Diff: main.cpp

Revision:

3:55e383869d46

Parent:

1:5160ea45399b

--- a/main.cpp	Thu Jan 19 10:43:48 2017 -0600
+++ b/main.cpp	Tue May 16 14:21:57 2017 +0000
@@ -1,12 +1,79 @@
 #include "mbed.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
 
-PwmOut led(LED1);
+PwmOut output(D2);
+Serial pc(USBTX, USBRX);
+
+float  random_number;
+
+void Configure_System_Clocks(void);
 
 int main() {
-    // specify period first
-    led.period(4.0f);      // 4 second period
-    led.write(0.50f);      // 50% duty cycle, relative to period
-    //led = 0.5f;          // shorthand for led.write()
-    //led.pulsewidth(2);   // alternative to led.write, set duty cycle time in seconds
-    while(1);
+    
+    Configure_System_Clocks();
+    output.period_us(100);  // 100 kHz Period PWM Output
+    output.write(0.50);    // 50% Duty Cycle
+    
+    srand(time(NULL));     // Seed the rand function to intialise it
+    
+    while(1){
+        //random_number = (float)rand()/(float)RAND_MAX;  // Generate random number between 0 and 1
+        random_number = 0.3;
+        if(random_number <= 0.5f)
+        {
+            output.write(0.5);
+        }
+        else
+        {
+            output.write(0);
+        }
+    }
+}
+
+void Configure_System_Clocks(void){
+    PWR->CR |= PWR_CR_VOS_1;                                                                    //Voltage scale 2
+     
+    RCC->APB1ENR |= RCC_APB1ENR_PWREN;                                              //APB1 Clock power enable
+    
+    RCC->CR |= RCC_CR_HSEON;
+    while((RCC->CR & RCC_CR_HSERDY) == 0){};                                    //Wait for HSE Ready
+    
+  //RCC->CFGR |= RCC_CFGR_MCO1PRE_0;        
+    RCC->CFGR |= RCC_CFGR_MCO1;                                                 //MCO1 OUTPUT = 0=,1=0x02
+        
+    FLASH->ACR |= FLASH_ACR_PRFTEN;                                             //Enable Prefetch Buffer
+    FLASH->ACR |= FLASH_ACR_ICEN;                                                       //Instruction Cache Enable
+    FLASH->ACR |= FLASH_ACR_DCEN;                                                       //Data Cache Enable
+    FLASH->ACR |= FLASH_ACR_LATENCY_2WS;                                            //Flash 2 Wait State
+        
+    RCC->CFGR |= RCC_CFGR_HPRE_DIV1;                                                //AHB1PRESCALER = HCLK = SYSCLK  1=0x00
+    RCC->CFGR |= RCC_CFGR_PPRE1_DIV2;                                               //APB1PRESCALER = HCLK/2  2=0x04
+    RCC->CFGR |= RCC_CFGR_PPRE2_DIV1;                                               //APB2PRESCALER = HCLK/1
+        
+    RCC->CR &= ~RCC_CR_PLLON;
+    
+  RCC->PLLCFGR = (4ul                       |                // PLL_M =  4
+                 (84ul << 6)                |                // PLL_N = 84
+                 (0ul << 16)                |                // PLL_P =  2
+                 (RCC_PLLCFGR_PLLSRC_HSE)   |                // PLL_SRC = HSE
+                 (7ul << 24));                               // PLL_Q =   7
+    
+    RCC->CR |= RCC_CR_PLLON;                                 // Enable PLL
+    while((RCC->CR & RCC_CR_PLLRDY) == 0) __NOP();           // Wait till PLL is ready
+
+    RCC->CFGR &= ~RCC_CFGR_SW;                               // Select PLL as system clock source
+    RCC->CFGR |=  RCC_CFGR_SW_PLL;
+    while ((RCC->CFGR & RCC_CFGR_SWS) != RCC_CFGR_SWS_PLL);  // Wait till PLL is system clock src
+    //System clock should be setup for 84MHz, lets output this to MCO1
+    
+     
+    //Setup PA8 MCO1 as GPIO Output 
+    RCC->AHB1ENR   |= RCC_AHB1ENR_GPIOAEN;                    //Enable GPIOA Clock
+    GPIOA->MODER   |= GPIO_MODER_MODER8_1;                    //GPIO_MODER_MODER8_1 = 2 = Alternate Function Pin
+    GPIOA->OTYPER  |= (0ul<<8);                               //Push Pull Output
+    GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR8;                 //High Speed Output
+    GPIOA->PUPDR     |= (0ul << 2*8);                           //No Pullup Pulldown
+    GPIOA->AFR[1]  |= (0ul << 0);                                           //AFRH register holds P8-P15 AF Config, 0x00 = AF0 for PORT8 Which from Datasheet Table 9 = MCO1                
 }
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