time(NULL) of RTC example not synchronizing with RTC when using battery

sunnydaywest · January 16, 2024, 11:01pm

If I put this part in the RTC config it’s solved. I will create a ticket in mbed project.

#if defined __HAL_RCC_RTCAPB_CLK_ENABLE
    __HAL_RCC_RTCAPB_CLK_ENABLE();
#endif /* __HAL_RCC_RTCAPB_CLK_ENABLE */

github.com/ARMmbed/mbed-os

time(NULL) not returning real RTC value after reboot

opened 11:22PM - 16 Jan 24 UTC

lefebvresam

priority: untriaged component: untriaged

### Description of defect The following code starts counting at 12:00:00 AM a…fter each MCU reset and doesn't reflect the real RTC value: ``` int main() { while(1) { time_t seconds = time(NULL); char buffer[32]; strftime(buffer, 32, "%I:%M:%S %p", localtime(&seconds)); printf("%s \r", buffer); int i = 100000; while(i--); // keep busy (sleep gives programming issues with STLinkV2 clone and printf cannot flush) } } ``` After investigation the issue was solved when putting this code snippet in mbed_sdk_init() in mbed_overrides.c of STM target between the #if DEVICE_RTC/#endif lines or calling rtc_init() before the main function: ``` #if defined __HAL_RCC_RTCAPB_CLK_ENABLE __HAL_RCC_RTCAPB_CLK_ENABLE(); #endif /* __HAL_RCC_RTCAPB_CLK_ENABLE */ ``` #### Target(s) affected by this defect ? MCU_STM32U575xG inherited from MCU_STM32U5 custom_targets.json ``` { "MCU_STM32U575xG": { "inherits": [ "MCU_STM32U5" ], "public": false, "mbed_rom_size": "0x100000", "mbed_ram_size": "0xc0000", "extra_labels_add": [ "STM32U575xG" ], "macros_add": [ "STM32U575xx" ] }, "HMC20": { "inherits": [ "MCU_STM32U575xG" ], "overrides": { "clock_source" : "USE_PLL_HSE_XTAL", "lse_available" : "1", "lse_drive_load_level" : "RCC_LSEDRIVE_HIGH" }, "macros_add": [ "HSE_VALUE=10000000UL" ], "device_name": "HMC20" } } ``` #### Toolchain(s) (name and version) displaying this defect ? NA #### What version of Mbed-os are you using (tag or sha) ? Mbed 7.59.0 #### What version(s) of tools are you using. List all that apply (E.g. mbed-cli) CLI2 #### How is this defect reproduced ? Create a test project

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time(NULL) of RTC example not synchronizing with RTC when using battery

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