing -- why do you state that the clock speed when running from the internal oscillator is limited to 36MHz? You can set the multiplier to 16x, and then it'll run at 64MHz. I couldn't find anything in the datasheet that has a different max frequency for internal vs external oscillator. Also in the supply current page, one of the tests they do is for 64MHz internal oscillator.

 

[mindthomas]

Yeah, you can set the multiplier to 16x, but we haven't had any success with this - the STM32 got unstable or wasn't even able to run!