Revision 0:84e23a19e37d, committed 2014-03-11

Comitter:

dreschpe

Date:

Tue Mar 11 20:34:57 2014 +0000

Child:

1:bdeac50afe1a

Commit message:

Lib for the ST Nucleo L152RE board to switch the clock to 32MHz.; Out of the box the board is running on 16MHz.

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ST_L152_32MHZ.cpp	Tue Mar 11 20:34:57 2014 +0000
@@ -0,0 +1,46 @@
+
+
+#include "stm32l1xx.h"
+#include "stm32l1xx_flash.h"
+#include "stm32l1xx_rcc.h"
+#include "ST_L152_32MHZ.h"
+
+// set cpu clock to 32MHz
+
+
+
+L152_init32::L152_init32(unsigned int external){
+    clk_err = setup_clock_32MHZ(external);
+    }
+
+#define PLL_STARTUP_TIMEOUT 0x5000
+
+int L152_init32::setup_clock_32MHZ(int external)
+{
+    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.
+        error = RCC_WaitForHSEStartUp();
+        if(error == ERROR ) { // no external crystal
+            return(0);
+        }
+        RCC_PLLConfig(RCC_PLLSource_HSE,RCC_PLLMul_12,RCC_PLLDiv_3);   // setup pll to 96MHz to use USB
+    }
+    RCC_PLLCmd(ENABLE);                                                // switch on pll
+    do {
+        PLLStatus = RCC->CR & RCC_CR_PLLRDY;
+    } while((PLLStatus == 0) && (PLLStartUpCounter < PLL_STARTUP_TIMEOUT)); // wait for pll
+    if(PLLStatus == 0) {
+        return(0);
+    }
+    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
+    SystemCoreClockUpdate();                    // update SystemCoreClock var
+    return(1);
+}
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ST_L152_32MHZ.h	Tue Mar 11 20:34:57 2014 +0000
@@ -0,0 +1,49 @@
+/* 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.
+ */
+ 
+ 
+#ifndef MBED_ST_L152_32MHZ_H
+#define MBED_ST_L152_32MHZ_H
+
+/** Setup cpu speed to 32 MHz
+ *
+ * @code
+ * #include "mbed.h"
+ * #include "ST_L152_32MHZ.h"
+ *
+ * // place the init before other code to ensure right timing of other objects !
+ * L152_init32 myinit(0);   // use the internal oscillator 
+ * 
+ */
+
+class L152_init32
+{
+public:
+ /** Create a L152_init32 object to change the clock
+   * @param external = 0 use internal oscillator
+   * @param external = 1 use external 8 MHz crystal - you have to add some comonents to the pcb !
+*/
+L152_init32(unsigned int external);
+int clk_err;
+
+protected:
+// do the magic ;-)
+int setup_clock_32MHZ(int external);
+};
+
+#endif
+
+