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/*
* This file is part of the libopencm3 project.
*
* Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/dbgmcu.h>
#include <libopencm3/cm3/scs.h>
#include <libopencm3/cm3/tpiu.h>
#include <libopencm3/cm3/itm.h>
static void clock_setup(void)
{
rcc_clock_setup_in_hse_8mhz_out_72mhz();
/* Enable GPIOC clock. */
rcc_periph_clock_enable(RCC_GPIOC);
}
static void trace_setup(void)
{
/* Enable trace subsystem (we'll use ITM and TPIU). */
SCS_DEMCR |= SCS_DEMCR_TRCENA;
/* Use Manchester code for asynchronous transmission. */
TPIU_SPPR = TPIU_SPPR_ASYNC_MANCHESTER;
TPIU_ACPR = 7;
/* Formatter and flush control. */
TPIU_FFCR &= ~TPIU_FFCR_ENFCONT;
/* Enable TRACESWO pin for async mode. */
DBGMCU_CR = DBGMCU_CR_TRACE_IOEN | DBGMCU_CR_TRACE_MODE_ASYNC;
/* Unlock access to ITM registers. */
/* FIXME: Magic numbers... Is this Cortex-M3 generic? */
*((volatile uint32_t *)0xE0000FB0) = 0xC5ACCE55;
/* Enable ITM with ID = 1. */
ITM_TCR = (1 << 16) | ITM_TCR_ITMENA;
/* Enable stimulus port 1. */
ITM_TER[0] = 1;
}
static void gpio_setup(void)
{
/* Set GPIO12 (in GPIO port C) to 'output push-pull'. */
gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_2_MHZ,
GPIO_CNF_OUTPUT_PUSHPULL, GPIO12);
}
static void trace_send_blocking(char c)
{
while (!(ITM_STIM8(0) & ITM_STIM_FIFOREADY))
;
ITM_STIM8(0) = c;
}
int main(void)
{
int i, j = 0, c = 0;
clock_setup();
gpio_setup();
trace_setup();
/* Blink the LED (PC12) on the board with every transmitted byte. */
while (1) {
gpio_toggle(GPIOC, GPIO12); /* LED on/off */
trace_send_blocking(c + '0');
c = (c == 9) ? 0 : c + 1; /* Increment c. */
if ((j++ % 80) == 0) { /* Newline after line full. */
trace_send_blocking('\r');
trace_send_blocking('\n');
}
for (i = 0; i < 800000; i++) /* Wait a bit. */
__asm__("nop");
}
return 0;
}