Diff: targets/TARGET_Freescale/TARGET_K20XX/clk_freqs.h

Revision:

0:f269e3021894

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_Freescale/TARGET_K20XX/clk_freqs.h	Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,115 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2015 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef CLK_FREQS_H
+#define CLK_FREQS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*!
+ * \brief Get the peripheral bus clock frequency
+ * \return Bus frequency
+ */
+static inline uint32_t bus_frequency(void) {
+    return SystemCoreClock / (((SIM->CLKDIV1 & SIM_CLKDIV1_OUTDIV2_MASK) >> SIM_CLKDIV1_OUTDIV2_SHIFT) + 1);
+}
+
+/*!
+ * \brief Get external oscillator (crystal) frequency
+ * \return External osc frequency
+ */
+static uint32_t extosc_frequency(void) {
+    uint32_t MCGClock = SystemCoreClock * (1u + ((SIM->CLKDIV1 & SIM_CLKDIV1_OUTDIV1_MASK) >> SIM_CLKDIV1_OUTDIV1_SHIFT));
+
+    if ((MCG->C1 & MCG_C1_CLKS_MASK) == MCG_C1_CLKS(2))     //MCG clock = external reference clock
+        return MCGClock;
+
+    if ((MCG->C1 & MCG_C1_CLKS_MASK) == MCG_C1_CLKS(0)) {   //PLL/FLL is selected
+        uint32_t divider, multiplier;
+        if ((MCG->C6 & MCG_C6_PLLS_MASK) == 0x0u) {         //FLL is selected
+            if ((MCG->S & MCG_S_IREFST_MASK) == 0x0u) {     //FLL uses external reference
+                divider = (uint8_t)(1u << ((MCG->C1 & MCG_C1_FRDIV_MASK) >> MCG_C1_FRDIV_SHIFT));
+                if ((MCG->C2 & MCG_C2_RANGE0_MASK) != 0x0u)
+                    divider <<= 5u;
+                /* Select correct multiplier to calculate the MCG output clock  */
+                switch (MCG->C4 & (MCG_C4_DMX32_MASK | MCG_C4_DRST_DRS_MASK)) {
+                    case 0x0u:
+                      multiplier = 640u;
+                      break;
+                    case 0x20u:
+                      multiplier = 1280u;
+                      break;
+                    case 0x40u:
+                      multiplier = 1920u;
+                      break;
+                    case 0x60u:
+                      multiplier = 2560u;
+                      break;
+                    case 0x80u:
+                      multiplier = 732u;
+                      break;
+                    case 0xA0u:
+                      multiplier = 1464u;
+                      break;
+                    case 0xC0u:
+                      multiplier = 2197u;
+                      break;
+                    case 0xE0u:
+                    default:
+                      multiplier = 2929u;
+                      break;
+                }
+
+                return MCGClock * divider / multiplier;
+            }
+        } else {             //PLL is selected
+            divider = (1u + (MCG->C5 & MCG_C5_PRDIV0_MASK));
+            multiplier = ((MCG->C6 & MCG_C6_VDIV0_MASK) + 24u);
+            return MCGClock * divider / multiplier;
+        }
+    }
+
+    //In all other cases either there is no crystal or we cannot determine it
+    //For example when the FLL is running on the internal reference, and there is also an
+    //external crystal. However these are unlikely situations
+    return 0;
+}
+
+//Get MCG PLL/2 or FLL frequency, depending on which one is active, sets PLLFLLSEL bit
+static uint32_t mcgpllfll_frequency(void) { 
+    if ((MCG->C1 & MCG_C1_CLKS_MASK) != MCG_C1_CLKS(0))   //PLL/FLL is not selected
+        return 0;
+    
+    uint32_t MCGClock = SystemCoreClock * (1u + ((SIM->CLKDIV1 & SIM_CLKDIV1_OUTDIV1_MASK) >> SIM_CLKDIV1_OUTDIV1_SHIFT));
+    if ((MCG->C6 & MCG_C6_PLLS_MASK) == 0x0u) {         //FLL is selected
+        SIM->SOPT2 &= ~SIM_SOPT2_PLLFLLSEL_MASK;        //MCG peripheral clock is FLL output
+        return MCGClock;
+    } else {                                            //PLL is selected
+        SIM->SOPT2 |= SIM_SOPT2_PLLFLLSEL_MASK;         //MCG peripheral clock is PLL output
+        return MCGClock;
+    }
+    
+    //It is possible the SystemCoreClock isn't running on the PLL, and the PLL is still active 
+    //for the peripherals, this is however an unlikely setup
+}
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif