Revision 587:61103edf8a92, committed 2015-07-10

Comitter:

mbed_official

Date:

Fri Jul 10 14:15:08 2015 +0100

Parent:

586:dfaf40375987

Child:

588:523654f2b367

Commit message:

Synchronized with git revision 6cb7294c83b739aaf94e7f5d477479c9e332c700

Full URL: https://github.com/mbedmicro/mbed/commit/6cb7294c83b739aaf94e7f5d477479c9e332c700/

[KL25Z] add 32KHz crystal clock setup 3 + minor RTC api changes

Changed in this revision

--- a/targets/cmsis/TARGET_Freescale/TARGET_KLXX/TARGET_KL25Z/system_MKL25Z4.c	Wed Jul 08 15:00:09 2015 +0100
+++ b/targets/cmsis/TARGET_Freescale/TARGET_KLXX/TARGET_KL25Z/system_MKL25Z4.c	Fri Jul 10 14:15:08 2015 +0100
@@ -55,6 +55,12 @@
    2 ... Multipurpose Clock Generator (MCG) in Bypassed Low Power External (BLPE) mode
          Core clock/Bus clock derived directly from an external crystal 8MHz with no multiplication
          Core clock = 8MHz, BusClock = 8MHz
+   3 ... Multipurpose Clock Generator (MCG) in FLL Engaged External (FEE) mode
+         Reference clock source for MCG module is an external crystal 32.768kHz
+         Core clock = 47.97MHz, BusClock = 23.98MHz
+         This setup sets the RTC to be driven by the MCU clock directly without the need of an external source.
+         RTC register values are retained when MCU is reset although there will be a slight (mSec's)loss of time
+         accuracy durring the reset period. RTC will reset on power down. 
 */
 
 /*----------------------------------------------------------------------------
@@ -75,8 +81,12 @@
     #define CPU_INT_SLOW_CLK_HZ             32768u   /* Value of the slow internal oscillator clock frequency in Hz  */
     #define CPU_INT_FAST_CLK_HZ             4000000u /* Value of the fast internal oscillator clock frequency in Hz  */
     #define DEFAULT_SYSTEM_CLOCK            8000000u /* Default System clock value */
-#endif /* (CLOCK_SETUP == 2) */
-
+#elif (CLOCK_SETUP == 3)    
+    #define CPU_XTAL_CLK_HZ                 32768u   /* Value of the external crystal or oscillator clock frequency in Hz */
+    #define CPU_INT_SLOW_CLK_HZ             32768u   /* Value of the slow internal oscillator clock frequency in Hz  */
+    #define CPU_INT_FAST_CLK_HZ             4000000u /* Value of the fast internal oscillator clock frequency in Hz  */
+    #define DEFAULT_SYSTEM_CLOCK            47972352u /* Default System clock value */       
+#endif /* (CLOCK_SETUP == 3) */
 
 /* ----------------------------------------------------------------------------
    -- Core clock
@@ -183,7 +193,34 @@
   MCG->C2 = (uint8_t)0x26U;
   while((MCG->S & 0x0CU) != 0x08U) {    /* Wait until external reference clock is selected as MCG output */
   }
-#endif /* (CLOCK_SETUP == 2) */
+#elif (CLOCK_SETUP == 3)  
+/* SIM->SCGC5: PORTA=1 */
+  SIM->SCGC5 |= SIM_SCGC5_PORTA_MASK;   /* Enable clock gate for ports to enable pin routing */
+  /* SIM->CLKDIV1: OUTDIV1=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,OUTDIV4=1,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0 */
+  SIM->CLKDIV1 = (SIM_CLKDIV1_OUTDIV1(0x00) | SIM_CLKDIV1_OUTDIV4(0x01)); /* Update system prescalers */
+  /* PORTA->PCR[3]: ISF=0,MUX=0 */
+  PORTA->PCR[3] &= (uint32_t)~(uint32_t)((PORT_PCR_ISF_MASK | PORT_PCR_MUX(0x07)));
+  /* PORTA->PCR[4]: ISF=0,MUX=0 */
+  PORTA->PCR[4] &= (uint32_t)~(uint32_t)((PORT_PCR_ISF_MASK | PORT_PCR_MUX(0x07)));
+  /* Switch to FEE Mode */
+  /* MCG->C2: LOCRE0=0,??=0,RANGE0=0,HGO0=0,EREFS0=1,LP=0,IRCS=0 */
+  MCG->C2 = (MCG_C2_RANGE0(0x00) | MCG_C2_EREFS0_MASK);
+  /* OSC0->CR: ERCLKEN=1,??=0,EREFSTEN=0,??=0,SC2P=0,SC4P=0,SC8P=0,SC16P=0 */
+  OSC0->CR = OSC_CR_ERCLKEN_MASK | OSC_CR_SC16P_MASK | OSC_CR_SC4P_MASK | OSC_CR_SC2P_MASK;
+  /* MCG->C1: CLKS=0,FRDIV=0,IREFS=0,IRCLKEN=1,IREFSTEN=0 */
+  MCG->C1 = (MCG_C1_CLKS(0x00) | MCG_C1_FRDIV(0x00) | MCG_C1_IRCLKEN_MASK);
+  /* MCG->C4: DMX32=1,DRST_DRS=1 */
+  MCG->C4 = (uint8_t)((MCG->C4 & (uint8_t)~(uint8_t)(
+            MCG_C4_DRST_DRS(0x02)
+           )) | (uint8_t)(
+            MCG_C4_DMX32_MASK |
+            MCG_C4_DRST_DRS(0x01)
+           ));
+  while((MCG->S & MCG_S_IREFST_MASK) != 0x00U) { /* Check that the source of the FLL reference clock is the external reference clock. */
+  }
+  while((MCG->S & 0x0CU) != 0x00U) {    /* Wait until output of the FLL is selected */
+  }          
+#endif /* (CLOCK_SETUP == 3) */
 }
 
 /* ----------------------------------------------------------------------------

--- a/targets/hal/TARGET_Freescale/TARGET_KLXX/rtc_api.c	Wed Jul 08 15:00:09 2015 +0100
+++ b/targets/hal/TARGET_Freescale/TARGET_KLXX/rtc_api.c	Fri Jul 10 14:15:08 2015 +0100
@@ -15,16 +15,24 @@
  */
 #include "rtc_api.h"
 #include "PeripheralPins.h"
+#include "clk_freqs.h"
 
 static void init(void) {
     // enable RTC clock
     SIM->SCGC6 |= SIM_SCGC6_RTC_MASK;
 
-    pinmap_pinout(PinMap_RTC[0].pin, PinMap_RTC);        //Map RTC clk input (if not NC)
-
     // select RTC clock source
     SIM->SOPT1 &= ~SIM_SOPT1_OSC32KSEL_MASK;
-    SIM->SOPT1 |= SIM_SOPT1_OSC32KSEL(PinMap_RTC[0].peripheral);
+    
+    // Enable external crystal source if clock source is 32KHz
+    if (extosc_frequency()==32768) {
+        SIM->SOPT1 |= SIM_SOPT1_OSC32KSEL(OSC32KCLK);
+    }
+    else{
+        // If main clock is NOT 32KHz crystal, use external 32KHz clock source defined in PeripheralPins.c
+        SIM->SOPT1 |= SIM_SOPT1_OSC32KSEL(PinMap_RTC[0].peripheral);
+        pinmap_pinout(PinMap_RTC[0].pin, PinMap_RTC);        //Map RTC clk input (if not NC)
+    }
 }
 
 void rtc_init(void) {