Diff: ST_L152_32MHZ.cpp

Revision:

2:9e2ba1d93567

Parent:

1:bdeac50afe1a

Child:

3:1e82f1f333ad

--- a/ST_L152_32MHZ.cpp	Tue Mar 11 21:03:03 2014 +0000
+++ b/ST_L152_32MHZ.cpp	Wed Mar 19 18:07:11 2014 +0000
@@ -30,28 +30,71 @@
 {
     uint32_t PLLStartUpCounter = 0,PLLStatus = 0,error;
 
-    if(external == 0) {                                               // internal Oscillator
-        RCC_PLLConfig(RCC_PLLSource_HSI,RCC_PLLMul_6,RCC_PLLDiv_3);   // setup pll to 96MHz to use USB
-    } else {
-        RCC_HSEConfig(RCC_HSE_ON);                                    // start external crystal osc.
+
+/* Enable 64-bit access */
+    FLASH->ACR |= FLASH_ACR_ACC64;
+
+    /* Enable Prefetch Buffer */
+    FLASH->ACR |= FLASH_ACR_PRFTEN;
+
+    /* Flash 1 wait state */
+    FLASH->ACR |= FLASH_ACR_LATENCY;
+    
+    /* Power enable */
+    RCC->APB1ENR |= RCC_APB1ENR_PWREN;
+  
+    /* Select the Voltage Range 1 (1.8 V) */
+    PWR->CR = PWR_CR_VOS_0;
+  
+    /* Wait Until the Voltage Regulator is ready */
+    while((PWR->CSR & PWR_CSR_VOSF) != RESET)
+    {
+    }
+      
+    /* HCLK = SYSCLK /1*/
+    RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
+    /* PCLK2 = HCLK /1*/
+    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
+    
+    /* PCLK1 = HCLK /1*/
+    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV1;
+  
+    /*  PLL configuration */
+    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLMUL |
+                                        RCC_CFGR_PLLDIV));
+                                        
+    if(external == 0){                                                                        
+        RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSI | RCC_CFGR_PLLMUL6 | RCC_CFGR_PLLDIV3);
+        }
+    else{
+        RCC_HSEConfig(RCC_HSE_ON);                // start external crystal osc.
         error = RCC_WaitForHSEStartUp();
         if(error == ERROR ) { // no external crystal
             return(EXT_ERR);
-        }
-        RCC_PLLConfig(RCC_PLLSource_HSE,RCC_PLLMul_12,RCC_PLLDiv_3);   // setup pll to 96MHz to use USB
-    }
-    RCC_PLLCmd(ENABLE);                                                // switch on pll
+            }    
+        RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMUL12 | RCC_CFGR_PLLDIV3);    
+        }    
+
+    /* Enable PLL */
+    RCC->CR |= RCC_CR_PLLON;
+
+    /* Wait till PLL is ready */
     do {
         PLLStatus = RCC->CR & RCC_CR_PLLRDY;
     } while((PLLStatus == 0) && (PLLStartUpCounter < PLL_STARTUP_TIMEOUT)); // wait for pll
     if(PLLStatus == 0) {
         return(PLL_ERR);
     }
-    FLASH_SetLatency(FLASH_Latency_1);
-    FLASH_PrefetchBufferCmd(ENABLE);
-    FLASH_ReadAccess64Cmd(ENABLE);
-    RCC_HCLKConfig(RCC_SYSCLK_Div2);
-    RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);  // switch to 32 MHz clock
+
+    /* Select PLL as system clock source */
+    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
+    RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;
+
+    /* Wait till PLL is used as system clock source */
+    while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)RCC_CFGR_SWS_PLL)
+    {
+    }
     SystemCoreClockUpdate();                    // update SystemCoreClock var
     return(OK);
-}
\ No newline at end of file
+}
+