low power on discovery board

[MikeAtETI]

Posted on January 10, 2012 at 17:22

I'm trying to do something really simple, take the STM32L discovery, put some code in it and measure the current across JP1 (in the off position as the manual suggests).... However, I can't seem to get down to the low power levels suggested, does anyone have any example code they could share for this?

My quick copy/paste from the current measuring example isn't performing:

GPIO_InitTypeDef GPIO_InitStructure;
/*!< Set MSION bit */
RCC->CR |= (uint32_t)0x00000100;
/*!< Reset SW[1:0], HPRE[3:0], PPRE1[2:0], PPRE2[2:0], MCOSEL[2:0] and MCOPRE[2:0] bits */
RCC->CFGR &= (uint32_t)0x88FFC00C;
/*!< Reset HSION, HSEON, CSSON and PLLON bits */
RCC->CR &= (uint32_t)0xEEFEFFFE;
/*!< Reset HSEBYP bit */
RCC->CR &= (uint32_t)0xFFFBFFFF;
/*!< Reset PLLSRC, PLLMUL[3:0] and PLLDIV[1:0] bits */
RCC->CFGR &= (uint32_t)0xFF02FFFF;
/*!< Disable all interrupts */
RCC->CIR = 0x00000000;
__IO uint32_t MSIStatus = 0;
/* SYSCLK, HCLK, PCLK2 and PCLK1 configuration ---------------------------*/
if
((RCC->CR & RCC_CR_MSIRDY) != RESET)
{
MSIStatus = (uint32_t)0x01;
}
else
{
MSIStatus = (uint32_t)0x00;
}
if
(MSIStatus == (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;
RCC->ICSCR &= (uint32_t)((uint32_t)~(RCC_ICSCR_MSIRANGE));
RCC->ICSCR |= (uint32_t)RCC_ICSCR_MSIRANGE_0;
/* Select MSI as system clock source */
RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
RCC->CFGR |= (uint32_t)RCC_CFGR_SW_MSI;
/* Wait till MSI is used as system clock source */
while
((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)RCC_CFGR_SWS_MSI)
{
}
}
else
{
/* If MSI fails to start-up, the application will have wrong clock
configuration. User can add here some code to deal with this error */
}
#ifdef VECT_TAB_SRAM
SCB->VTOR = SRAM_BASE | 0x0; 
/* Vector Table Relocation in Internal SRAM. */
#else
SCB->VTOR = FLASH_BASE | 0x0; 
/* Vector Table Relocation in Internal FLASH. */
#endif
/* Keep debugger connection during SLEEP (debugging) */
DBGMCU_Config(DBGMCU_SLEEP, ENABLE);
/* Keep debugger connection during STOP (debugging) */
DBGMCU_Config(DBGMCU_STOP, ENABLE);
/* IWDG stopped when core is halted (debugging) */
DBGMCU_Config(DBGMCU_IWDG_STOP, ENABLE);
// now we're going to try to shut down the micro to lowest power
// level
/* Enable HSI Clock */
RCC_HSICmd(ENABLE);
/*!< Wait till HSI is ready */
while
(RCC_GetFlagStatus(RCC_FLAG_HSIRDY) == RESET);
/* Set HSI as sys clock*/
RCC_SYSCLKConfig(RCC_SYSCLKSource_HSI);
/* Set MSI clock range to ~4.194MHz*/
RCC_MSIRangeConfig(RCC_MSIRange_6);
/* Enable the GPIOs clocks */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_GPIOB | RCC_AHBPeriph_GPIOC| RCC_AHBPeriph_GPIOD| RCC_AHBPeriph_GPIOE| RCC_AHBPeriph_GPIOH, ENABLE);
/* Enable comparator, LCD and PWR mngt clocks */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_COMP | RCC_APB1Periph_LCD | RCC_APB1Periph_PWR,ENABLE);
/* Enable ADC & SYSCFG clocks */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_SYSCFG , ENABLE);
/* Allow access to the RTC */
PWR_RTCAccessCmd(ENABLE);
/* Reset RTC Backup Domain */
RCC_RTCResetCmd(ENABLE);
RCC_RTCResetCmd(DISABLE);
/* LSE Enable */
RCC_LSEConfig(RCC_LSE_ON);
/* Wait until LSE is ready */
while
(RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET);
/* RTC Clock Source Selection */
RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);
/* Enable the RTC */
RCC_RTCCLKCmd(ENABLE);
/*Disable HSE*/
RCC_HSEConfig(RCC_HSE_OFF);
if
(RCC_GetFlagStatus(RCC_FLAG_HSERDY) != RESET )
{
/* Stay in infinite loop if HSE is not disabled*/
while
(1);
}
/* Configure all GPIO port pins in Analog input mode (trigger OFF) */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_All;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_400KHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIOD->MODER = 0xFFFFFFFF;
GPIOE->MODER = 0xFFFFFFFF;
GPIOH->MODER = 0xFFFFFFFF;
/* all GPIOA */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3 | GPIO_Pin_6| GPIO_Pin_7 \
| GPIO_Pin_13 | GPIO_Pin_14|GPIO_Pin_5 | GPIO_Pin_8 |GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_11 | GPIO_Pin_12 |GPIO_Pin_15 ;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* All GPIOC except PC13 which is used for mesurement */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3 | GPIO_Pin_4| GPIO_Pin_5 |GPIO_Pin_6| GPIO_Pin_7| GPIO_Pin_8 \
| GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_11 | GPIO_Pin_12 | GPIO_Pin_14 | GPIO_Pin_15 ;
GPIO_Init(GPIOC, &GPIO_InitStructure);
/* all GPIOB except PB6 and PB7 used for LED*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3 | GPIO_Pin_4| GPIO_Pin_5 | GPIO_Pin_8 \
| GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_11 | GPIO_Pin_12 |GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15 ;
GPIO_Init(GPIOB, &GPIO_InitStructure);
/* RCC system reset */
RCC_DeInit();
/* Select the Voltage Range 3 (1.2V) */
PWR_VoltageScalingConfig(PWR_VoltageScaling_Range3);
/* Wait Until the Voltage Regulator is ready */
while
(PWR_GetFlagStatus(PWR_FLAG_VOS) != RESET);
/* Configure the MSI frequency */
// RCC_MSIRangeConfig(RCC_MSIRange_0);
/* Select MSI as system clock source */
RCC_SYSCLKConfig(RCC_SYSCLKSource_MSI);
/* Wait until MSI is used as system clock source */
while
(RCC_GetSYSCLKSource() != 0x00);
RCC_HSICmd(DISABLE);
/* Disable HSE clock */
RCC_HSEConfig(RCC_HSE_OFF);
/* Disable LSI clock */
RCC_LSICmd(DISABLE);
/* Disable the RTC Wakeup Interrupt */
RTC_ITConfig(RTC_IT_WUT, DISABLE);
/*Disable fast wakeUp*/
PWR_FastWakeUpCmd(DISABLE);
/* Disable PVD */
PWR_PVDCmd(DISABLE);
/* Enable Ultra low power mode */
PWR_UltraLowPowerCmd(ENABLE);
/* To stop the sys tick for avoid IT */
SysTick->CTRL = 0;
while
(1)
{
PWR_EnterSTOPMode(PWR_Regulator_LowPower,PWR_STOPEntry_WFI);
}