101 lines
2.6 KiB
C
101 lines
2.6 KiB
C
/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <libopencm3/stm32/f1/rcc.h>
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#include <libopencm3/stm32/f1/gpio.h>
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#include <libopencm3/stm32/dbgmcu.h>
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#include <libopencm3/cm3/scs.h>
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#include <libopencm3/cm3/tpiu.h>
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#include <libopencm3/cm3/itm.h>
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void clock_setup(void)
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{
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rcc_clock_setup_in_hse_8mhz_out_72mhz();
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/* Enable GPIOC clock. */
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rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPCEN);
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}
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void trace_setup(void)
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{
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/* Enable trace subsystem (we'll use ITM and TPIU) */
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SCS_DEMCR |= SCS_DEMCR_TRCENA;
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/* Use Manchester code for asynchronous transmission */
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TPIU_SPPR = TPIU_SPPR_ASYNC_MANCHESTER;
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TPIU_ACPR = 7;
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/* Data width is 1 byte */
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TPIU_CSPSR = TPIU_CSPSR_BYTE;
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/* Formatter and flush control */
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TPIU_FFCR &= ~TPIU_FFCR_ENFCONT;
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/* Enable TRACESWO pin for async mode */
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DBGMCU_CR = DBGMCU_CR_TRACE_IOEN | DBGMCU_CR_TRACE_MODE_ASYNC;
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/* Unlock access to ITM registers */
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/* FIXME: Magic numbers... Is this Cortex-M3 generic? */
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*((volatile uint32_t*)0xE0000FB0) = 0xC5ACCE55;
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/* Enable ITM with ID = 1 */
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ITM_TCR = (1 << 16) | ITM_TCR_ITMENA;
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/* Enable stimulus port 1 */
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ITM_TER[0] = 1;
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}
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void gpio_setup(void)
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{
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/* Set GPIO12 (in GPIO port C) to 'output push-pull'. */
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gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_2_MHZ,
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GPIO_CNF_OUTPUT_PUSHPULL, GPIO12);
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}
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void trace_send_blocking(char c)
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{
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while(!(ITM_STIM[0] & ITM_STIM_FIFOREADY));
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ITM_STIM[0] = c;
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}
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int main(void)
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{
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int i, j = 0, c = 0;
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clock_setup();
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gpio_setup();
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trace_setup();
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/* Blink the LED (PC12) on the board with every transmitted byte. */
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while (1) {
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gpio_toggle(GPIOC, GPIO12); /* LED on/off */
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trace_send_blocking(c + '0');
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c = (c == 9) ? 0 : c + 1; /* Increment c. */
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if ((j++ % 80) == 0) { /* Newline after line full. */
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trace_send_blocking('\r');
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trace_send_blocking('\n');
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}
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for (i = 0; i < 800000; i++) /* Wait a bit. */
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__asm__("NOP");
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}
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return 0;
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}
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