In the past, you need modify rtc_api.c in mbed-dev source code. From this revision, you can just use RTC function all of conditions (Normal, Reset, Stand-by, Power OFF).
Note
From now on, you do NOT need any modification for mbed-dev library because STM team updates rtc_api.c source code and support RTC function under reset & standby condition includes power off condition (You need additional VBAT back-up hardware).
Please refer following NOTE information.
/users/kenjiArai/notebook/nucleo-series-rtc-control-under-power-onoff-and-re/
Diff: main.cpp
- Revision:
- 14:4b03106ece1f
- Parent:
- 13:c1f984932e98
--- a/main.cpp Mon Jan 11 07:55:27 2021 +0000 +++ b/main.cpp Sat Mar 06 08:29:51 2021 +0000 @@ -6,7 +6,7 @@ * http://www7b.biglobe.ne.jp/~kenjia/ * https://os.mbed.com/users/kenjiArai/ * Created: January 17th, 2015 - * Revised: January 11th, 2021 + * Revised: March 6th, 2021 */ /* mbed library now suports RTC continuous operation at Reset & Power ON/OFF @@ -51,11 +51,13 @@ // Include -------------------------------------------------------------------- #include "mbed.h" +#include "uart_as_stdio.h" // Definition ----------------------------------------------------------------- #if defined(TARGET_DISCO_F746NG) \ || defined(TARGET_NUCLEO_F746ZG) \ || defined(TARGET_DISCO_F769NI) \ + || defined(TARGET_DISCO_F469NI) \ || defined(TARGET_NUCLEO_F446ZE) \ || defined(TARGET_NUCLEO_H743ZI2) #define PUSHED_SW 1 // Active high @@ -67,13 +69,11 @@ #define PUSHED_SW 0 // Active low #endif -#define LONGLONGTIME 2147483647 +#define LONGLONGTIME 2147483647s // Object --------------------------------------------------------------------- DigitalIn userSW(USER_BUTTON); DigitalOut myled(LED1); // Indicate the sampling period -// Create a BufferedSerial object to be used by the system I/O retarget code -static BufferedSerial pc(USBTX, USBRX, 9600); // RAM ------------------------------------------------------------------------ @@ -102,9 +102,9 @@ puts("\r\n\r\nTest Nucleo RTC Function."); print_revision(); myled = !myled; - thread_sleep_for(500); + ThisThread::sleep_for(500ms); myled = !myled; - thread_sleep_for(500); + ThisThread::sleep_for(500ms); while(true) { seconds = time(NULL); strftime(buf, 50, " %B %d,'%y, %H:%M:%S\r\n", localtime(&seconds)); @@ -114,15 +114,15 @@ puts("\r"); wait_counter = 0; while (seconds == time(NULL)) { - if (pc.readable() == 1) { - pc.read(buf,1); // dummy read + if (readable() == 1) { + buf[0] = getc(); // dummy read time_enter_mode(); } if (userSW == PUSHED_SW) { // goto sleep while (userSW == PUSHED_SW) { - thread_sleep_for(10); + ThisThread::sleep_for(10ms); } - thread_sleep_for(10); + ThisThread::sleep_for(10ms); puts("Entered the standby mode. "); #if defined(TARGET_NUCLEO_F303K8) || defined(TARGET_NUCLEO_L432KC) puts("Please change A0 level for wake-up(Reset)."); @@ -132,43 +132,28 @@ myled = 0; InterruptIn usr_sw(USER_BUTTON); - thread_sleep_for(1000); + ThisThread::sleep_for(1s); DigitalIn dmy0(LED1); DigitalIn dmy1(USBTX); DigitalIn dmy2(USBRX); usr_sw.fall(&usr_sw_irq); // actual push or chattering - thread_sleep_for(LONGLONGTIME); + sleep_preparation(); + ThisThread::sleep_for(LONGLONGTIME); } - thread_sleep_for(50); + ThisThread::sleep_for(50ms); if (++wait_counter > (2000 / 50)) { break; } } // delete previous strings - printf("\033[2A"); - puts(""); // null - uint8_t n = strlen(msg0) + strlen(msg1); - memset(buf, ' ', 64); - if (n > 64) { - n -= 64; - pc.write(buf, 64); - } - if (n > 64) { - pc.write(buf, 64); - } else { - pc.write(buf, n); - } - printf("\033[G"); + // https://en.wikipedia.org/wiki/ANSI_escape_code#CSIsection + // \33[ = CSI sequences, 1A=Cursor Up (one line), 2K=Erase in Line(all) + // G=Cursor Horizontal Absolute + printf("\33[1A\033[2K\033[G"); myled = !myled; } } -// the system I/O retarget -FileHandle *mbed::mbed_override_console(int fd) -{ - return &pc; -} - // Interrupt for wake up static void usr_sw_irq(void) { @@ -182,13 +167,12 @@ char linebuf[64]; puts("Set time into RTC."); - puts(" e.g. >21 1 6 12 34 56 -> January 06,'21, 12:34:56"); + puts(" e.g. >21 3 3 3 33 33 -> March 03,'21, 03:33:33"); puts(" If time is fine, just hit enter key."); - linebuf[0] = '>'; - pc.write(linebuf, 1); + putc('>'); ptr = linebuf; get_line(ptr, sizeof(linebuf)); - puts("\r"); + putc('\r'); chk_and_set_time(ptr); } @@ -251,12 +235,10 @@ static void get_line(char *buff, int32_t len) { char c; - char bf[8]; int32_t idx = 0; for (;;) { - pc.read(bf, 1); - c = bf[0]; + c = getc(); //printf("0x%x \r\n", c); if (c == '\r') { buff[idx++] = c; @@ -266,16 +248,15 @@ idx--; const char bf_bs[] = {0x1b, '[', '1', 'D', ' ', 0x1b, '[', '1', 'D'}; - pc.write(bf_bs, 9); + printf(bf_bs, 9); } if (((uint8_t)c >= ' ') && (idx < len - 1)) { buff[idx++] = c; - pc.write(bf, 1); + putc(c); } } buff[idx] = 0; - bf[0] = '\n'; - pc.write(bf, 1); + putc('\n'); } // Check key input strings and set time