#include "stm32f4xx.h"
#include "stm32f4xx_rcc.c"
#include "stm32f4xx_gpio.c"
#include "stm32f4xx_tim.c"
#include "LCD2x16.c" 

void GPIOAinit_TIM2_ETR(void)   {
GPIO_InitTypeDef          GPIO_InitStructure;

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE); 
  
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource15, GPIO_AF_TIM2);  // PA15:TIM2_Ch1/ETR

  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_15;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;
  //GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;
  //GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; 
  //GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);   
}

void TIM2init_counter(void) {       // counting from ETR
TIM_TimeBaseInitTypeDef   TIM_TimeBaseInitStructure;
  
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,  ENABLE);
  TIM_TimeBaseInitStructure.TIM_Prescaler = 0;
  TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInitStructure.TIM_Period = 100000;
  TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
  //TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;
  TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure);
  
  TIM_ETRClockMode2Config(TIM2, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_NonInverted, 0x00);
  
  TIM_Cmd(TIM2, ENABLE);
}

int main ()  {
  GPIOAinit_TIM2_ETR(); // GPIO clock enable, digital pin definitions
  TIM2init_counter();   // Timer 2 as counter: ETR input
  LCD_init();           // Init LCD
  LCD_string("TIM2 counter ETR", 0);      // write title
  
  // waste time - indefinite
  while (1) {
    LCD_uInt32(TIM2->CNT, 0x40, 0x01);          // show counts
    for (int i = 0; i < 1000000; i++)   {};     // waste time
  };
}