Example Code 请见雅特力官网示例代码《SC0007_AT32F4xx_RTC_毫秒计时》。 因 AT32F403A, AT32F407, AT32F403, AT32F413 的 RTC 硬 件 结 构 相 同 ， 请 参 考 项 目 工 程AT32F403A_407_Firmware_Library。用 AT-START-F403 V1.2 下载验证时，请将 R7 焊上 0 欧电阻。因 AT32F415, AT32F421 的 ERTC 硬件结构相同，请参考项目工程 AT32F415_Firmware_Library。AT32F403A RTC 设置：
- typedef struct
- {
- __IO uint8_t hour; /*!< specifies the hours of calendar. */
- __IO uint8_t min; /*!< specifies the minutes of calendar. */
- __IO uint8_t sec; /*!< specifies the second of calendar. */
- __IO uint16_t msec; /*!< specifies the millisecond of calendar. */
- } calendar_type;
- calendar_type time_struct;
- /* config calendar */
- time_struct.hour = 12;
- time_struct.min = 0;
- time_struct.sec = 0;
- time_struct.msec = 100;
- rtc_init(&time_struct);
- uint8_t rtc_init(calendar_type *calendar)
- {
- /* enable pwc and bpr clocks */
- crm_periph_clock_enable(CRM_PWC_PERIPH_CLOCK, TRUE);
- crm_periph_clock_enable(CRM_BPR_PERIPH_CLOCK, TRUE);
- /* enable the battery-powered domain write operations */
- pwc_battery_powered_domain_access(TRUE);
- /* reset battery-powered domain register */
- bpr_reset();
- /* enable the lext osc */
- crm_clock_source_enable(CRM_CLOCK_SOURCE_LEXT, TRUE);
- /* wait lext is ready */
- while(crm_flag_get(CRM_LEXT_STABLE_FLAG) == RESET);
- /* select the rtc clock source */
- crm_rtc_clock_select(CRM_RTC_CLOCK_LEXT);
- /* enable rtc clock */
- crm_rtc_clock_enable(TRUE);
- /* wait for rtc registers update */
- rtc_wait_update_finish();
- /* wait for the register write to complete */
- rtc_wait_config_finish();
-
- /* set rtc divider: set rtc period to 1sec */
- rtc_divider_set(32);
-
- /* wait for the register write to complete */
- rtc_wait_config_finish();
- /* set time */
- rtc_time_set(calendar);
- /* writes data to bpr register */
- bpr_data_write(BPR_DATA1, 0x1234);
-
- return 1;
- }
- void ertc_config(void)
- {
- /* enable the pwc clock interface */
- crm_periph_clock_enable(CRM_PWC_PERIPH_CLOCK, TRUE);
-
- /* allow access to ertc */
- pwc_battery_powered_domain_access(TRUE);
- /* reset ertc domain */
- crm_battery_powered_domain_reset(TRUE);
- crm_battery_powered_domain_reset(FALSE);
-
- #if defined (ERTC_CLOCK_SOURCE_LICK)
- /* enable the lick osc */
- crm_clock_source_enable(CRM_CLOCK_SOURCE_LICK, TRUE);
- /* wait till lick is ready */
- while(crm_flag_get(CRM_LICK_STABLE_FLAG) == RESET)
- {
- }
- /* select the ertc clock source */
- crm_ertc_clock_select(CRM_ERTC_CLOCK_LICK);
-
- /* ertc second(1hz) = ertc_clk(lick) / (ertc_clk_div_a + 1) * (ertc_clk_div_b + 1) */
- ertc_clk_div_b = 999;
- ertc_clk_div_a = 32;
- #elif defined (ERTC_CLOCK_SOURCE_LEXT)
- /* enable the lext osc */
- crm_clock_source_enable(CRM_CLOCK_SOURCE_LEXT, TRUE);
- /* wait till lext is ready */
- while(crm_flag_get(CRM_LEXT_STABLE_FLAG) == RESET)
- {
- }
- /* select the ertc clock source */
- crm_ertc_clock_select(CRM_ERTC_CLOCK_LEXT);
- /* ertc second(1hz) = ertc_clk / (ertc_clk_div_a + 1) * (ertc_clk_div_b + 1) */
- ertc_clk_div_b = 999;
- ertc_clk_div_a = 32;
- #endif
- /* enable the ertc clock */
- crm_ertc_clock_enable(TRUE);
- /* deinitializes the ertc registers */
- ertc_reset();
- /* wait for ertc registers update */
- ertc_wait_update();
-
- /* configure the ertc divider */
- ertc_divider_set(ertc_clk_div_a, ertc_clk_div_b);
-
- /* configure the ertc hour mode */
- ertc_hour_mode_set(ERTC_HOUR_MODE_24);
-
- /* set date: 2021-05-01 */
- ertc_date_set(21, 5, 1, 5);
-
- /* set time: 12:00:00 */
- ertc_time_set(12, 0, 0, ERTC_AM);
- /* indicator for the ertc configuration */
- ertc_bpr_data_write(ERTC_DT1, 0x1234);
- }
1. 修改 RTC 设置时需修改写入备份域寄存器的值(如下代码)，或者是断主电源的同时拨掉纽扣电池；bpr_data_write(BPR_DATA1, 0x1234);
2. 程序中 RTC 分频系数寄存器（RTC_DIVH/RTC_DIVL）设置时要实际计算值减 1，因为寄存器会自动加 1，时钟频率为 = fRTCCLK/（DIV[19：0]+1）；ERTC 预分频器寄存器(ERTC_DIV) 设置时 DIVA/DIVB要实际计算值减 1, 因为寄存器会自动加 1，日历时钟=ERTC_CLK/((DIVA+1)x(DIVB+1))。
3. AT32F403A 与 AT32F415 获取毫秒的差别在于 AT32F403A 是通过分频，获得 1ms 时基，如下AT32F403A RTC 框图（最小可获得时基 61us）； AT32F415 是在 1s 时基，通过亚秒寄存器（ERTC_SBS）获得同步分频值，如下 AT32F415 ERTC 框图，计算得到毫秒值 SBS = (DIVB - SBS ) / (DIVB + 1 )。
4. 实际示波器测试和打印结果
| 
楼主
