Low Power Testing of an MCU Development Board

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This article is from the Breadboard Community’s free evaluation activity for the “Lingdong Mini-F5333 Development Board”.

The MM32F5333 is a high-performance MCU launched by Lingdong Microelectronics, featuring multiple power-saving operating modes to meet different requirements for power management applications, and detailed tests of power supply current characteristics. In this article, we will introduce the power control (PWR) of the MM32F5333 and implement low power mode-related functions.Power Supply System of MM32F5333The power supply system of MM32F5333 has 4 power domains

VDDA and VSSA analog power supply domains

Provide voltage for the chip’s analog modules, used for ADC modules, internal reference voltage, internal temperature sensor, and PLL, etc. Therefore, the stability of the power supply affects the performance of the analog modules. VREF+ and VREF- provide reference voltage for the ADC.

VDD domain

The VDD domain mainly supplies power to the PMU, IWDG IO ports, and provides power to the core, built-in digital peripherals, and memory through voltage regulators.

Backup domain

The backup domain mainly powers the RTC, backup registers, and external low-speed clock oscillator LSE.

CORE domain

The CORE domain mainly powers the chip’s core, memory, and peripherals. It is enabled by default after power-up, and when entering low-power standby mode, the chip will hardware-select to turn off this CORE domain, which will automatically turn on after waking up. Power Manager The Power-On Reset (POR) and Power-Down Reset (PDR) of the chip have a complete POR and PDR circuit. This ensures that when the supply voltage reaches the chip’s minimum operating voltage, the system can operate normally. When VDD falls below the specified POR/PDR limit voltage, the system remains in a reset state, and the NRST reset pin is at a low level. For details on reset duration (tRSTTEMPO) and other POR and PDR details, please refer to the electrical characteristics section of the datasheet. Low Power Testing of an MCU Development Board

PVD Programmable Voltage Detector The PVD (Programmable Voltage Detector) can be used to monitor the chip’s supply voltage and generate an interrupt when the supply voltage drops below a given threshold, allowing software to perform emergency handling. An interrupt is also generated when the supply voltage recovers above the given threshold, allowing software to handle power restoration. Power Consumption Control Modes If the goal of reducing chip current consumption is not achieved, various low-power modes provided by the MCU can be utilized to save power. The chip has six low-power modes. Low Power Run Mode: The CORE domain operates in low power mode, with memory and peripherals also operating in low power. Sleep Mode: The CORE domain operates in normal power mode while the CPU enters sleep mode, and memory and peripherals operate in normal power mode. Low Power Sleep Mode: The CORE domain operates in low power sleep mode, with the CPU entering low power sleep mode, while memory and peripherals operate in low power. Stop Mode: The CORE domain operates in low power mode, only retaining the contents of registers and RAM. Deep Stop Mode: The CORE domain operates in an even lower power mode, only retaining the contents of registers and RAM. Standby Mode: The CORE domain stops receiving power. All registers and SRAM contents are lost except for the backup circuit and backup domain. Deep Stop Mode Experiment The MCU is powered by VDD_M. We can remove the shorting cap and connect the power supply to measure MCU power consumption.

Code Analysis The code first blinks an LED 20 times, then uses

PWR_Pretreatment();

to set the GPIO mode and configure external interrupts to wake up,

RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWRDBG, ENABLE);

to enable the PWR clock

PWR_EnterSTOPMode(PWR_Regulator_LowPower, PWR_STOPEntry_WFI);

to set it to enter Deep Stop

PWR_Reinitialize();

to restore the chip’s initialization

/***********************************************************************************************************************  * @brief  * @note   none  * @param  none  * @retval none  *********************************************************************************************************************/void PWR_DeepStop_EXTI_Wakeup_Sample(void){    uint8_t i = 0;    printf("\r\nTest %s", __FUNCTION__);    while (1)    {        printf("\r\n--&gt;Running...");        for (i = 0; i &lt; 20; i++)        {            PLATFORM_LED_Toggle(LED1);            PLATFORM_DelayMS(100);        }        PWR_Pretreatment();        /* Deep Stop Mode */        RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWRDBG, ENABLE);        PWR_EnterSTOPMode(PWR_Regulator_LowPower, PWR_STOPEntry_WFI);        PWR_Reinitialize();    }}

Experimental Phenomenon

The LED on the board cannot light up due to being powered by VDD, so an external LED is used.

The MCU power supply is around 5.1V, and the power consumption when the LED is lit is about 20mA.

The MCU enters low power mode at 256 microamps.

The manual states that Deep Stop is at 112.7 microamps, which is reasonable since I am providing power greater than 5V. Now Lingdong has improved a lot compared to two years ago.

This article is from the Breadboard Community’s free evaluation activity for the “Lingdong Mini-F5333 Development Board”.

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