02064576e8
soruced originally from: https://github.com/libopencm3/libopencm3/pull/613 edited to drop the use of bin files, and switch to devices.data
58 lines
1.2 KiB
C
58 lines
1.2 KiB
C
#include <libopencm3/cm3/nvic.h>
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#include <libopencm3/cm3/systick.h>
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/* LM3S Specifics, usart and RCC */
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#include <libopencm3/lm3s/rcc.h>
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#include <libopencm3/lm3s/usart.h>
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static volatile uint32_t jiffies = 0u;
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static void printbanner(void)
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{
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char msg[] = "One second elapsed!\r\n";
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char *c = msg;
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while (*c != 0) {
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usart_send(USART0_BASE, (uint16_t )*c);
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c++;
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}
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}
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void sys_tick_handler(void)
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{
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jiffies++;
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}
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static inline uint32_t systick_app_config(uint32_t n_ticks)
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{
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/* constant from systick_set_reload -- as this returns something that's
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* * not void, this is the only possible error condition */
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if (n_ticks & ~0x00FFFFFF) {
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return 1;
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}
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systick_set_reload(n_ticks);
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systick_set_clocksource(1);
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systick_interrupt_enable();
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systick_counter_enable();
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return 0;
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}
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#define HZ 1000
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int main(void)
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{
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uint32_t last_time = 0;
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rcc_clock_setup_in_xtal_8mhz_out_50mhz();
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systick_app_config(HZ);
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nvic_set_priority(NVIC_SYSTICK_IRQ, 0);
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jiffies = 0;
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while(1) {
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if (jiffies > HZ) {
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printbanner();
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jiffies = 0;
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}
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}
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}
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