STM32L100 Discovery - low power mode

[marko23]

Posted on July 26, 2014 at 11:41

Hi all,

I have been trying to measure current consumption for low power sleep mode with STM32l100 Discovery board. I'm using most of the code gathered from STM32 standard peripherial library without any component attached to the board. I start by configuring maximum frequency using HSEBYP (using STlink clock) and PLL, and then using MSI with HCLK=32khz and entering sleep. Problem is that I cannot get less than ~1000uA and the measured current is not steady, but changing as much as 300uA (while measuring). I'm measuring by attaching amp meter on JP2 jumper. The only idea that I'm having is that R27 and R26 can interfere with measurements since that line by my calculations would spend about 285uA, which still is not explaining high current consumption. Please help, startup code that I'm using for clocks is:

__IO uint32_t StartUpCounter = 0, HSEStatus = 0;
/* SYSCLK, HCLK, PCLK2 and PCLK1 configuration ---------------------------*/
/* Set external clock (generated by ST-LINK chip) */
RCC->CR |= ((uint32_t)RCC_CR_HSEBYP);
/* Enable HSE */
RCC->CR |= ((uint32_t)RCC_CR_HSEON);
/* Wait till HSE is ready and if Time out is reached exit */
do
{
HSEStatus = RCC->CR & RCC_CR_HSERDY;
StartUpCounter++;
} 
while
((HSEStatus == 0) && (StartUpCounter != HSE_STARTUP_TIMEOUT));
if
((RCC->CR & RCC_CR_HSERDY) != RESET)
{
HSEStatus = (uint32_t)0x01;
}
else
{
HSEStatus = (uint32_t)0x00;
}
if
(HSEStatus == (uint32_t)0x01)
{
/* Enable 64-bit access */
FLASH->ACR |= FLASH_ACR_ACC64;
/* Enable Prefetch Buffer */
FLASH->ACR |= FLASH_ACR_PRFTEN;
/* Flash 1 wait state */
FLASH->ACR |= FLASH_ACR_LATENCY;
/* Power enable */
RCC->APB1ENR |= RCC_APB1ENR_PWREN;
/* Select the Voltage Range 1 (1.8 V) */
PWR->CR = PWR_CR_VOS_0;
/* Wait Until the Voltage Regulator is ready */
while
((PWR->CSR & PWR_CSR_VOSF) != RESET)
{
}
/* HCLK = SYSCLK /1*/
RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
/* PCLK2 = HCLK /1*/
RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
/* PCLK1 = HCLK /1*/
RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV1;
/* PLL configuration */
RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLMUL |
RCC_CFGR_PLLDIV));
RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMUL12 | RCC_CFGR_PLLDIV3);
/* Enable PLL */
RCC->CR |= RCC_CR_PLLON;
/* Wait till PLL is ready */
while
((RCC->CR & RCC_CR_PLLRDY) == 0)
{
}
/* Select PLL as system clock source */
RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;
/* Wait till PLL is used as system clock source */
while
((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)RCC_CFGR_SWS_PLL)
{
}
}
else
{
/* If HSE fails to start-up, the application will have wrong clock
configuration. User can add here some code to deal with this error */
}

sleep function:

/* HCLK = SYSCLK/2 = ~32KHz */
RCC_HCLKConfig(RCC_SYSCLK_Div2);
/* PCLK2 = HCLK */
RCC_PCLK2Config(RCC_HCLK_Div1);
/* PCLK1 = HCLK */
RCC_PCLK1Config(RCC_HCLK_Div1);
/* Set MSI clock range to 536KHz */
RCC_MSIRangeConfig(RCC_MSIRange_0);
/* Select MSI as system clock source */
RCC_SYSCLKConfig(RCC_SYSCLKSource_MSI);
/* Wait till MSI is used as system clock source */
while
(RCC_GetSYSCLKSource() != 0x00)
{
}
/* Flash 0 wait state */
FLASH_SetLatency(FLASH_Latency_0);
/* Disable Prefetch Buffer */
FLASH_PrefetchBufferCmd(DISABLE);
/* Disable 64-bit access */
FLASH_ReadAccess64Cmd(DISABLE);
/* Select the Voltage Range 2 (1.5V) */
PWR_VoltageScalingConfig(PWR_VoltageScaling_Range2);
/* Wait Until the Voltage Regulator is ready */
while
(PWR_GetFlagStatus(PWR_FLAG_VOS) != RESET)
{
}
/* Configure all GPIO as analog to reduce current consumption on non used IOs */
/* Enable GPIOs clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_GPIOB | RCC_AHBPeriph_GPIOC |
RCC_AHBPeriph_GPIOD | RCC_AHBPeriph_GPIOE | RCC_AHBPeriph_GPIOH |
RCC_AHBPeriph_GPIOF | RCC_AHBPeriph_GPIOG, ENABLE);
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_All;
GPIO_Init(GPIOC, &GPIO_InitStructure);
GPIO_Init(GPIOD, &GPIO_InitStructure);
GPIO_Init(GPIOE, &GPIO_InitStructure);
GPIO_Init(GPIOH, &GPIO_InitStructure);
GPIO_Init(GPIOF, &GPIO_InitStructure);
GPIO_Init(GPIOG, &GPIO_InitStructure);
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_Init(GPIOB, &GPIO_InitStructure);
/* Disable GPIOs clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_GPIOB | RCC_AHBPeriph_GPIOC |
RCC_AHBPeriph_GPIOD | RCC_AHBPeriph_GPIOE | RCC_AHBPeriph_GPIOH |
RCC_AHBPeriph_GPIOF | RCC_AHBPeriph_GPIOG, DISABLE);
RCC_DeInit();
/* Enter RUN LP Mode */
PWR_EnterLowPowerRunMode(ENABLE);
/* Wait until the system enters RUN LP and the Regulator is in LP mode */
while
(PWR_GetFlagStatus(PWR_FLAG_REGLP) == RESET)
{
}
PWR_UltraLowPowerCmd(ENABLE);
PWR_EnterSleepMode(PWR_Regulator_LowPower, PWR_SLEEPEntry_WFE);
/* Exit the RUN LP Mode */
PWR_EnterLowPowerRunMode(DISABLE);

and main funcion:

//enable GPIOC for input button, enable GPIOC AHBEN clock
InitializeApplication();
//disable all low power clocks (sync with normal clocks)
RCC->AHBLPENR = RCC->AHBENR;
RCC->APB1LPENR = RCC->APB1ENR;
RCC->APB2LPENR = RCC->APB2ENR;
while
(1) {
//led ON
GPIO_SetBits(GPIOC, GPIO_Pin_9);
//wait for user click
while
(GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_0)==0){}
//led OFF and goto low power
GPIO_ResetBits(GPIOC, GPIO_Pin_9);
STM32_PowerDown();
while
(1){
//test if got out of low power / blink LED
delay_ms(1);
GPIO_ToggleBits(GPIOC, GPIO_Pin_9);
}
}

Is there some misunderstanding about code or? This is not exactly a copy of STDPeriph library examples as I saw that sequence of some code is maybe not correct, but even with copy of demo I could not get low power numbers from MCU data sheets. Best regards, Marko

[os_kopernika]

Posted on July 26, 2014 at 22:18

''I have been trying to measure current consumption for low power sleep mode with STM32l100 Discovery board.''

It is STM32L-Discovery that comes with a microammeter(two ranges) and current consumption demo. Check its firmware. I didn't use ''low power sleep'' mode in my applications but I did use Stop mode with LCD and RTC running, periodically waking uC. It draws below 10uA then (averaged).

[marko23]

Posted on July 27, 2014 at 19:41

I have STM32L100 Discovery board, it is withouth current consumption firmware as far as I know.

[abraham]

Posted on October 12, 2014 at 13:58

Hello,

Remove R27, it take  ~300micro amper (3V/10K) and remove  also SB18 and now it will take you down to ~4-5micro amper. If you want to go down even more disconnect the ST linkI succeeded to have 1.45 micro amper