Viable NXP/Teensy support

- Fix UART & putChar
- Timer-based sleep
- Enable systick in abort
- Buffered, interrupt-based UART TX
- Use the new interrupt API and fix sleepTicks
- Make pins behave more like other boards
- Use the MCU's UART numbering
- Allow interrupts to wake the scheduler (#1214)

targets/nxpmk66f18.ld

@@ -5,8 +5,8 @@ ENTRY(Reset_Handler)
 /* define memory layout */
 MEMORY
 {
-	FLASH_TEXT (rx) : ORIGIN = 0x00000000, LENGTH = 1024K
-	RAM (rwx)       : ORIGIN = 0x1FFF0000, LENGTH = 256K
+    FLASH_TEXT (rx) : ORIGIN = 0x00000000, LENGTH = 1024K
+    RAM (rwx)       : ORIGIN = 0x1FFF0000, LENGTH = 256K
 }
 
 _stack_size = 2K;
@@ -18,21 +18,18 @@ SECTIONS
     .text :
     {
         /* vector table MUST start at 0x0 */
-		. = 0;
-        _vector_table = .;
+        . = 0;
         KEEP(*(.isr_vector))
 
         /* flash configuration MUST be at 0x400 */
         . = 0x400;
-        _flash_config = .;
-		KEEP(*(.flash_config))
+        KEEP(*(.flash_config))
 
         /* everything else */
-        *(.resetHandler)
         *(.text)
-        *(.text*)
+        *(.text.*)
         *(.rodata)
-        *(.rodata*)
+        *(.rodata.*)
         . = ALIGN(4);
 
     } >FLASH_TEXT = 0xFF
@@ -50,7 +47,7 @@ SECTIONS
     /* Start address (in flash) of .data, used by startup code. */
     _sidata = LOADADDR(.data);
 
-	/* todo add .usbdescriptortable .dmabuffers .usbbuffers */
+    /* this is where Teensy's LD script places .usbdescriptortable .dmabuffers .usbbuffers */
 
     /* Globals with initial value */
     .data :
@@ -58,7 +55,7 @@ SECTIONS
         . = ALIGN(4);
         _sdata = .;        /* used by startup code */
         *(.data)
-        *(.data*)
+        *(.data.*)
         . = ALIGN(4);
         _edata = .;        /* used by startup code */
     } >RAM AT>FLASH_TEXT
@@ -69,7 +66,7 @@ SECTIONS
         . = ALIGN(4);
         _sbss = .;         /* used by startup code */
         *(.bss)
-        *(.bss*)
+        *(.bss.*)
         *(COMMON)
         . = ALIGN(4);
         _ebss = .;         /* used by startup code */
@@ -79,11 +76,6 @@ SECTIONS
     {
         *(.ARM.exidx)      /* causes 'no memory region specified' error in lld */
         *(.ARM.exidx.*)    /* causes spurious 'undefined reference' errors */
-
-        /* all this makes it much harder to debug via disassembly */
-        *(.debug*)
-        *(.ARM.*)
-        *(.comment*)
     }
 }
 

targets/teensy36.s

@@ -1,7 +1,8 @@
-
 .section .flash_config
 .global  __flash_config
-	.byte 0xFF
+__flash_config:
+    .byte 0xFF
+    .byte 0xFF
     .byte 0xFF
     .byte 0xFF
     .byte 0xFF
@@ -9,11 +10,10 @@
     .byte 0xFF
     .byte 0xFF
     .byte 0xFF
-	.byte 0xFF
     .byte 0xFF
     .byte 0xFF
     .byte 0xFF
     .byte 0xDE
     .byte 0xF9
     .byte 0xFF
-    .byte 0xFF
+    .byte 0xFF