54c11ebd07
- McHCK uses FLL instead of the PLL for USB (startup, not usb init) - Added optional debug for the pjrc USB module - Cleaned up compiler flags
557 řádky
25 KiB
C
557 řádky
25 KiB
C
/* Teensyduino Core Library
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* http://www.pjrc.com/teensy/
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* Copyright (c) 2013 PJRC.COM, LLC.
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* Modifications by Jacob Alexander 2014
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* 1. The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* 2. If the Software is incorporated into a build system that allows
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* selection among a list of target devices, then similar target
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* devices manufactured by PJRC.COM must be included in the list of
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* target devices and selectable in the same manner.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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// Local Includes
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#include "mk20dx.h"
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#include <print.h>
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// ----- Variables -----
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extern unsigned long _stext;
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extern unsigned long _etext;
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extern unsigned long _sdata;
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extern unsigned long _edata;
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extern unsigned long _sbss;
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extern unsigned long _ebss;
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extern unsigned long _estack;
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// ----- Function Declarations -----
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extern int main ();
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void ResetHandler();
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// ----- Interrupts -----
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// NVIC - Default ISR
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void fault_isr()
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{
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while ( 1 )
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{
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// keep polling some communication while in fault
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// mode, so we don't completely die.
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if ( SIM_SCGC4 & SIM_SCGC4_USBOTG ) usb_isr();
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if ( SIM_SCGC4 & SIM_SCGC4_UART0 ) uart0_status_isr();
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if ( SIM_SCGC4 & SIM_SCGC4_UART1 ) uart1_status_isr();
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if ( SIM_SCGC4 & SIM_SCGC4_UART2 ) uart2_status_isr();
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}
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}
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void unused_isr()
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{
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fault_isr();
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}
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// NVIC - SysTick ISR
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extern volatile uint32_t systick_millis_count;
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void systick_default_isr()
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{
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systick_millis_count++;
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}
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// NVIC - Default ISR/Vector Linking
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void nmi_isr() __attribute__ ((weak, alias("unused_isr")));
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void hard_fault_isr() __attribute__ ((weak, alias("unused_isr")));
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void memmanage_fault_isr() __attribute__ ((weak, alias("unused_isr")));
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void bus_fault_isr() __attribute__ ((weak, alias("unused_isr")));
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void usage_fault_isr() __attribute__ ((weak, alias("unused_isr")));
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void svcall_isr() __attribute__ ((weak, alias("unused_isr")));
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void debugmonitor_isr() __attribute__ ((weak, alias("unused_isr")));
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void pendablesrvreq_isr() __attribute__ ((weak, alias("unused_isr")));
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void systick_isr() __attribute__ ((weak, alias("systick_default_isr")));
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void dma_ch0_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch1_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch2_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch3_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch4_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch5_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch6_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch7_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch8_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch9_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch10_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch11_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch12_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch13_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch14_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_ch15_isr() __attribute__ ((weak, alias("unused_isr")));
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void dma_error_isr() __attribute__ ((weak, alias("unused_isr")));
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void mcm_isr() __attribute__ ((weak, alias("unused_isr")));
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void flash_cmd_isr() __attribute__ ((weak, alias("unused_isr")));
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void flash_error_isr() __attribute__ ((weak, alias("unused_isr")));
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void low_voltage_isr() __attribute__ ((weak, alias("unused_isr")));
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void wakeup_isr() __attribute__ ((weak, alias("unused_isr")));
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void watchdog_isr() __attribute__ ((weak, alias("unused_isr")));
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void i2c0_isr() __attribute__ ((weak, alias("unused_isr")));
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void i2c1_isr() __attribute__ ((weak, alias("unused_isr")));
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void i2c2_isr() __attribute__ ((weak, alias("unused_isr")));
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void spi0_isr() __attribute__ ((weak, alias("unused_isr")));
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void spi1_isr() __attribute__ ((weak, alias("unused_isr")));
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void spi2_isr() __attribute__ ((weak, alias("unused_isr")));
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void sdhc_isr() __attribute__ ((weak, alias("unused_isr")));
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void can0_message_isr() __attribute__ ((weak, alias("unused_isr")));
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void can0_bus_off_isr() __attribute__ ((weak, alias("unused_isr")));
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void can0_error_isr() __attribute__ ((weak, alias("unused_isr")));
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void can0_tx_warn_isr() __attribute__ ((weak, alias("unused_isr")));
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void can0_rx_warn_isr() __attribute__ ((weak, alias("unused_isr")));
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void can0_wakeup_isr() __attribute__ ((weak, alias("unused_isr")));
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void i2s0_tx_isr() __attribute__ ((weak, alias("unused_isr")));
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void i2s0_rx_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart0_lon_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart0_status_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart0_error_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart1_status_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart1_error_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart2_status_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart2_error_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart3_status_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart3_error_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart4_status_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart4_error_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart5_status_isr() __attribute__ ((weak, alias("unused_isr")));
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void uart5_error_isr() __attribute__ ((weak, alias("unused_isr")));
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void adc0_isr() __attribute__ ((weak, alias("unused_isr")));
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void adc1_isr() __attribute__ ((weak, alias("unused_isr")));
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void cmp0_isr() __attribute__ ((weak, alias("unused_isr")));
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void cmp1_isr() __attribute__ ((weak, alias("unused_isr")));
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void cmp2_isr() __attribute__ ((weak, alias("unused_isr")));
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void ftm0_isr() __attribute__ ((weak, alias("unused_isr")));
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void ftm1_isr() __attribute__ ((weak, alias("unused_isr")));
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void ftm2_isr() __attribute__ ((weak, alias("unused_isr")));
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void ftm3_isr() __attribute__ ((weak, alias("unused_isr")));
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void cmt_isr() __attribute__ ((weak, alias("unused_isr")));
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void rtc_alarm_isr() __attribute__ ((weak, alias("unused_isr")));
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void rtc_seconds_isr() __attribute__ ((weak, alias("unused_isr")));
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void pit0_isr() __attribute__ ((weak, alias("unused_isr")));
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void pit1_isr() __attribute__ ((weak, alias("unused_isr")));
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void pit2_isr() __attribute__ ((weak, alias("unused_isr")));
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void pit3_isr() __attribute__ ((weak, alias("unused_isr")));
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void pdb_isr() __attribute__ ((weak, alias("unused_isr")));
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void usb_isr() __attribute__ ((weak, alias("unused_isr")));
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void usb_charge_isr() __attribute__ ((weak, alias("unused_isr")));
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void dac0_isr() __attribute__ ((weak, alias("unused_isr")));
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void dac1_isr() __attribute__ ((weak, alias("unused_isr")));
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void tsi0_isr() __attribute__ ((weak, alias("unused_isr")));
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void mcg_isr() __attribute__ ((weak, alias("unused_isr")));
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void lptmr_isr() __attribute__ ((weak, alias("unused_isr")));
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void porta_isr() __attribute__ ((weak, alias("unused_isr")));
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void portb_isr() __attribute__ ((weak, alias("unused_isr")));
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void portc_isr() __attribute__ ((weak, alias("unused_isr")));
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void portd_isr() __attribute__ ((weak, alias("unused_isr")));
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void porte_isr() __attribute__ ((weak, alias("unused_isr")));
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void software_isr() __attribute__ ((weak, alias("unused_isr")));
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// NVIC - Interrupt Vector Table
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__attribute__ ((section(".vectors"), used))
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void (* const gVectors[])() =
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{
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(void (*)(void))((unsigned long)&_estack), // 0 ARM: Initial Stack Pointer
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ResetHandler, // 1 ARM: Initial Program Counter
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nmi_isr, // 2 ARM: Non-maskable Interrupt (NMI)
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hard_fault_isr, // 3 ARM: Hard Fault
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memmanage_fault_isr, // 4 ARM: MemManage Fault
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bus_fault_isr, // 5 ARM: Bus Fault
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usage_fault_isr, // 6 ARM: Usage Fault
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fault_isr, // 7 --
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fault_isr, // 8 --
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fault_isr, // 9 --
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fault_isr, // 10 --
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svcall_isr, // 11 ARM: Supervisor call (SVCall)
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debugmonitor_isr, // 12 ARM: Debug Monitor
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fault_isr, // 13 --
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pendablesrvreq_isr, // 14 ARM: Pendable req serv(PendableSrvReq)
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systick_isr, // 15 ARM: System tick timer (SysTick)
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#if defined(_mk20dx128_) || defined(_mk20dx128vlf5_)
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dma_ch0_isr, // 16 DMA channel 0 transfer complete
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dma_ch1_isr, // 17 DMA channel 1 transfer complete
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dma_ch2_isr, // 18 DMA channel 2 transfer complete
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dma_ch3_isr, // 19 DMA channel 3 transfer complete
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dma_error_isr, // 20 DMA error interrupt channel
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unused_isr, // 21 DMA --
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flash_cmd_isr, // 22 Flash Memory Command complete
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flash_error_isr, // 23 Flash Read collision
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low_voltage_isr, // 24 Low-voltage detect/warning
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wakeup_isr, // 25 Low Leakage Wakeup
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watchdog_isr, // 26 Both EWM and WDOG interrupt
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i2c0_isr, // 27 I2C0
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spi0_isr, // 28 SPI0
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i2s0_tx_isr, // 29 I2S0 Transmit
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i2s0_rx_isr, // 30 I2S0 Receive
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uart0_lon_isr, // 31 UART0 CEA709.1-B (LON) status
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uart0_status_isr, // 32 UART0 status
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uart0_error_isr, // 33 UART0 error
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uart1_status_isr, // 34 UART1 status
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uart1_error_isr, // 35 UART1 error
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uart2_status_isr, // 36 UART2 status
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uart2_error_isr, // 37 UART2 error
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adc0_isr, // 38 ADC0
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cmp0_isr, // 39 CMP0
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cmp1_isr, // 40 CMP1
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ftm0_isr, // 41 FTM0
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ftm1_isr, // 42 FTM1
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cmt_isr, // 43 CMT
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rtc_alarm_isr, // 44 RTC Alarm interrupt
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rtc_seconds_isr, // 45 RTC Seconds interrupt
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pit0_isr, // 46 PIT Channel 0
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pit1_isr, // 47 PIT Channel 1
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pit2_isr, // 48 PIT Channel 2
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pit3_isr, // 49 PIT Channel 3
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pdb_isr, // 50 PDB Programmable Delay Block
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usb_isr, // 51 USB OTG
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usb_charge_isr, // 52 USB Charger Detect
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tsi0_isr, // 53 TSI0
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mcg_isr, // 54 MCG
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lptmr_isr, // 55 Low Power Timer
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porta_isr, // 56 Pin detect (Port A)
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portb_isr, // 57 Pin detect (Port B)
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portc_isr, // 58 Pin detect (Port C)
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portd_isr, // 59 Pin detect (Port D)
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porte_isr, // 60 Pin detect (Port E)
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software_isr, // 61 Software interrupt
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#elif defined(_mk20dx256_)
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dma_ch0_isr, // 16 DMA channel 0 transfer complete
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dma_ch1_isr, // 17 DMA channel 1 transfer complete
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dma_ch2_isr, // 18 DMA channel 2 transfer complete
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dma_ch3_isr, // 19 DMA channel 3 transfer complete
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dma_ch4_isr, // 20 DMA channel 4 transfer complete
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dma_ch5_isr, // 21 DMA channel 5 transfer complete
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dma_ch6_isr, // 22 DMA channel 6 transfer complete
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dma_ch7_isr, // 23 DMA channel 7 transfer complete
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dma_ch8_isr, // 24 DMA channel 8 transfer complete
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dma_ch9_isr, // 25 DMA channel 9 transfer complete
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dma_ch10_isr, // 26 DMA channel 10 transfer complete
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dma_ch11_isr, // 27 DMA channel 10 transfer complete
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dma_ch12_isr, // 28 DMA channel 10 transfer complete
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dma_ch13_isr, // 29 DMA channel 10 transfer complete
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dma_ch14_isr, // 30 DMA channel 10 transfer complete
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dma_ch15_isr, // 31 DMA channel 10 transfer complete
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dma_error_isr, // 32 DMA error interrupt channel
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unused_isr, // 33 --
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flash_cmd_isr, // 34 Flash Memory Command complete
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flash_error_isr, // 35 Flash Read collision
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low_voltage_isr, // 36 Low-voltage detect/warning
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wakeup_isr, // 37 Low Leakage Wakeup
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watchdog_isr, // 38 Both EWM and WDOG interrupt
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unused_isr, // 39 --
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i2c0_isr, // 40 I2C0
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i2c1_isr, // 41 I2C1
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spi0_isr, // 42 SPI0
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spi1_isr, // 43 SPI1
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unused_isr, // 44 --
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can0_message_isr, // 45 CAN OR'ed Message buffer (0-15)
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can0_bus_off_isr, // 46 CAN Bus Off
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can0_error_isr, // 47 CAN Error
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can0_tx_warn_isr, // 48 CAN Transmit Warning
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can0_rx_warn_isr, // 49 CAN Receive Warning
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can0_wakeup_isr, // 50 CAN Wake Up
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i2s0_tx_isr, // 51 I2S0 Transmit
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i2s0_rx_isr, // 52 I2S0 Receive
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unused_isr, // 53 --
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unused_isr, // 54 --
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unused_isr, // 55 --
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unused_isr, // 56 --
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unused_isr, // 57 --
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unused_isr, // 58 --
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unused_isr, // 59 --
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uart0_lon_isr, // 60 UART0 CEA709.1-B (LON) status
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uart0_status_isr, // 61 UART0 status
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uart0_error_isr, // 62 UART0 error
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uart1_status_isr, // 63 UART1 status
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uart1_error_isr, // 64 UART1 error
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uart2_status_isr, // 65 UART2 status
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uart2_error_isr, // 66 UART2 error
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unused_isr, // 67 --
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unused_isr, // 68 --
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unused_isr, // 69 --
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unused_isr, // 70 --
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unused_isr, // 71 --
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unused_isr, // 72 --
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adc0_isr, // 73 ADC0
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adc1_isr, // 74 ADC1
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cmp0_isr, // 75 CMP0
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cmp1_isr, // 76 CMP1
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cmp2_isr, // 77 CMP2
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ftm0_isr, // 78 FTM0
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ftm1_isr, // 79 FTM1
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ftm2_isr, // 80 FTM2
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cmt_isr, // 81 CMT
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rtc_alarm_isr, // 82 RTC Alarm interrupt
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rtc_seconds_isr, // 83 RTC Seconds interrupt
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pit0_isr, // 84 PIT Channel 0
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pit1_isr, // 85 PIT Channel 1
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pit2_isr, // 86 PIT Channel 2
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pit3_isr, // 87 PIT Channel 3
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pdb_isr, // 88 PDB Programmable Delay Block
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usb_isr, // 89 USB OTG
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usb_charge_isr, // 90 USB Charger Detect
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unused_isr, // 91 --
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unused_isr, // 92 --
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unused_isr, // 93 --
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unused_isr, // 94 --
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unused_isr, // 95 --
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unused_isr, // 96 --
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dac0_isr, // 97 DAC0
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unused_isr, // 98 --
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tsi0_isr, // 99 TSI0
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mcg_isr, // 100 MCG
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lptmr_isr, // 101 Low Power Timer
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unused_isr, // 102 --
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porta_isr, // 103 Pin detect (Port A)
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portb_isr, // 104 Pin detect (Port B)
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portc_isr, // 105 Pin detect (Port C)
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portd_isr, // 106 Pin detect (Port D)
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porte_isr, // 107 Pin detect (Port E)
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unused_isr, // 108 --
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unused_isr, // 109 --
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software_isr, // 110 Software interrupt
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#endif
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};
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// ----- Flash Configuration -----
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// Only necessary for Teensy 3s, MCHCK uses the Bootloader to handle this
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#if defined(_mk20dx128_) || defined(_mk20dx256_)
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__attribute__ ((section(".flashconfig"), used))
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const uint8_t flashconfigbytes[16] = {
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0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
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0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFF, 0xFF, 0xFF
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};
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#endif
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// ----- Chip Entry Point -----
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__attribute__ ((section(".startup")))
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void ResetHandler()
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{
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uint32_t *src = &_etext;
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uint32_t *dest = &_sdata;
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// Disable Watchdog
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WDOG_UNLOCK = WDOG_UNLOCK_SEQ1;
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WDOG_UNLOCK = WDOG_UNLOCK_SEQ2;
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WDOG_STCTRLH = WDOG_STCTRLH_ALLOWUPDATE;
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// Enable clocks to always-used peripherals
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SIM_SCGC5 = 0x00043F82; // Clocks active to all GPIO
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SIM_SCGC6 = SIM_SCGC6_FTM0 | SIM_SCGC6_FTM1 | SIM_SCGC6_ADC0 | SIM_SCGC6_FTFL;
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#if defined(_mk20dx128_)
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SIM_SCGC6 |= SIM_SCGC6_RTC;
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#elif defined(_mk20dx256_)
|
|
SIM_SCGC3 = SIM_SCGC3_ADC1 | SIM_SCGC3_FTM2;
|
|
SIM_SCGC6 |= SIM_SCGC6_RTC;
|
|
#endif
|
|
|
|
#if defined(_mk20dx128_) || defined(_mk20dx256_) // Teensy 3s
|
|
// if the RTC oscillator isn't enabled, get it started early
|
|
if ( !(RTC_CR & RTC_CR_OSCE) )
|
|
{
|
|
RTC_SR = 0;
|
|
RTC_CR = RTC_CR_SC16P | RTC_CR_SC4P | RTC_CR_OSCE;
|
|
}
|
|
#endif
|
|
|
|
// release I/O pins hold, if we woke up from VLLS mode
|
|
if ( PMC_REGSC & PMC_REGSC_ACKISO )
|
|
{
|
|
PMC_REGSC |= PMC_REGSC_ACKISO;
|
|
}
|
|
|
|
// Prepare RAM
|
|
while ( dest < &_edata ) *dest++ = *src++;
|
|
dest = &_sbss;
|
|
while ( dest < &_ebss ) *dest++ = 0;
|
|
|
|
// MCHCK
|
|
#if defined(_mk20dx128vlf5_)
|
|
// Default all interrupts to medium priority level
|
|
for ( unsigned int i = 0; i < NVIC_NUM_INTERRUPTS; i++ )
|
|
{
|
|
NVIC_SET_PRIORITY( i, 128 );
|
|
}
|
|
|
|
// FLL at 48MHz
|
|
MCG_C4 = MCG_C4_DMX32 | MCG_C4_DRST_DRS( 1 );
|
|
|
|
// USB Clock and FLL select
|
|
SIM_SOPT2 = SIM_SOPT2_USBSRC | SIM_SOPT2_TRACECLKSEL;
|
|
|
|
// Teensy 3.0 and 3.1
|
|
#else
|
|
unsigned int i;
|
|
|
|
SCB_VTOR = 0; // use vector table in flash
|
|
|
|
// default all interrupts to medium priority level
|
|
for ( i = 0; i < NVIC_NUM_INTERRUPTS; i++ )
|
|
{
|
|
NVIC_SET_PRIORITY( i, 128 );
|
|
}
|
|
|
|
// start in FEI mode
|
|
// enable capacitors for crystal
|
|
OSC0_CR = OSC_SC8P | OSC_SC2P;
|
|
|
|
// enable osc, 8-32 MHz range, low power mode
|
|
MCG_C2 = MCG_C2_RANGE0( 2 ) | MCG_C2_EREFS;
|
|
|
|
// switch to crystal as clock source, FLL input = 16 MHz / 512
|
|
MCG_C1 = MCG_C1_CLKS( 2 ) | MCG_C1_FRDIV( 4 );
|
|
|
|
// wait for crystal oscillator to begin
|
|
while ( (MCG_S & MCG_S_OSCINIT0) == 0 );
|
|
|
|
// wait for FLL to use oscillator
|
|
while ( (MCG_S & MCG_S_IREFST) != 0 );
|
|
|
|
// wait for MCGOUT to use oscillator
|
|
while ( (MCG_S & MCG_S_CLKST_MASK) != MCG_S_CLKST( 2 ) );
|
|
|
|
// now we're in FBE mode
|
|
// config PLL input for 16 MHz Crystal / 4 = 4 MHz
|
|
MCG_C5 = MCG_C5_PRDIV0( 3 );
|
|
|
|
// config PLL for 96 MHz output
|
|
MCG_C6 = MCG_C6_PLLS | MCG_C6_VDIV0( 0 );
|
|
|
|
// wait for PLL to start using xtal as its input
|
|
while ( !(MCG_S & MCG_S_PLLST) );
|
|
|
|
// wait for PLL to lock
|
|
while ( !(MCG_S & MCG_S_LOCK0) );
|
|
|
|
// now we're in PBE mode
|
|
#if F_CPU == 96000000
|
|
// config divisors: 96 MHz core, 48 MHz bus, 24 MHz flash
|
|
SIM_CLKDIV1 = SIM_CLKDIV1_OUTDIV1( 0 ) | SIM_CLKDIV1_OUTDIV2( 1 ) | SIM_CLKDIV1_OUTDIV4( 3 );
|
|
#elif F_CPU == 48000000
|
|
// config divisors: 48 MHz core, 48 MHz bus, 24 MHz flash
|
|
SIM_CLKDIV1 = SIM_CLKDIV1_OUTDIV1( 1 ) | SIM_CLKDIV1_OUTDIV2( 1 ) | SIM_CLKDIV1_OUTDIV4( 3 );
|
|
#elif F_CPU == 24000000
|
|
// config divisors: 24 MHz core, 24 MHz bus, 24 MHz flash
|
|
SIM_CLKDIV1 = SIM_CLKDIV1_OUTDIV1( 3 ) | SIM_CLKDIV1_OUTDIV2( 3 ) | SIM_CLKDIV1_OUTDIV4( 3 );
|
|
#else
|
|
#error "Error, F_CPU must be 96000000, 48000000, or 24000000"
|
|
#endif
|
|
// switch to PLL as clock source, FLL input = 16 MHz / 512
|
|
MCG_C1 = MCG_C1_CLKS( 0 ) | MCG_C1_FRDIV( 4 );
|
|
|
|
// wait for PLL clock to be used
|
|
while ( (MCG_S & MCG_S_CLKST_MASK) != MCG_S_CLKST( 3 ) );
|
|
|
|
// now we're in PEE mode
|
|
// configure USB for 48 MHz clock
|
|
SIM_CLKDIV2 = SIM_CLKDIV2_USBDIV( 1 ); // USB = 96 MHz PLL / 2
|
|
|
|
// USB uses PLL clock, trace is CPU clock, CLKOUT=OSCERCLK0
|
|
SIM_SOPT2 = SIM_SOPT2_USBSRC | SIM_SOPT2_PLLFLLSEL | SIM_SOPT2_TRACECLKSEL | SIM_SOPT2_CLKOUTSEL( 6 );
|
|
|
|
#endif
|
|
// Initialize the SysTick counter
|
|
SYST_RVR = (F_CPU / 1000) - 1;
|
|
SYST_CSR = SYST_CSR_CLKSOURCE | SYST_CSR_TICKINT | SYST_CSR_ENABLE;
|
|
|
|
__enable_irq();
|
|
|
|
main();
|
|
while ( 1 ); // Shouldn't get here...
|
|
}
|
|
|
|
|
|
|
|
// ----- RAM Setup -----
|
|
|
|
char *__brkval = (char *)&_ebss;
|
|
|
|
void * _sbrk( int incr )
|
|
{
|
|
char *prev = __brkval;
|
|
__brkval += incr;
|
|
return prev;
|
|
}
|
|
|
|
|
|
|
|
// ----- Interrupt Execution Priority -----
|
|
|
|
int nvic_execution_priority()
|
|
{
|
|
int priority = 256;
|
|
uint32_t primask, faultmask, basepri, ipsr;
|
|
|
|
// full algorithm in ARM DDI0403D, page B1-639
|
|
// this isn't quite complete, but hopefully good enough
|
|
asm volatile( "mrs %0, faultmask\n" : "=r" (faultmask):: );
|
|
if ( faultmask )
|
|
{
|
|
return -1;
|
|
}
|
|
|
|
asm volatile( "mrs %0, primask\n" : "=r" (primask):: );
|
|
if ( primask )
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
asm volatile( "mrs %0, ipsr\n" : "=r" (ipsr):: );
|
|
if ( ipsr )
|
|
{
|
|
if ( ipsr < 16)
|
|
{
|
|
priority = 0; // could be non-zero
|
|
}
|
|
else
|
|
{
|
|
priority = NVIC_GET_PRIORITY( ipsr - 16 );
|
|
}
|
|
}
|
|
|
|
asm volatile( "mrs %0, basepri\n" : "=r" (basepri):: );
|
|
if ( basepri > 0 && basepri < priority )
|
|
{
|
|
priority = basepri;
|
|
}
|
|
|
|
return priority;
|
|
}
|
|
|