STM32L Stop Mode

[terryhansen]

Posted on February 05, 2013 at 20:46

I cannot get stop mode current below 1.1 mA in the IAR STM32L152VB eval board. This is the code to prep and then go to stop mode:

lowPowerConfigGPIO();  (this configures all GPIO pins as ADC inputs)

PWR_FastWakeUpCmd(DISABLE);PWR_PVDCmd(DISABLE);PWR_UltraLowPowerCmd(ENABLE);RCC->AHBENR = 0;RCC->AHBLPENR = 0; RCC->APB1ENR =  RCC_APB1ENR_PWREN;RCC->APB2ENR = 0;SysTick->CTRL = 0;PWR_EnterSTOPMode(PWR_Regulator_LowPower, PWR_STOPEntry_WFI);while(1){ __no_operation();}The code is based on the STM32L Discovery firmware in STM32L_Discovery_Firmware_Pack_V1.0.2Stop mode on the STM32L Discovery board is about 47 uA. But on the IAR board it does not go below 1.1 mA.Any help seeing what I am doing wrong is much appreciated!Terry

[Tesla DeLorean]

Posted on February 05, 2013 at 22:01

It could be whatever else is powered, are you looking at a board level current, or chip level current?

Also I'd sleep in a loop lest it leave via interrupt or whatever.

while(1)
{
PWR_EnterSTOPMode(PWR_Regulator_LowPower, PWR_STOPEntry_WFI);
}

A WFI in a loop would be preferable to a NOP

[terryhansen]

Posted on February 06, 2013 at 02:11

I am sure the measurement I am doing is processor current, not board current.  The IAR board is set up to make it easy to measure processor current.  You just remove a 2-pin jumper and read the current across the pins.  There is another location to measure board current.

Thanks for the idea about the WFI loop.  I will give it a shot.Terry

[terryhansen]

Posted on February 06, 2013 at 17:52

Turns out it is my fault.  Having the J-Link loader/debugger connected to the board makes the micro consume right around 1 mA.  Not sure why this happens.  But when the J-Link is disconnected, processor current drops to under 100 uA.  That can be improved, but the big issue was the J-Link.

Thanks for the help.