/* * This file is part of the libopencm3 project. * * Copyright (C) 2009 Uwe Hermann * * 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 . */ #include #include #include #include #include #include void clock_setup(void) { rcc_clock_setup_in_hse_8mhz_out_72mhz(); /* Enable GPIOC clock. */ rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPCEN); } 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; /* Data width is 1 byte. */ TPIU_CSPSR = TPIU_CSPSR_BYTE; /* 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 u32 *)0xE0000FB0) = 0xC5ACCE55; /* Enable ITM with ID = 1. */ ITM_TCR = (1 << 16) | ITM_TCR_ITMENA; /* Enable stimulus port 1. */ ITM_TER[0] = 1; } 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); } void trace_send_blocking(char c) { while (!(ITM_STIM[0] & ITM_STIM_FIFOREADY)) ; ITM_STIM[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; }