View source for MCBSTM32C/Blinky simple with clock control and backlight dim

=Add to "minimum gpio.h"=
<source lang=c>
typedef unsigned short int uint16_t; 
//General Purpose Timers
#define APB1PERIPH_BASE       PERIPH_BASE
#define TIM3_BASE             (APB1PERIPH_BASE + 0x0400)
typedef struct
{
  __IO uint16_t CR1;
       uint16_t RESERVED0;
  __IO uint16_t CR2;
       uint16_t RESERVED1;
  __IO uint16_t SMCR;
       uint16_t RESERVED2;
  __IO uint16_t DIER;
       uint16_t RESERVED3;
  __IO uint16_t SR;
       uint16_t RESERVED4;
  __IO uint16_t EGR;
       uint16_t RESERVED5;
  __IO uint16_t CCMR1;
       uint16_t RESERVED6;
  __IO uint16_t CCMR2;
       uint16_t RESERVED7;
  __IO uint16_t CCER;
       uint16_t RESERVED8;
  __IO uint16_t CNT;
       uint16_t RESERVED9;
  __IO uint16_t PSC;
       uint16_t RESERVED10;
  __IO uint16_t ARR;
       uint16_t RESERVED11[3];
  __IO uint16_t CCR1;
       uint16_t RESERVED12;
  __IO uint16_t CCR2;
       uint16_t RESERVED13;
  __IO uint16_t CCR3;
       uint16_t RESERVED14;
  __IO uint16_t CCR4;
       uint16_t RESERVED15[3];
  __IO uint16_t DCR;
       uint16_t RESERVED16;
  __IO uint16_t DMAR;
       uint16_t RESERVED17;
} TIM_GP_TypeDef;

#define TIM3                  ((TIM_GP_TypeDef *) TIM3_BASE    )
</source>

=backlight.c=
<source lang=c>
#include "minimum gpio.h"

/*
Example 2:
==========
Using timer 3 to Dim the Backlight in Display
 
Mode : Continues PWM mode to PB0. Section 15.3.9 page 370
    For details see: http://mars.tekkom.dk/mediawiki/index.php/STM32F107VC/Using_MCBQVGA-TS-Display-v12
 
Caveats: Assumes TIMxCLK = 72 MHz (See RCC - Reset And Clock Control)
*/
 
void tim3init( void ) {
	volatile int i;
	i = GPIOB->CRL & 0xfffffff0;
	GPIOB->CRL = i | 0xa;
	//GPIOB->CRL |= 0xa;  // Set PB0 as Alternate function Push-Pull 
	RCC->APB1ENR |= 2; //Enable timer 3 clock 	(RCC->APB1ENR bit 1 = 1)
 
 
	TIM3->PSC = 72;	  // Prescaler: With timer 3 input clock 72 Mhz divide by 72 to 1 Mhz
	TIM3->ARR = 1000; // Auto Reload Register set to 1000 divide 1Mhz/1000 = 1 Khz
	TIM3->CCR3 = 100; //Compare Regisger for channel 3
	TIM3->CCMR2 |= 7 << 4; //PWM mode 1
	TIM3->CCMR2 |= 1 << 3;
	TIM3->EGR |= 1; //Update generate
	TIM3->CCER |= 1<<8; //Polarity
	TIM3->CCER |= 1<<9;
	TIM3->CR1 |= 1;
}
 
/* Change Display Backlight Intensity
 input: 0 - 17 ( 0 = 0% backlight (All dark) to 17 = 100% backlight (Brigth)
 Caveats: No errorcontrol
             When 0 the timer should be turned off and the backlight turned off (PB0=0)
             when 17 the timer should be turned off and the backlight turned on (PB0=1)
*/
void backlight( int intensity ) {
	int disvalarr[] = {0,5,10,15,25,35,50,65,80,100,120,150,200,300,400,600,800,1000};
	TIM3->CCR3 = disvalarr[intensity];
}
</source>
=Last=
==Step 1==
Make a '''backlight.h''' and include it in '''main.c'''
==Step 2==
*use the '''user''' button to increase backlight from 0 to 17 using the '''backlight()''' function
*use '''tamper''' button to decrease backlight from 17 to 0 using the '''backlight()''' function