STM CircleOS forum / Did I do anything wrong on my first Primer1 project?

erna · 2009-10-18 14:09:11

Hello,

having developed applications for Atmel's 8bit microcontrollers for some time now I wanted to try ARM MCUs. The Primer1 seemed like an ideal tool to get started with it but I now realize that programming ARM MCUs is not as easy as I expected it to be. This is why I wanted to show You my first “Hello World” application before flashing it onto the Primer and probably damaging something.

So what I did was downloading the newest version of the ST Standard Peripheral Library (3.1.2) and creating a new Ride project inspired by the GPIO example supplied with the library. I reused their stm32f10x_it.c/h and stm32f10x_conf.h, defined STM32F10X_MD and USE_STDPERIPH_DRIVER and used the startup code supplied with the library.
Since the ST library assumes an external 8 MHz crystal being connected to the MCU but the Primer is equipped with a 12 MHz crystal I changed HSE_Value in “stm32f10x.h” accordingly and replaced “RCC_CFGR_PLLMULL9” with “RCC_CFGR_PLLMULL6” in the following line of the SetSysClockTo72() function in system_stm32f10x.h:

Code:

RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMULL9);

And now at last this is my main.c (which is also mostly a copy of the GPIO example):

Code:

#include "stm32f10x.h"
#include "stm32f10x_conf.h"

GPIO_InitTypeDef GPIO_InitStructure;

void Delay(__IO uint32_t nCount);

int main()
{
    SystemInit();

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB |
                         RCC_APB2Periph_GPIOC, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_All;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
    GPIO_Init(GPIOB, &GPIO_InitStructure);
    GPIO_Init(GPIOC, &GPIO_InitStructure);

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB |
                         RCC_APB2Periph_GPIOC, DISABLE);
  
    /* Enable the GPIO_LED Clock */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    /* Configure the GPIO_LED pin */
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; 
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

    GPIO_Init(GPIOB, &GPIO_InitStructure);

    while(1)
    {
        // LED0 on
        GPIOB->BSRR = GPIO_Pin_8;
        // delay
        Delay(0xAFFFF);
        // LED0 off
        GPIOB->BRR = GPIO_Pin_8;
        // delay
        Delay(0xAFFFF);
    }
}

void Delay(__IO uint32_t nCount)
{
  for(; nCount != 0; nCount--);
}

Compiling it all works well. Have I done anything wrong or forgot something (and thereby putting the Primer hardware at risk)?

In addition to that question I was wondering whether there is any documentation on the peripherals of the STM32F10x family available. If You take a look at the datasheets of Atmel's AVRs every bit of every register controlling the peripherals is described very detailed. Is there anything similar for the STM32F10x?

Best regards

erna · 2009-10-18 19:54:00

Well, my second question has just been answered by finding the documents “STM32F10xxx Cortex-M3 programming manual” and the reference manual for the STM32 family (RM0008) I overlooked earlier.

yrt · 2009-10-19 06:41:57

Effectively the entire description of the STM32 peripehals are in the RM0008 manual.

Concerning the clock configuration, if you want to run at 72 MHz systemclock with a 12 MHz external quartz, you are right to change the line
RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMULL9);

but, you have to declare the macro :
#define SYSCLK_FREQ_72MHz 72000000

In this case the value of HSE_Value is not taken into account.

Anyway, your code seems to be correct, and there is no risk for your Primer hardware.

Yves

erna · 2009-10-19 13:07:30

Thank You very much!

# 1 2009-10-18 14:09:11 Did I do anything wrong on my first Primer1 project?

Did I do anything wrong on my first Primer1 project?

Code:

Code:

# 2 2009-10-18 19:54:00 Did I do anything wrong on my first Primer1 project?

Re: Did I do anything wrong on my first Primer1 project?

# 3 2009-10-19 06:41:57 Did I do anything wrong on my first Primer1 project?

Re: Did I do anything wrong on my first Primer1 project?

# 4 2009-10-19 13:07:30 Did I do anything wrong on my first Primer1 project?

Re: Did I do anything wrong on my first Primer1 project?

Board footer