219 lines
6.1 KiB
C
219 lines
6.1 KiB
C
/*
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* The MIT License (MIT)
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*
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* Copyright (c) 2019 Ha Thach (tinyusb.org)
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*
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* This file is part of the TinyUSB stack.
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*/
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#include "bsp/board.h"
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#include "board.h"
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#include "msp430.h"
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//--------------------------------------------------------------------+
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// Forward USB interrupt events to TinyUSB IRQ Handler
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//--------------------------------------------------------------------+
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void __attribute__ ((interrupt(USB_UBM_VECTOR))) USB_UBM_ISR(void)
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{
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tud_int_handler(0);
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}
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//--------------------------------------------------------------------+
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// MACRO TYPEDEF CONSTANT ENUM
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//--------------------------------------------------------------------+
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uint32_t cnt = 0;
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static void SystemClock_Config(void)
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{
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WDTCTL = WDTPW + WDTHOLD; // Disable watchdog.
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// Increase VCore to level 2- required for 16 MHz operation on this MCU.
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PMMCTL0 = PMMPW + PMMCOREV_2;
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UCSCTL3 = SELREF__XT2CLK; // FLL is fed by XT2.
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// XT1 used for ACLK (default- not used in this demo)
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P5SEL |= BIT4; // Required to enable XT1
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// Loop until XT1 fault flag is cleared.
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do
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{
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UCSCTL7 &= ~XT1LFOFFG;
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}while(UCSCTL7 & XT1LFOFFG);
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// XT2 is 4 MHz an external oscillator, use PLL to boost to 16 MHz.
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P5SEL |= BIT2; // Required to enable XT2.
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// Loop until XT2 fault flag is cleared
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do
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{
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UCSCTL7 &= ~XT2OFFG;
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}while(UCSCTL7 & XT2OFFG);
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// Kickstart the DCO into the correct frequency range, otherwise a
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// fault will occur.
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// FIXME: DCORSEL_6 should work according to datasheet params, but generates
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// a fault. I am not sure why it faults.
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UCSCTL1 = DCORSEL_7;
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UCSCTL2 = FLLD_2 + 3; // DCO freq = D * (N + 1) * (FLLREFCLK / n)
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// DCOCLKDIV freq = (N + 1) * (FLLREFCLK / n)
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// N = 3, D = 2, thus DCO freq = 32 MHz.
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// MCLK configured for 16 MHz using XT2.
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// SMCLK configured for 8 MHz using XT2.
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UCSCTL4 |= SELM__DCOCLKDIV + SELS__DCOCLKDIV;
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UCSCTL5 |= DIVM__16 + DIVS__2;
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// Now wait till everything's stabilized.
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do
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{
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UCSCTL7 &= ~(XT2OFFG + XT1LFOFFG + DCOFFG);
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SFRIFG1 &= ~OFIFG;
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}while(SFRIFG1 & OFIFG);
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// Configure Timer A to use SMCLK as a source. Count 1000 ticks at 1 MHz.
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TA0CCTL0 |= CCIE;
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TA0CCR0 = 999; // 1000 ticks.
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TA0CTL |= TASSEL_2 + ID_3 + MC__UP; // Use SMCLK, divide by 8, start timer.
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// Initialize USB power and PLL.
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USBKEYPID = USBKEY;
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// VUSB enabled automatically.
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// Wait two milliseconds to stabilize, per manual recommendation.
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uint32_t ms_elapsed = board_millis();
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do
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{
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while((board_millis() - ms_elapsed) < 2);
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}while(!(USBPWRCTL & USBBGVBV));
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// USB uses XT2 (4 MHz) directly. Enable the PLL.
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USBPLLDIVB |= USBPLL_SETCLK_4_0;
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USBPLLCTL |= (UPFDEN | UPLLEN);
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// Wait until PLL locks. Check every 2ms, per manual.
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ms_elapsed = board_millis();
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do
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{
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USBPLLIR &= ~USBOOLIFG;
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while((board_millis() - ms_elapsed) < 2);
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}while(USBPLLIR & USBOOLIFG);
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USBKEYPID = 0;
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}
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uint32_t wait = 0;
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void board_init(void)
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{
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__bis_SR_register(GIE); // Enable interrupts.
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SystemClock_Config();
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// Enable basic I/O.
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P1DIR |= LED_PIN; // LED output.
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P1REN |= BUTTON_PIN; // Internal resistor enable.
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P1OUT |= BUTTON_PIN; // Pullup.
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// Enable the backchannel UART (115200)
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P4DIR |= BIT5;
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P4SEL |= (BIT5 | BIT4);
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UCA1CTL1 |= (UCSSEL__SMCLK | UCSWRST); // Hold in reset, use SMCLK.
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UCA1BRW = 4;
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UCA1MCTL |= (UCBRF_3 | UCBRS_5 | UCOS16); // Overampling mode, 115200 baud.
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// Copied from manual.
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UCA1CTL1 &= ~UCSWRST;
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// Set up USB pins.
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USBKEYPID = USBKEY;
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USBPHYCTL |= PUSEL; // Convert USB D+/D- pins to USB functionality.
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USBKEYPID = 0;
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}
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//--------------------------------------------------------------------+
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// Board porting API
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//--------------------------------------------------------------------+
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void board_led_write(bool state)
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{
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if(state)
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{
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LED_PORT |= LED_PIN;
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}
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else
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{
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LED_PORT &= ~LED_PIN;
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}
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}
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uint32_t board_button_read(void)
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{
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return ((P1IN & BIT1) >> 1) == BUTTON_STATE_ACTIVE;
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}
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int board_uart_read(uint8_t * buf, int len)
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{
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for(int i = 0; i < len; i++)
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{
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// Wait until something to receive (cleared by reading buffer).
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while(!(UCA1IFG & UCRXIFG));
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buf[i] = UCA1RXBUF;
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}
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return len;
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}
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int board_uart_write(void const * buf, int len)
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{
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const char * char_buf = (const char *) buf;
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for(int i = 0; i < len; i++)
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{
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// Wait until TX buffer is empty (cleared by writing buffer).
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while(!(UCA1IFG & UCTXIFG));
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UCA1TXBUF = char_buf[i];
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}
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return len;
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}
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#if CFG_TUSB_OS == OPT_OS_NONE
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volatile uint32_t system_ticks = 0;
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void __attribute__ ((interrupt(TIMER0_A0_VECTOR))) TIMER0_A0_ISR (void)
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{
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system_ticks++;
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// TAxCCR0 CCIFG resets itself as soon as interrupt is invoked.
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}
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uint32_t board_millis(void)
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{
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uint32_t systick_mirror;
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// 32-bit update is not atomic on MSP430. We can read the bottom 16-bits,
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// an interrupt occurs, updates _all_ 32 bits, and then we return a
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// garbage value. And I've seen it happen!
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TA0CCTL0 &= ~CCIE;
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systick_mirror = system_ticks;
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TA0CCTL0 |= CCIE;
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return systick_mirror;
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}
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#endif
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