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/
main.cpp
- Committer:
- kenjiArai
- Date:
- 2020-08-01
- Revision:
- 11:2e514d955a2b
- Parent:
- 10:806cfec92eb6
- Child:
- 12:8cb1f89541d1
File content as of revision 11:2e514d955a2b:
/* * mbed Application program * RTC (inside STM32x CPU) test program * * Copyright (c) 2015,'16,'17,'20 Kenji Arai / JH1PJL * http://www7b.biglobe.ne.jp/~kenjia/ * https://os.mbed.com/users/kenjiArai/ * Created: January 17th, 2015 * Revised: August 1st, 2020 */ /* mbed library now suports RTC continuous operation at Reset & Power ON/OFF -------------------------------------------------------------------------- In the past, rtc_api.c (inside mbed) alway made a reset RTC registers when user push a reset buttom or terninate a power. Even if user configures a back-up circuit for RTC, mbed board could not keep proper time. --> Right now, you don't worry thoese issue. */ /* ----- Tested board ----- / Reset: / Stanby: / power off and restart: Nucleo-F401RE / ok / ok / ok (need following Back-up Circuit) Nucleo-F411RE / ok / ok / ok (need following Back-up Circuit) Nucleo-F446RE / ok / ok / ok (need following Back-up Circuit) not support on Mbed-os6.2.0 Nucleo-F334R8 Nucleo-L476RG / ok / ok / ok (need following Back-up Circuit) DISCO-L45VG-IOT/ ok / ok / ok (Need additional hardware) Nucleo-L152RE / ok / ok / no check (Need additional hardware) Nucleo-L073RZ / ok / ok / no check (Need additional hardware) not support on Mbed-os6.2.0 Nucleo-L053R8 < Back-up circuit > CN7 VIN <- SBD <- 330 Ohm <- CR2032 + - -> CN7 GND Remove SB45 Zero Ohm resistor ----- PLEASE REFER FOLLOWS ---- https://os.mbed.com/users/kenjiArai/notebook/ nucleo-series-rtc-control-under-power-onoff-and-re/ */ // Include -------------------------------------------------------------------- #include "mbed.h" // Definition ----------------------------------------------------------------- #if (defined(TARGET_STM32F746NG) || defined(TARGET_STM32F746ZG)) #define PUSHED_SW 1 // Active high #else #define PUSHED_SW 0 // Active low #endif #define LONGLONGTIME 2147483647 // 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 ------------------------------------------------------------------------ // ROM / Constant data -------------------------------------------------------- const char *const msg0 = "Is a time correct? If no, please hit any key. "; const char *const msg1 = "<Push USER SW then enter the Standby mode> "; // Function prototypes -------------------------------------------------------- FileHandle *mbed::mbed_override_console(int fd); static void time_enter_mode(void); static void chk_and_set_time(char *ptr); static int32_t xatoi (char **str, int32_t *res); static void get_line (char *buff, int32_t len); static void usr_sw_irq(void); extern void print_revision(void); //------------------------------------------------------------------------------ // Control Program //------------------------------------------------------------------------------ int main() { char buf[64]; time_t seconds; uint8_t wait_counter = 0; puts("\r\n\r\nTest Nucleo RTC Function."); print_revision(); myled = !myled; thread_sleep_for(500); myled = !myled; thread_sleep_for(500); while(true) { seconds = time(NULL); strftime(buf, 50, " %B %d,'%y, %H:%M:%S\r\n", localtime(&seconds)); printf("[Time] %s", buf); printf("%s", msg0); printf("%s", msg1); puts("\r"); wait_counter = 0; while (seconds == time(NULL)) { if (pc.readable() == 1) { pc.read(buf,1); // dummy read time_enter_mode(); } if (userSW == PUSHED_SW) { // goto sleep while (userSW == PUSHED_SW) { thread_sleep_for(10); } thread_sleep_for(10); puts("Entered the standby mode. "); puts("Please push USER BUTTON to wake-up(Reset)."); myled = 0; InterruptIn usr_sw(USER_BUTTON); thread_sleep_for(1000); DigitalIn dmy0(LED1); DigitalIn dmy1(USBTX); DigitalIn dmy2(USBRX); usr_sw.fall(&usr_sw_irq); thread_sleep_for(LONGLONGTIME); } thread_sleep_for(50); 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"); 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) { system_reset(); // restart from RESET condition } // Time adjustment static void time_enter_mode(void) { char *ptr; char linebuf[64]; puts("Set time into RTC."); puts(" e.g. >20 8 1 12 34 56 -> August 01,'20, 12:34:56"); puts(" If time is fine, just hit enter key."); linebuf[0] = '>'; pc.write(linebuf, 1); ptr = linebuf; get_line(ptr, sizeof(linebuf)); puts("\r"); chk_and_set_time(ptr); } // Change string -> integer static int32_t xatoi(char **str, int32_t *res) { uint32_t val; uint8_t c, radix, s = 0; while ((c = **str) == ' ') (*str)++; if (c == '-') { s = 1; c = *(++(*str)); } if (c == '0') { c = *(++(*str)); if (c <= ' ') { *res = 0; return 1; } if (c == 'x') { radix = 16; c = *(++(*str)); } else { if (c == 'b') { radix = 2; c = *(++(*str)); } else { if ((c >= '0')&&(c <= '9')) { radix = 8; } else { return 0; } } } } else { if ((c < '1')||(c > '9')) { return 0; } radix = 10; } val = 0; while (c > ' ') { if (c >= 'a') c -= 0x20; c -= '0'; if (c >= 17) { c -= 7; if (c <= 9) return 0; } if (c >= radix) return 0; val = val * radix + c; c = *(++(*str)); } if (s) val = -val; *res = val; return 1; } // Get key input data 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]; //printf("0x%x \r\n", c); if (c == '\r') { buff[idx++] = c; break; } if ((c == '\b') && idx) { idx--; const char bf_bs[] = {0x1b, '[', '1', 'D', ' ', 0x1b, '[', '1', 'D'}; pc.write(bf_bs, 9); } if (((uint8_t)c >= ' ') && (idx < len - 1)) { buff[idx++] = c; pc.write(bf, 1); } } buff[idx] = 0; bf[0] = '\n'; pc.write(bf, 1); } // Check key input strings and set time static void chk_and_set_time(char *ptr) { int32_t p1; struct tm t; time_t seconds; if (xatoi(&ptr, &p1)) { t.tm_year = (uint8_t)p1 + 100; printf("Year:%d ",p1); xatoi( &ptr, &p1 ); t.tm_mon = (uint8_t)p1 - 1; printf("Month:%d ",p1); xatoi( &ptr, &p1 ); t.tm_mday = (uint8_t)p1; printf("Day:%d ",p1); xatoi( &ptr, &p1 ); t.tm_hour = (uint8_t)p1; printf("Hour:%d ",p1); xatoi( &ptr, &p1 ); t.tm_min = (uint8_t)p1; printf("Min:%d ",p1); xatoi( &ptr, &p1 ); t.tm_sec = (uint8_t)p1; printf("Sec: %d \r\n",p1); } else { return; } seconds = mktime(&t); set_time(seconds); // Show Time with several example // ex.1 printf( "Date: %04d/%02d/%02d, %02d:%02d:%02d\r\n", t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, t.tm_hour, t.tm_min, t.tm_sec ); char buf[64]; // ex.2 strftime(buf, 40, "%x %X", localtime(&seconds)); printf("Date: %s\r\n", buf); // ex.3 strftime(buf, 40, "%I:%M:%S %p (%Y/%m/%d)", localtime(&seconds)); printf("Date: %s\r\n", buf); // ex.4 strftime(buf, 40, "%B %d,'%y, %H:%M:%S", localtime(&seconds)); printf("Date: %s\r\n", buf); }