Diff: ST_L152_32MHZ.cpp

Revision:

1:bdeac50afe1a

Parent:

0:84e23a19e37d

Child:

2:9e2ba1d93567

--- a/ST_L152_32MHZ.cpp	Tue Mar 11 20:34:57 2014 +0000
+++ b/ST_L152_32MHZ.cpp	Tue Mar 11 21:03:03 2014 +0000
@@ -1,21 +1,32 @@
-
-
+/* mbed library for the ST NUCLEO board L152RE 
+ * to change the CPU clock to 32 MHz
+ * A pll clock of 96 MHz is used to enable USB  
+ *
+ * Copyright (c) 2014 Peter Drescher - DC2PD
+ * Released under the MIT License: http://mbed.org/license/mit
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+ 
 #include "stm32l1xx.h"
 #include "stm32l1xx_flash.h"
 #include "stm32l1xx_rcc.h"
 #include "ST_L152_32MHZ.h"
 
-// set cpu clock to 32MHz
-
-
-
+// only the constructor  
 L152_init32::L152_init32(unsigned int external){
-    clk_err = setup_clock_32MHZ(external);
+    Status = setup_clock_32MHZ(external);
     }
 
 #define PLL_STARTUP_TIMEOUT 0x5000
 
-int L152_init32::setup_clock_32MHZ(int external)
+ClockStatus L152_init32::setup_clock_32MHZ(int external)
 {
     uint32_t PLLStartUpCounter = 0,PLLStatus = 0,error;
 
@@ -25,7 +36,7 @@
         RCC_HSEConfig(RCC_HSE_ON);                                    // start external crystal osc.
         error = RCC_WaitForHSEStartUp();
         if(error == ERROR ) { // no external crystal
-            return(0);
+            return(EXT_ERR);
         }
         RCC_PLLConfig(RCC_PLLSource_HSE,RCC_PLLMul_12,RCC_PLLDiv_3);   // setup pll to 96MHz to use USB
     }
@@ -34,7 +45,7 @@
         PLLStatus = RCC->CR & RCC_CR_PLLRDY;
     } while((PLLStatus == 0) && (PLLStartUpCounter < PLL_STARTUP_TIMEOUT)); // wait for pll
     if(PLLStatus == 0) {
-        return(0);
+        return(PLL_ERR);
     }
     FLASH_SetLatency(FLASH_Latency_1);
     FLASH_PrefetchBufferCmd(ENABLE);
@@ -42,5 +53,5 @@
     RCC_HCLKConfig(RCC_SYSCLK_Div2);
     RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);  // switch to 32 MHz clock
     SystemCoreClockUpdate();                    // update SystemCoreClock var
-    return(1);
+    return(OK);
 }
\ No newline at end of file