Diff: ST_L152_32MHZ.cpp

Revision:

0:84e23a19e37d

Child:

1:bdeac50afe1a

--- /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);
+}
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