K20 uVision files, ld NVIC offset

	- K20 KEIL files
	- clock set to 1 (48MHz)
	- offset in GCC ld for vectors in RAM
	- us ticker - PIT timer interrupt implementation

Author: 0xc0170

libraries/mbed/targets/cmsis/TARGET_Freescale/TARGET_K20D5M/TOOLCHAIN_ARM_STD/MK20D5.sct

@@ -0,0 +1,14 @@
+
+LR_IROM1 0x00000000 0x20000  {    ; load region size_region (132k)
+  ER_IROM1 0x00000000 0x20000  {  ; load address = execution address
+   *.o (RESET, +First)
+   *(InRoot$$Sections)
+   .ANY (+RO)
+  }
+  ; 8_byte_aligned(61 vect * 4 bytes) =  8_byte_aligned(0xF4) = 0xF8
+  ; 0x4000 - 0xF8 = 0x3F08
+  RW_IRAM1 0x1FFFE0F8 0x3F08 {
+   .ANY (+RW +ZI)
+  }
+}
+

libraries/mbed/targets/cmsis/TARGET_Freescale/TARGET_K20D5M/TOOLCHAIN_ARM_STD/startup_MK20D5.s

@@ -0,0 +1,31 @@
+/* mbed Microcontroller Library - stackheap
+ * Copyright (C) 2009-2011 ARM Limited. All rights reserved.
+ *
+ * Setup a fixed single stack/heap memory model,
+ *  between the top of the RW/ZI region and the stackpointer
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <rt_misc.h>
+#include <stdint.h>
+
+extern char Image$$RW_IRAM1$$ZI$$Limit[];
+
+extern __value_in_regs struct __initial_stackheap __user_setup_stackheap(uint32_t R0, uint32_t R1, uint32_t R2, uint32_t R3) {
+    uint32_t zi_limit = (uint32_t)Image$$RW_IRAM1$$ZI$$Limit;
+    uint32_t sp_limit = __current_sp();
+
+    zi_limit = (zi_limit + 7) & ~0x7;    // ensure zi_limit is 8-byte aligned
+
+    struct __initial_stackheap r;
+    r.heap_base = zi_limit;
+    r.heap_limit = sp_limit;
+    return r;
+}
+
+#ifdef __cplusplus
+}
+#endif

libraries/mbed/targets/cmsis/TARGET_Freescale/TARGET_K20D5M/TOOLCHAIN_ARM_STD/sys.cpp

@@ -1,13 +1,13 @@
 /*
- * KL25Z ARM GCC linker script file
+ * K20 ARM GCC linker script file
  */
 
 MEMORY
 {
   VECTORS (rx) : ORIGIN = 0x00000000, LENGTH = 0x00000400
   FLASH_PROTECTION	(rx) : ORIGIN = 0x00000400, LENGTH = 0x00000010
   FLASH (rx) : ORIGIN = 0x00000410, LENGTH = 128K - 0x00000410
-  RAM (rwx) : ORIGIN = 0x1FFFE000, LENGTH = 16K 
+  RAM (rwx) : ORIGIN = 0x1FFFE0F8, LENGTH = 16K - 0xC8
 }
 
 /* Linker script to place sections and symbol values. Should be used together

libraries/mbed/targets/cmsis/TARGET_Freescale/TARGET_K20D5M/TOOLCHAIN_GCC_ARM/MK20D5.ld

@@ -211,4 +211,15 @@ Reset_Handler:
     def_irq_handler    CPU_CLCD_IRQHandler
     def_irq_handler    SPI_IRQHandler
 
+/* Flash protection region, placed at 0x400 */
+    .text
+    .thumb
+    .align 2
+    .section .kinetis_flash_config_field,"a",%progbits
+kinetis_flash_config:
+    .long 0xffffffff
+    .long 0xffffffff
+    .long 0xffffffff
+    .long 0xfffffffe
+
     .end

libraries/mbed/targets/cmsis/TARGET_Freescale/TARGET_K20D5M/TOOLCHAIN_GCC_ARM/startup_MK20D5.s

@@ -44,7 +44,7 @@
 
 #define DISABLE_WDOG    1
 
-#define CLOCK_SETUP     0
+#define CLOCK_SETUP     1
 /* Predefined clock setups
    0 ... Multipurpose Clock Generator (MCG) in FLL Engaged Internal (FEI) mode
          Reference clock source for MCG module is the slow internal clock source 32.768kHz

libraries/mbed/targets/cmsis/TARGET_Freescale/TARGET_K20D5M/system_MK20D5.c

@@ -30,29 +30,34 @@ void us_ticker_init(void) {
     lptmr_init();
 }
 
+static uint32_t pit_us_ticker_counter = 0;
+
+void pit0_isr(void) {
+    pit_us_ticker_counter++;
+    PIT->CHANNEL[0].LDVAL = 48; // 1us
+    PIT->CHANNEL[0].TFLG = 1;
+}
+
 /******************************************************************************
  * Timer for us timing.
  ******************************************************************************/
 static void pit_init(void) {
-    SIM->SCGC6 |= SIM_SCGC6_PIT_MASK;   // Clock PIT
-    PIT->MCR = 0;                       // Enable PIT
-    
-    // Channel 1
-    PIT->CHANNEL[1].LDVAL = 0xFFFFFFFF;
-    PIT->CHANNEL[1].TCTRL = PIT_TCTRL_TIE_MASK;    // Chain to timer 0, disable Interrupts
-    PIT->CHANNEL[1].TCTRL |= PIT_TCTRL_TEN_MASK;   // Start timer 1
-    
-    // Use channel 0 as a prescaler for channel 1
-    PIT->CHANNEL[0].LDVAL = 23;
-    PIT->CHANNEL[0].TCTRL = PIT_TCTRL_TEN_MASK;    // Start timer 0, disable interrupts
+    SIM->SCGC6 |= SIM_SCGC6_PIT_MASK;  // Clock PIT
+    PIT->MCR = 0;  // Enable PIT
+
+    PIT->CHANNEL[0].LDVAL = 48;  // 1us
+    PIT->CHANNEL[0].TCTRL |= PIT_TCTRL_TIE_MASK;
+    PIT->CHANNEL[0].TCTRL |= PIT_TCTRL_TEN_MASK;  // Start timer 1
+
+    NVIC_SetVector(PIT0_IRQn, (uint32_t)pit0_isr);
+    NVIC_EnableIRQ(PIT0_IRQn);
 }
 
 uint32_t us_ticker_read() {
     if (!us_ticker_inited)
         us_ticker_init();
-    
-    // The PIT is a countdown timer
-    return ~(PIT->CHANNEL[1].CVAL);
+
+    return pit_us_ticker_counter;
 }
 
 /******************************************************************************

libraries/mbed/targets/hal/TARGET_Freescale/TARGET_K20D5M/us_ticker.c

@@ -140,7 +140,7 @@ def __init__(self):
 
         self.extra_labels = ['Freescale']
 
-        self.supported_toolchains = ["GCC_ARM"]
+        self.supported_toolchains = ["GCC_ARM", "ARM"]
 
         self.is_disk_virtual = True