1 | #include "main.h"
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2 |
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3 | GPIO_InitTypeDef GPIO_InitStructure;
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4 | static __IO uint32_t TimingDelayLed1;
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5 | static __IO uint32_t TimingDelayLed2;
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6 |
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7 | int main(void)
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8 | {
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9 | /*!< At this stage the microcontroller clock setting is already configured,
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10 | this is done through SystemInit() function which is called from startup
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11 | file (startup_stm32f2xx.s) before to branch to application main.
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12 | To reconfigure the default setting of SystemInit() function, refer to
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13 | system_stm32f2xx.c file
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14 | */
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15 |
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16 | /* Initialize Leds mounted on STM322xG-EVAL board */
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17 | STM_EVAL_LEDInit(LED1);
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18 | STM_EVAL_LEDInit(LED2);
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19 |
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20 | /* Turn on LED1 and LED3 */
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21 | STM_EVAL_LEDOn(LED1);
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22 | STM_EVAL_LEDOn(LED2);
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23 |
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24 | /* Setup SysTick Timer for 1 msec interrupts.
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25 | ------------------------------------------
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26 | 1. The SysTick_Config() function is a CMSIS function which configure:
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27 | - The SysTick Reload register with value passed as function parameter.
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28 | - Configure the SysTick IRQ priority to the lowest value (0x0F).
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29 | - Reset the SysTick Counter register.
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30 | - Configure the SysTick Counter clock source to be Core Clock Source (HCLK).
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31 | - Enable the SysTick Interrupt.
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32 | - Start the SysTick Counter.
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33 |
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34 | 2. You can change the SysTick Clock source to be HCLK_Div8 by calling the
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35 | SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK_Div8) just after the
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36 | SysTick_Config() function call. The SysTick_CLKSourceConfig() is defined
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37 | inside the misc.c file.
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38 |
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39 | 3. You can change the SysTick IRQ priority by calling the
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40 | NVIC_SetPriority(SysTick_IRQn,...) just after the SysTick_Config() function
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41 | call. The NVIC_SetPriority() is defined inside the core_cm3.h file.
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42 |
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43 | 4. To adjust the SysTick time base, use the following formula:
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44 |
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45 | Reload Value = SysTick Counter Clock (Hz) x Desired Time base (s)
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46 |
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47 | - Reload Value is the parameter to be passed for SysTick_Config() function
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48 | - Reload Value should not exceed 0xFFFFFF
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49 | */
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50 | if (SysTick_Config(SystemCoreClock / 1000))
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51 | {
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52 | /* Capture error */
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53 | while (1);
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54 | }
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55 |
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56 | TimingDelayLed1 = 255;
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57 | TimingDelayLed2 = 127;
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58 |
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59 | while (1)
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60 | {
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61 | __no_operation();
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62 | }
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63 | }
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64 |
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65 | void SysTick_Handler(void)
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66 | {
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67 | if (TimingDelayLed1 != 0x00)
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68 | {
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69 | TimingDelayLed1--;
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70 | }
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71 | else if(TimingDelayLed1 == 0x00)
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72 | {
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73 | TimingDelayLed1 = 255;
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74 | STM_EVAL_LEDToggle(LED1);
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75 | }
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76 |
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77 | if (TimingDelayLed2 != 0x00)
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78 | {
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79 | TimingDelayLed2--;
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80 | }
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81 | else if(TimingDelayLed2 == 0x00)
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82 | {
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83 | TimingDelayLed2 = 127;
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84 | STM_EVAL_LEDToggle(LED2);
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85 | }
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86 |
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87 | }
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