microcontroller with sleep status output?

[NiHaoMike]

Are there any microcontrollers with a sleep status output? In other words, the capability to set a GPIO output a logic level depending on whether the microcontroller is in sleep or in active mode, set by hardware? The main advantage I see is that for applications where the microcontroller goes to sleep often and is usually in the active state for a very short time, external peripherals (e.g. sensors) can start powering on a little sooner and reduce the active time needed. And be immune to strange bugs from forgetting to set a GPIO on entering or exiting sleep.

[BrianHG]

Bug in code not being able to set an IO before and after the sleep command?  Wouldn't this would be an impossibly difficult bug to create?

As for minimal advance powering up signal for external hardware, why not put the MCU into sleep in 32KHz ultra low power mode, then when waking up, in 32KHz, set the IO on and wait that infinitesimal small delay before changing the MCU clock back to full speed as a means of minimizing power consumption?

[NiHaoMike]

It's more for curiosity than a real need. As for how to forget to set a GPIO, maybe there's a time after initial development where there's a need to add another ISR and the requirement to set the GPIO is forgotten.

[Alex Eisenhut]

I put an ammeter on the power supply of a PIC I was debugging. Sleep means the current consumption goes to 0 as far as a milliammeter is concerned. Wasn't my code or my design so this was the quickest way to find out if the thing was indeed sleeping.

[AndyC_772]

Code: [Select]

void sleep (void)
{
  p_gpio_sleeping = 1;
  asm ("sleep");
  p_gpio_sleeping = 0;
}


[cgroen]

It's more for curiosity than a real need. As for how to forget to set a GPIO, maybe there's a time after initial development where there's a need to add another ISR and the requirement to set the GPIO is forgotten.

If you are afraid that you will forget to set/reset a GPIO pin in this particular situation, then what about the other million situations where you need to set a GPIO pin