Sam Walsh / Mbed OS Candle_Simulator

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Fork of PwmOut_HelloWorld by mbed_example

main.cpp@3:55e383869d46, 2017-05-16 (annotated)

Committer:
EmbeddedSam
Date:
Tue May 16 14:21:57 2017 +0000
Revision:
3:55e383869d46
Parent:
1:5160ea45399b 
first commit ;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 0:50d2b9c62765 1 #include "mbed.h"
EmbeddedSam 3:55e383869d46 2 #include <stdio.h>
EmbeddedSam 3:55e383869d46 3 #include <stdlib.h>
EmbeddedSam 3:55e383869d46 4 #include <time.h>
mbedAustin 1:5160ea45399b 5
EmbeddedSam 3:55e383869d46 6 PwmOut output(D2);
EmbeddedSam 3:55e383869d46 7 Serial pc(USBTX, USBRX);
EmbeddedSam 3:55e383869d46 8
EmbeddedSam 3:55e383869d46 9 float random_number;
EmbeddedSam 3:55e383869d46 10
EmbeddedSam 3:55e383869d46 11 void Configure_System_Clocks(void);
mbedAustin 1:5160ea45399b 12
mbed_official 0:50d2b9c62765 13 int main() {
EmbeddedSam 3:55e383869d46 14
EmbeddedSam 3:55e383869d46 15 Configure_System_Clocks();
EmbeddedSam 3:55e383869d46 16 output.period_us(100); // 100 kHz Period PWM Output
EmbeddedSam 3:55e383869d46 17 output.write(0.50); // 50% Duty Cycle
EmbeddedSam 3:55e383869d46 18
EmbeddedSam 3:55e383869d46 19 srand(time(NULL)); // Seed the rand function to intialise it
EmbeddedSam 3:55e383869d46 20
EmbeddedSam 3:55e383869d46 21 while(1){
EmbeddedSam 3:55e383869d46 22 //random_number = (float)rand()/(float)RAND_MAX; // Generate random number between 0 and 1
EmbeddedSam 3:55e383869d46 23 random_number = 0.3;
EmbeddedSam 3:55e383869d46 24 if(random_number <= 0.5f)
EmbeddedSam 3:55e383869d46 25 {
EmbeddedSam 3:55e383869d46 26 output.write(0.5);
EmbeddedSam 3:55e383869d46 27 }
EmbeddedSam 3:55e383869d46 28 else
EmbeddedSam 3:55e383869d46 29 {
EmbeddedSam 3:55e383869d46 30 output.write(0);
EmbeddedSam 3:55e383869d46 31 }
EmbeddedSam 3:55e383869d46 32 }
EmbeddedSam 3:55e383869d46 33 }
EmbeddedSam 3:55e383869d46 34
EmbeddedSam 3:55e383869d46 35 void Configure_System_Clocks(void){
EmbeddedSam 3:55e383869d46 36 PWR->CR |= PWR_CR_VOS_1; //Voltage scale 2
EmbeddedSam 3:55e383869d46 37
EmbeddedSam 3:55e383869d46 38 RCC->APB1ENR |= RCC_APB1ENR_PWREN; //APB1 Clock power enable
EmbeddedSam 3:55e383869d46 39
EmbeddedSam 3:55e383869d46 40 RCC->CR |= RCC_CR_HSEON;
EmbeddedSam 3:55e383869d46 41 while((RCC->CR & RCC_CR_HSERDY) == 0){}; //Wait for HSE Ready
EmbeddedSam 3:55e383869d46 42
EmbeddedSam 3:55e383869d46 43 //RCC->CFGR |= RCC_CFGR_MCO1PRE_0;
EmbeddedSam 3:55e383869d46 44 RCC->CFGR |= RCC_CFGR_MCO1; //MCO1 OUTPUT = 0=,1=0x02
EmbeddedSam 3:55e383869d46 45
EmbeddedSam 3:55e383869d46 46 FLASH->ACR |= FLASH_ACR_PRFTEN; //Enable Prefetch Buffer
EmbeddedSam 3:55e383869d46 47 FLASH->ACR |= FLASH_ACR_ICEN; //Instruction Cache Enable
EmbeddedSam 3:55e383869d46 48 FLASH->ACR |= FLASH_ACR_DCEN; //Data Cache Enable
EmbeddedSam 3:55e383869d46 49 FLASH->ACR |= FLASH_ACR_LATENCY_2WS; //Flash 2 Wait State
EmbeddedSam 3:55e383869d46 50
EmbeddedSam 3:55e383869d46 51 RCC->CFGR |= RCC_CFGR_HPRE_DIV1; //AHB1PRESCALER = HCLK = SYSCLK 1=0x00
EmbeddedSam 3:55e383869d46 52 RCC->CFGR |= RCC_CFGR_PPRE1_DIV2; //APB1PRESCALER = HCLK/2 2=0x04
EmbeddedSam 3:55e383869d46 53 RCC->CFGR |= RCC_CFGR_PPRE2_DIV1; //APB2PRESCALER = HCLK/1
EmbeddedSam 3:55e383869d46 54
EmbeddedSam 3:55e383869d46 55 RCC->CR &= ~RCC_CR_PLLON;
EmbeddedSam 3:55e383869d46 56
EmbeddedSam 3:55e383869d46 57 RCC->PLLCFGR = (4ul | // PLL_M = 4
EmbeddedSam 3:55e383869d46 58 (84ul << 6) | // PLL_N = 84
EmbeddedSam 3:55e383869d46 59 (0ul << 16) | // PLL_P = 2
EmbeddedSam 3:55e383869d46 60 (RCC_PLLCFGR_PLLSRC_HSE) | // PLL_SRC = HSE
EmbeddedSam 3:55e383869d46 61 (7ul << 24)); // PLL_Q = 7
EmbeddedSam 3:55e383869d46 62
EmbeddedSam 3:55e383869d46 63 RCC->CR |= RCC_CR_PLLON; // Enable PLL
EmbeddedSam 3:55e383869d46 64 while((RCC->CR & RCC_CR_PLLRDY) == 0) __NOP(); // Wait till PLL is ready
EmbeddedSam 3:55e383869d46 65
EmbeddedSam 3:55e383869d46 66 RCC->CFGR &= ~RCC_CFGR_SW; // Select PLL as system clock source
EmbeddedSam 3:55e383869d46 67 RCC->CFGR |= RCC_CFGR_SW_PLL;
EmbeddedSam 3:55e383869d46 68 while ((RCC->CFGR & RCC_CFGR_SWS) != RCC_CFGR_SWS_PLL); // Wait till PLL is system clock src
EmbeddedSam 3:55e383869d46 69 //System clock should be setup for 84MHz, lets output this to MCO1
EmbeddedSam 3:55e383869d46 70
EmbeddedSam 3:55e383869d46 71
EmbeddedSam 3:55e383869d46 72 //Setup PA8 MCO1 as GPIO Output
EmbeddedSam 3:55e383869d46 73 RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN; //Enable GPIOA Clock
EmbeddedSam 3:55e383869d46 74 GPIOA->MODER |= GPIO_MODER_MODER8_1; //GPIO_MODER_MODER8_1 = 2 = Alternate Function Pin
EmbeddedSam 3:55e383869d46 75 GPIOA->OTYPER |= (0ul<<8); //Push Pull Output
EmbeddedSam 3:55e383869d46 76 GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR8; //High Speed Output
EmbeddedSam 3:55e383869d46 77 GPIOA->PUPDR |= (0ul << 2*8); //No Pullup Pulldown
EmbeddedSam 3:55e383869d46 78 GPIOA->AFR[1] |= (0ul << 0); //AFRH register holds P8-P15 AF Config, 0x00 = AF0 for PORT8 Which from Datasheet Table 9 = MCO1
mbed_official 0:50d2b9c62765 79 }