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controller/Lib/mk20dx.c

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/* Teensyduino Core Library
* http://www.pjrc.com/teensy/
* Copyright (c) 2013 PJRC.COM, LLC.
* Modifications by Jacob Alexander 2014-2015
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* 1. The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* 2. If the Software is incorporated into a build system that allows
* selection among a list of target devices, then similar target
* devices manufactured by PJRC.COM must be included in the list of
* target devices and selectable in the same manner.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
// ----- Includes -----
// Local Includes
#include "mk20dx.h"
// ----- Variables -----
extern unsigned long _stext;
extern unsigned long _etext;
extern unsigned long _sdata;
extern unsigned long _edata;
extern unsigned long _sbss;
extern unsigned long _ebss;
extern unsigned long _estack;
const uint8_t sys_reset_to_loader_magic[22] = "\xff\x00\x7fRESET TO LOADER\x7f\x00\xff";
// ----- Function Declarations -----
extern int main();
void ResetHandler();
// ----- Interrupts -----
// NVIC - Default ISR
void fault_isr()
{
while ( 1 )
{
// keep polling some communication while in fault
// mode, so we don't completely die.
if ( SIM_SCGC4 & SIM_SCGC4_USBOTG ) usb_isr();
if ( SIM_SCGC4 & SIM_SCGC4_UART0 ) uart0_status_isr();
if ( SIM_SCGC4 & SIM_SCGC4_UART1 ) uart1_status_isr();
if ( SIM_SCGC4 & SIM_SCGC4_UART2 ) uart2_status_isr();
}
}
void unused_isr()
{
fault_isr();
}
// NVIC - SysTick ISR
extern volatile uint32_t systick_millis_count;
void systick_default_isr()
{
systick_millis_count++;
}
// NVIC - Default ISR/Vector Linking
void nmi_isr() __attribute__ ((weak, alias("unused_isr")));
void hard_fault_isr() __attribute__ ((weak, alias("unused_isr")));
void memmanage_fault_isr() __attribute__ ((weak, alias("unused_isr")));
void bus_fault_isr() __attribute__ ((weak, alias("unused_isr")));
void usage_fault_isr() __attribute__ ((weak, alias("unused_isr")));
void svcall_isr() __attribute__ ((weak, alias("unused_isr")));
void debugmonitor_isr() __attribute__ ((weak, alias("unused_isr")));
void pendablesrvreq_isr() __attribute__ ((weak, alias("unused_isr")));
void systick_isr() __attribute__ ((weak, alias("systick_default_isr")));
void dma_ch0_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch1_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch2_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch3_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch4_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch5_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch6_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch7_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch8_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch9_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch10_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch11_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch12_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch13_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch14_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_ch15_isr() __attribute__ ((weak, alias("unused_isr")));
void dma_error_isr() __attribute__ ((weak, alias("unused_isr")));
void mcm_isr() __attribute__ ((weak, alias("unused_isr")));
void flash_cmd_isr() __attribute__ ((weak, alias("unused_isr")));
void flash_error_isr() __attribute__ ((weak, alias("unused_isr")));
void low_voltage_isr() __attribute__ ((weak, alias("unused_isr")));
void wakeup_isr() __attribute__ ((weak, alias("unused_isr")));
void watchdog_isr() __attribute__ ((weak, alias("unused_isr")));
void i2c0_isr() __attribute__ ((weak, alias("unused_isr")));
void i2c1_isr() __attribute__ ((weak, alias("unused_isr")));
void i2c2_isr() __attribute__ ((weak, alias("unused_isr")));
void spi0_isr() __attribute__ ((weak, alias("unused_isr")));
void spi1_isr() __attribute__ ((weak, alias("unused_isr")));
void spi2_isr() __attribute__ ((weak, alias("unused_isr")));
void sdhc_isr() __attribute__ ((weak, alias("unused_isr")));
void can0_message_isr() __attribute__ ((weak, alias("unused_isr")));
void can0_bus_off_isr() __attribute__ ((weak, alias("unused_isr")));
void can0_error_isr() __attribute__ ((weak, alias("unused_isr")));
void can0_tx_warn_isr() __attribute__ ((weak, alias("unused_isr")));
void can0_rx_warn_isr() __attribute__ ((weak, alias("unused_isr")));
void can0_wakeup_isr() __attribute__ ((weak, alias("unused_isr")));
void i2s0_tx_isr() __attribute__ ((weak, alias("unused_isr")));
void i2s0_rx_isr() __attribute__ ((weak, alias("unused_isr")));
void uart0_lon_isr() __attribute__ ((weak, alias("unused_isr")));
void uart0_status_isr() __attribute__ ((weak, alias("unused_isr")));
void uart0_error_isr() __attribute__ ((weak, alias("unused_isr")));
void uart1_status_isr() __attribute__ ((weak, alias("unused_isr")));
void uart1_error_isr() __attribute__ ((weak, alias("unused_isr")));
void uart2_status_isr() __attribute__ ((weak, alias("unused_isr")));
void uart2_error_isr() __attribute__ ((weak, alias("unused_isr")));
void uart3_status_isr() __attribute__ ((weak, alias("unused_isr")));
void uart3_error_isr() __attribute__ ((weak, alias("unused_isr")));
void uart4_status_isr() __attribute__ ((weak, alias("unused_isr")));
void uart4_error_isr() __attribute__ ((weak, alias("unused_isr")));
void uart5_status_isr() __attribute__ ((weak, alias("unused_isr")));
void uart5_error_isr() __attribute__ ((weak, alias("unused_isr")));
void adc0_isr() __attribute__ ((weak, alias("unused_isr")));
void adc1_isr() __attribute__ ((weak, alias("unused_isr")));
void cmp0_isr() __attribute__ ((weak, alias("unused_isr")));
void cmp1_isr() __attribute__ ((weak, alias("unused_isr")));
void cmp2_isr() __attribute__ ((weak, alias("unused_isr")));
void ftm0_isr() __attribute__ ((weak, alias("unused_isr")));
void ftm1_isr() __attribute__ ((weak, alias("unused_isr")));
void ftm2_isr() __attribute__ ((weak, alias("unused_isr")));
void ftm3_isr() __attribute__ ((weak, alias("unused_isr")));
void cmt_isr() __attribute__ ((weak, alias("unused_isr")));
void rtc_alarm_isr() __attribute__ ((weak, alias("unused_isr")));
void rtc_seconds_isr() __attribute__ ((weak, alias("unused_isr")));
void pit0_isr() __attribute__ ((weak, alias("unused_isr")));
void pit1_isr() __attribute__ ((weak, alias("unused_isr")));
void pit2_isr() __attribute__ ((weak, alias("unused_isr")));
void pit3_isr() __attribute__ ((weak, alias("unused_isr")));
void pdb_isr() __attribute__ ((weak, alias("unused_isr")));
void usb_isr() __attribute__ ((weak, alias("unused_isr")));
void usb_charge_isr() __attribute__ ((weak, alias("unused_isr")));
void dac0_isr() __attribute__ ((weak, alias("unused_isr")));
void dac1_isr() __attribute__ ((weak, alias("unused_isr")));
void tsi0_isr() __attribute__ ((weak, alias("unused_isr")));
void mcg_isr() __attribute__ ((weak, alias("unused_isr")));
void lptmr_isr() __attribute__ ((weak, alias("unused_isr")));
void porta_isr() __attribute__ ((weak, alias("unused_isr")));
void portb_isr() __attribute__ ((weak, alias("unused_isr")));
void portc_isr() __attribute__ ((weak, alias("unused_isr")));
void portd_isr() __attribute__ ((weak, alias("unused_isr")));
void porte_isr() __attribute__ ((weak, alias("unused_isr")));
void software_isr() __attribute__ ((weak, alias("unused_isr")));
// NVIC - Interrupt Vector Table
__attribute__ ((section(".vectors"), used))
void (* const gVectors[])() =
{
(void (*)(void))((unsigned long)&_estack), // 0 ARM: Initial Stack Pointer
ResetHandler, // 1 ARM: Initial Program Counter
nmi_isr, // 2 ARM: Non-maskable Interrupt (NMI)
hard_fault_isr, // 3 ARM: Hard Fault
memmanage_fault_isr, // 4 ARM: MemManage Fault
bus_fault_isr, // 5 ARM: Bus Fault
usage_fault_isr, // 6 ARM: Usage Fault
fault_isr, // 7 --
fault_isr, // 8 --
fault_isr, // 9 --
fault_isr, // 10 --
svcall_isr, // 11 ARM: Supervisor call (SVCall)
debugmonitor_isr, // 12 ARM: Debug Monitor
fault_isr, // 13 --
pendablesrvreq_isr, // 14 ARM: Pendable req serv(PendableSrvReq)
systick_isr, // 15 ARM: System tick timer (SysTick)
#if defined(_mk20dx128_) || defined(_mk20dx128vlf5_)
dma_ch0_isr, // 16 DMA channel 0 transfer complete
dma_ch1_isr, // 17 DMA channel 1 transfer complete
dma_ch2_isr, // 18 DMA channel 2 transfer complete
dma_ch3_isr, // 19 DMA channel 3 transfer complete
dma_error_isr, // 20 DMA error interrupt channel
unused_isr, // 21 DMA --
flash_cmd_isr, // 22 Flash Memory Command complete
flash_error_isr, // 23 Flash Read collision
low_voltage_isr, // 24 Low-voltage detect/warning
wakeup_isr, // 25 Low Leakage Wakeup
watchdog_isr, // 26 Both EWM and WDOG interrupt
i2c0_isr, // 27 I2C0
spi0_isr, // 28 SPI0
i2s0_tx_isr, // 29 I2S0 Transmit
i2s0_rx_isr, // 30 I2S0 Receive
uart0_lon_isr, // 31 UART0 CEA709.1-B (LON) status
uart0_status_isr, // 32 UART0 status
uart0_error_isr, // 33 UART0 error
uart1_status_isr, // 34 UART1 status
uart1_error_isr, // 35 UART1 error
uart2_status_isr, // 36 UART2 status
uart2_error_isr, // 37 UART2 error
adc0_isr, // 38 ADC0
cmp0_isr, // 39 CMP0
cmp1_isr, // 40 CMP1
ftm0_isr, // 41 FTM0
ftm1_isr, // 42 FTM1
cmt_isr, // 43 CMT
rtc_alarm_isr, // 44 RTC Alarm interrupt
rtc_seconds_isr, // 45 RTC Seconds interrupt
pit0_isr, // 46 PIT Channel 0
pit1_isr, // 47 PIT Channel 1
pit2_isr, // 48 PIT Channel 2
pit3_isr, // 49 PIT Channel 3
pdb_isr, // 50 PDB Programmable Delay Block
usb_isr, // 51 USB OTG
usb_charge_isr, // 52 USB Charger Detect
tsi0_isr, // 53 TSI0
mcg_isr, // 54 MCG
lptmr_isr, // 55 Low Power Timer
porta_isr, // 56 Pin detect (Port A)
portb_isr, // 57 Pin detect (Port B)
portc_isr, // 58 Pin detect (Port C)
portd_isr, // 59 Pin detect (Port D)
porte_isr, // 60 Pin detect (Port E)
software_isr, // 61 Software interrupt
#elif defined(_mk20dx256_) || defined(_mk20dx256vlh7_)
dma_ch0_isr, // 16 DMA channel 0 transfer complete
dma_ch1_isr, // 17 DMA channel 1 transfer complete
dma_ch2_isr, // 18 DMA channel 2 transfer complete
dma_ch3_isr, // 19 DMA channel 3 transfer complete
dma_ch4_isr, // 20 DMA channel 4 transfer complete
dma_ch5_isr, // 21 DMA channel 5 transfer complete
dma_ch6_isr, // 22 DMA channel 6 transfer complete
dma_ch7_isr, // 23 DMA channel 7 transfer complete
dma_ch8_isr, // 24 DMA channel 8 transfer complete
dma_ch9_isr, // 25 DMA channel 9 transfer complete
dma_ch10_isr, // 26 DMA channel 10 transfer complete
dma_ch11_isr, // 27 DMA channel 10 transfer complete
dma_ch12_isr, // 28 DMA channel 10 transfer complete
dma_ch13_isr, // 29 DMA channel 10 transfer complete
dma_ch14_isr, // 30 DMA channel 10 transfer complete
dma_ch15_isr, // 31 DMA channel 10 transfer complete
dma_error_isr, // 32 DMA error interrupt channel
unused_isr, // 33 --
flash_cmd_isr, // 34 Flash Memory Command complete
flash_error_isr, // 35 Flash Read collision
low_voltage_isr, // 36 Low-voltage detect/warning
wakeup_isr, // 37 Low Leakage Wakeup
watchdog_isr, // 38 Both EWM and WDOG interrupt
unused_isr, // 39 --
i2c0_isr, // 40 I2C0
i2c1_isr, // 41 I2C1
spi0_isr, // 42 SPI0
spi1_isr, // 43 SPI1
unused_isr, // 44 --
can0_message_isr, // 45 CAN OR'ed Message buffer (0-15)
can0_bus_off_isr, // 46 CAN Bus Off
can0_error_isr, // 47 CAN Error
can0_tx_warn_isr, // 48 CAN Transmit Warning
can0_rx_warn_isr, // 49 CAN Receive Warning
can0_wakeup_isr, // 50 CAN Wake Up
i2s0_tx_isr, // 51 I2S0 Transmit
i2s0_rx_isr, // 52 I2S0 Receive
unused_isr, // 53 --
unused_isr, // 54 --
unused_isr, // 55 --
unused_isr, // 56 --
unused_isr, // 57 --
unused_isr, // 58 --
unused_isr, // 59 --
uart0_lon_isr, // 60 UART0 CEA709.1-B (LON) status
uart0_status_isr, // 61 UART0 status
uart0_error_isr, // 62 UART0 error
uart1_status_isr, // 63 UART1 status
uart1_error_isr, // 64 UART1 error
uart2_status_isr, // 65 UART2 status
uart2_error_isr, // 66 UART2 error
unused_isr, // 67 --
unused_isr, // 68 --
unused_isr, // 69 --
unused_isr, // 70 --
unused_isr, // 71 --
unused_isr, // 72 --
adc0_isr, // 73 ADC0
adc1_isr, // 74 ADC1
cmp0_isr, // 75 CMP0
cmp1_isr, // 76 CMP1
cmp2_isr, // 77 CMP2
ftm0_isr, // 78 FTM0
ftm1_isr, // 79 FTM1
ftm2_isr, // 80 FTM2
cmt_isr, // 81 CMT
rtc_alarm_isr, // 82 RTC Alarm interrupt
rtc_seconds_isr, // 83 RTC Seconds interrupt
pit0_isr, // 84 PIT Channel 0
pit1_isr, // 85 PIT Channel 1
pit2_isr, // 86 PIT Channel 2
pit3_isr, // 87 PIT Channel 3
pdb_isr, // 88 PDB Programmable Delay Block
usb_isr, // 89 USB OTG
usb_charge_isr, // 90 USB Charger Detect
unused_isr, // 91 --
unused_isr, // 92 --
unused_isr, // 93 --
unused_isr, // 94 --
unused_isr, // 95 --
unused_isr, // 96 --
dac0_isr, // 97 DAC0
unused_isr, // 98 --
tsi0_isr, // 99 TSI0
mcg_isr, // 100 MCG
lptmr_isr, // 101 Low Power Timer
unused_isr, // 102 --
porta_isr, // 103 Pin detect (Port A)
portb_isr, // 104 Pin detect (Port B)
portc_isr, // 105 Pin detect (Port C)
portd_isr, // 106 Pin detect (Port D)
porte_isr, // 107 Pin detect (Port E)
unused_isr, // 108 --
unused_isr, // 109 --
software_isr, // 110 Software interrupt
#endif
};
// ----- Flash Configuration -----
// Only necessary for Teensy 3s, MCHCK uses the Bootloader to handle this
#if defined(_mk20dx128_) || defined(_mk20dx256_)
__attribute__ ((section(".flashconfig"), used))
const uint8_t flashconfigbytes[16] = {
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFF, 0xFF, 0xFF
};
#elif defined(_mk20dx128vlf5_) && defined(_bootloader_)
// XXX Byte labels may be in incorrect positions, double check before modifying
// FSEC is in correct location -Jacob
__attribute__ ((section(".flashconfig"), used))
const uint8_t flashconfigbytes[16] = {
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, // Backdoor Verif Key 28.3.1
//
// Protecting the first 4k of Flash memory from being over-written while running (bootloader protection)
// Still possible to overwrite the bootloader using an external flashing device
// For more details see:
// http://cache.freescale.com/files/training/doc/dwf/AMF_ENT_T1031_Boston.pdf (page 8)
// http://cache.freescale.com/files/microcontrollers/doc/app_note/AN4507.pdf
// http://cache.freescale.com/files/32bit/doc/ref_manual/K20P48M50SF0RM.pdf (28.34.6)
//
0xFF, 0xFF, 0xFF, 0xFE, // Program Flash Protection Bytes FPROT0-3
0xBE, // Flash security byte FSEC
0x03, // Flash nonvolatile option byte FOPT
0xFF, // EEPROM Protection Byte FEPROT
0xFF, // Data Flash Protection Byte FDPROT
};
#elif defined(_mk20dx256vlh7_) && defined(_bootloader_)
// XXX Byte labels may be in incorrect positions, double check before modifying
// FSEC is in correct location -Jacob
__attribute__ ((section(".flashconfig"), used))
const uint8_t flashconfigbytes[16] = {
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, // Backdoor Verif Key 28.3.1
//
// Protecting the first 8k of Flash memory from being over-written while running (bootloader protection)
// Still possible to overwrite the bootloader using an external flashing device
// For more details see:
// http://cache.freescale.com/files/training/doc/dwf/AMF_ENT_T1031_Boston.pdf (page 8)
// http://cache.freescale.com/files/microcontrollers/doc/app_note/AN4507.pdf
// http://cache.freescale.com/files/32bit/doc/ref_manual/K20P64M72SF1RM.pdf (28.34.6)
//
0xFF, 0xFF, 0xFF, 0xFF, // Program Flash Protection Bytes FPROT0-3 // XXX TODO PROTECT
0xBE, // Flash security byte FSEC
0x03, // Flash nonvolatile option byte FOPT
0xFF, // EEPROM Protection Byte FEPROT
0xFF, // Data Flash Protection Byte FDPROT
};
#endif
// ----- Functions -----
#if ( defined(_mk20dx128vlf5_) || defined(_mk20dx256vlh7_) ) && defined(_bootloader_) // Bootloader Section
__attribute__((noreturn))
static inline void jump_to_app( uintptr_t addr )
{
// addr is in r0
__asm__("ldr sp, [%[addr], #0]\n"
"ldr pc, [%[addr], #4]"
:: [addr] "r" (addr));
// NOTREACHED
__builtin_unreachable();
}
#endif
void *memset( void *addr, int val, unsigned int len )
{
char *buf = addr;
for (; len > 0; --len, ++buf)
*buf = val;
return (addr);
}
int memcmp( const void *a, const void *b, unsigned int len )
{
const uint8_t *ap = a, *bp = b;
int val = 0;
for (; len > 0 && (val = *ap - *bp) == 0; --len, ++ap, ++bp)
/* NOTHING */;
return (val);
}
void *memcpy( void *dst, const void *src, unsigned int len )
{
char *dstbuf = dst;
const char *srcbuf = src;
for (; len > 0; --len, ++dstbuf, ++srcbuf)
*dstbuf = *srcbuf;
return (dst);
}
// ----- Chip Entry Point -----
__attribute__ ((section(".startup")))
void ResetHandler()
{
#if ( defined(_mk20dx128vlf5_) || defined(_mk20dx256vlh7_) ) && defined(_bootloader_) // Bootloader Section
extern uint32_t _app_rom;
// We treat _app_rom as pointer to directly read the stack
// pointer and check for valid app code. This is no fool
// proof method, but it should help for the first flash.
//
// Purposefully disabling the watchdog *after* the reset check this way
// if the chip goes into an odd state we'll reset to the bootloader (invalid firmware image)
// RCM_SRS0 & 0x20
//
// Also checking for ARM lock-up signal (invalid firmware image)
// RCM_SRS1 & 0x02
if ( // PIN (External Reset Pin/Switch)
RCM_SRS0 & 0x40
// WDOG (Watchdog timeout)
|| RCM_SRS0 & 0x20
// LOCKUP (ARM Core LOCKUP event)
|| RCM_SRS1 & 0x02
// Blank flash check
|| _app_rom == 0xffffffff
// Software reset
|| memcmp( (uint8_t*)&VBAT, sys_reset_to_loader_magic, sizeof(sys_reset_to_loader_magic) ) == 0
)
{
memset( (uint8_t*)&VBAT, 0, sizeof(VBAT) );
}
else
{
uint32_t addr = (uintptr_t)&_app_rom;
SCB_VTOR = addr; // relocate vector table
jump_to_app( addr );
}
#endif
// Disable Watchdog
WDOG_UNLOCK = WDOG_UNLOCK_SEQ1;
WDOG_UNLOCK = WDOG_UNLOCK_SEQ2;
WDOG_STCTRLH = WDOG_STCTRLH_ALLOWUPDATE;
uint32_t *src = (uint32_t*)&_etext;
uint32_t *dest = (uint32_t*)&_sdata;
// Enable clocks to always-used peripherals
SIM_SCGC5 = 0x00043F82; // Clocks active to all GPIO
SIM_SCGC6 = SIM_SCGC6_FTM0 | SIM_SCGC6_FTM1 | SIM_SCGC6_ADC0 | SIM_SCGC6_FTFL;
#if defined(_mk20dx128_)
SIM_SCGC6 |= SIM_SCGC6_RTC;
#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 < (uint32_t*)&_edata ) *dest++ = *src++;
dest = (uint32_t*)&_sbss;
while ( dest < (uint32_t*)&_ebss ) *dest++ = 0;
// MCHCK / Kiibohd-dfu
#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 and Kiibohd-dfu (mk20dx256vlh7)
#else
SCB_VTOR = 0; // use vector table in flash
// default all interrupts to medium priority level
for ( unsigned int 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
#if !defined(_bootloader_)
// Initialize the SysTick counter
SYST_RVR = (F_CPU / 1000) - 1;
SYST_CSR = SYST_CSR_CLKSOURCE | SYST_CSR_TICKINT | SYST_CSR_ENABLE;
__enable_irq();
#else
// Disable Watchdog for bootloader
WDOG_STCTRLH &= ~WDOG_STCTRLH_WDOGEN;
#endif
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;
}
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