本帖最后由 ddllxxrr 于 2015-4-7 20:58 编辑
这个RTT比昨天的RTC简单点。其原理也是先设RTC中断，然后，在中断里更新显示。
用户可以设一个数字，当程序运行到这个数字时，就显示一行报警的字样
以下是调有的显示函数
- static void refresh_display(void)
- {
- printf("%c[2J\r", 27);
- printf("Time: %u\n\r", (unsigned int)rtt_read_timer_value(RTT));
- /* Display alarm */
- if (g_uc_alarmed) {
- puts("!!! ALARM !!!\r");
- }
- /* Main menu */
- if (g_uc_state == STATE_MAIN_MENU) {
- puts("Menu:\n\r"
- " r - Reset timer\n\r"
- " s - Set alarm\r");
- if (g_uc_alarmed) {
- puts(" c - Clear alarm notification\r");
- }
- puts("\n\rChoice? ");
- } else {
- if (g_uc_state == STATE_SET_ALARM) {
- puts("Enter alarm time: ");
- if (g_ul_new_alarm != 0) {
- printf("%u", (unsigned)g_ul_new_alarm);
- }
- }
- }
- }
- void RTT_Handler(void)
- {
- uint32_t ul_status;
- /* Get RTT status */
- ul_status = rtt_get_status(RTT);
- /* Time has changed, refresh display */
- if ((ul_status & RTT_SR_RTTINC) == RTT_SR_RTTINC) {
- refresh_display();
- }
- /* Alarm */
- if ((ul_status & RTT_SR_ALMS) == RTT_SR_ALMS) {
- g_uc_alarmed = 1;
- refresh_display();
- }
- }
- /* User input loop */
- while (1) {
- /* Wait for user input */
- scanf("%c", (char *)&c);
- /* Main menu mode */
- if (g_uc_state == STATE_MAIN_MENU) {
- /* Reset timer */
- if (c == 'r') {
- configure_rtt();
- refresh_display();
- } else if (c == 's') { /* Set alarm */
- g_uc_state = STATE_SET_ALARM;
- g_ul_new_alarm = 0;
- refresh_display();
- } else { /* Clear alarm */
- if ((c == 'c') && g_uc_alarmed) {
- g_uc_alarmed = 0;
- refresh_display();
- }
- }
- } else if (g_uc_state == STATE_SET_ALARM) { /* Set alarm mode */
- /* Number */
- if ((c >= '0') && (c <= '9')) {
- g_ul_new_alarm = g_ul_new_alarm * 10 + c - '0';
- refresh_display();
- } else if (c == ASCII_BS) {
- printf("%c", c);
- g_ul_new_alarm /= 10;
- refresh_display();
- } else if (c == ASCII_CR) {
- /* Avoid newAlarm = 0 case */
- if (g_ul_new_alarm != 0) {
- rtt_write_alarm_time(RTT, g_ul_new_alarm);
- }
- g_uc_state = STATE_MAIN_MENU;
- refresh_display();
- }
- }
以下是运行截图：
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