在AT32 F425内部配有RTC计时器,用它来计时并在相应函数的配合下可免除计时过程中所遇到的进制处理问题,在使用串口通信的情况下,其执行效果如图1所示。 图1 运行效果 此外,若将RTC与OLED屏结合起来,则可以轻松地实现电子时钟的功能。 实现图2计时效果的主程序为: int main(void)
{
exint_init_type exint_init_struct;
ertc_time_type time;
uint32_t temp = 0;
system_clock_config();
nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);
at32_board_init();
uart_print_init(115200);
crm_periph_clock_enable(CRM_PWC_PERIPH_CLOCK, TRUE);
pwc_battery_powered_domain_access(TRUE);
if (ertc_bpr_data_read(ERTC_DT1) != 0x1234)
{
printf("ertc has not been initialized\r\n\r\n");
ertc_config();
}
else
{
printf("ertc has been initialized\r\n\r\n");
ertc_wait_update();
ertc_flag_clear(ERTC_ALAF_FLAG);
exint_flag_clear(EXINT_LINE_17);
}
exint_default_para_init(&exint_init_struct);
exint_init_struct.line_enable = TRUE;
exint_init_struct.line_mode = EXINT_LINE_INTERRUPUT;
exint_init_struct.line_select = EXINT_LINE_17;
exint_init_struct.line_polarity = EXINT_TRIGGER_RISING_EDGE;
exint_init(&exint_init_struct);
nvic_irq_enable(ERTC_IRQn, 0, 1);
app_oled_init();
OLED_Init();
OLED_Clear();
OLED_ShowString(0,0,"AT32F425",16);
OLED_ShowString(0,2,"OLED & RTC",16);
OLED_ShowString(8,4,"20 - -",16);
OLED_ShowString(24,6," : :",16);
while(1)
{
ertc_calendar_get(&time);
if(temp != time.sec)
{
temp = time.sec;
OLED_ShowNum(24,4,time.year,2,16);
OLED_ShowNum(48,4,time.month,2,16);
OLED_ShowNum(72,4,time.day,2,16);
OLED_ShowNum(24,6,time.hour,2,16);
OLED_ShowNum(48,6,time.min,2,16);
OLED_ShowNum(72,6,time.sec,2,16);
}
}
}
该程序的处理流程为: 首先进行RTC初始化,然后判别识别标志,若未设置初始计时值,则读取程序中的初始值来计时。否则,会在已有的计时值基础上进行计时处理,其显示效果如图2所示。 图2 显示效果 其中RTC初始计时值在该函数中设置或修改: void ertc_config(void)
{
crm_periph_clock_enable(CRM_PWC_PERIPH_CLOCK, TRUE);
pwc_battery_powered_domain_access(TRUE);
crm_battery_powered_domain_reset(TRUE);
crm_battery_powered_domain_reset(FALSE);
#if defined (ERTC_CLOCK_SOURCE_LICK)
crm_clock_source_enable(CRM_CLOCK_SOURCE_LICK, TRUE);
while(crm_flag_get(CRM_LICK_STABLE_FLAG) == RESET)
{
}
crm_ertc_clock_select(CRM_ERTC_CLOCK_LICK);
ertc_clk_div_b = 255;
ertc_clk_div_a = 127;
#elif defined (ERTC_CLOCK_SOURCE_LEXT)
crm_clock_source_enable(CRM_CLOCK_SOURCE_LEXT, TRUE);
while(crm_flag_get(CRM_LEXT_STABLE_FLAG) == RESET)
{
}
crm_ertc_clock_select(CRM_ERTC_CLOCK_LEXT);
ertc_clk_div_b = 255;
ertc_clk_div_a = 127;
#endif
crm_ertc_clock_enable(TRUE);
ertc_reset();
ertc_wait_update();
ertc_divider_set(ertc_clk_div_a, ertc_clk_div_b);
ertc_hour_mode_set(ERTC_HOUR_MODE_24);
ertc_date_set(22, 3, 2, 3);
ertc_time_set(12, 0, 0, ERTC_AM);
ertc_alarm_mask_set(ERTC_ALA, ERTC_ALARM_MASK_DATE_WEEK);
ertc_alarm_week_date_select(ERTC_ALA, ERTC_SLECT_DATE);
ertc_flag_clear(ERTC_ALAF_FLAG);
ertc_bpr_data_write(ERTC_DT1, 0x1234);
}
由此可见RTC计时还是十分有用的,并且也十分好用。
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