current value is 20mA

https://www.google.com/search?q=cr2032+continuous+discharge+current

 

Hello,
While i was waiting development board arrive to me, i am trying to learn PIC and i wonder is it possible to continue PWM output while the microcontroller in sleep mode for PIC10LF322. Because i am trying to get the minimum power consumption.

 

Hello,
While i was waiting development board arrive to me, i am trying to learn PIC and i wonder is it possible to continue PWM output while the microcontroller in sleep mode for PIC10LF322. Because i am trying to get the minimum power consumption.

Section 18.1.6 of the datasheet states that timer 2 is powered down in sleep mode which the PWM needs

So no, unfortunately

 

Thanks @click_here i got it.
Another question; I see a code like this for PIC10LF322:

PWM2_Init(50);
PWM2_Start();
PWM2_Set_Duty(255);

As seen above , i can divide a period to 255 portion. This mean is that i can use minimum 1/255 of the full intensity of the led. But i need to dim it more about at least 1/1000. Is it possible?

 

As seen above , i can

https://ww1.microchip.com/downloads...F320-322-Data-Sheet-40001585E.pdf#G18.1061472 (see from the top of the page)

 

Thanks @click_here i got it.
Another question; I see a code like this for PIC10LF322:

PWM2_Init(50);
PWM2_Start();
PWM2_Set_Duty(255);

As seen above , i can divide a period to 255 portion. This mean is that i can use minimum 1/255 of the full intensity of the led. But i need to dim it more about at least 1/1000. Is it possible?

Would you still see it if you dim it to 1/1000?

 

Would you still see it if you dim it to 1/1000?

@Ian0 i make this led worked with stm32L0 series and dim it to 1/10000 and still see it without any problem.

 

@Ian0 i make this led worked with stm32L0 series and dim it to 1/10000 and still see it without any problem.

Can’t you just increase the series resistance?

 

Can’t you just increase the series resistance?

Of course it is possible but this time system will be more inefficient isn't it? The more we increase the resistance, the more inefficient the system will be?

 

https://ww1.microchip.com/downloads...F320-322-Data-Sheet-40001585E.pdf#G18.1061472 (see from the top of the page)

As i understand with 32khz internal oscillator i can not handle grater than 255. If i am wrong please correct me.

 

Of course it is possible but this time system will be more inefficient isn't it? The more we increase the resistance, the more inefficient the system will be?

If the LED is driven by a resistor or a constant current source, then 100% duty cycle at 1mA dissipates exactly the same as 10% duty cycle at 10mA.
At very high LED currents the LED efficiency actually reduces.

 

You’re running an STM32 at 32KHz? That’s like powering the hydraulics of a bulldozer by bkowing into a tube.

Bob

 

You'll find info about drivers for flashlight LEDs at places like the Budget Light Forum, mainly based on ATtiny. But there are also very inexpensive microcontrollers from China:
https://cpldcpu.wordpress.com/2019/08/12/the-terrible-3-cent-mcu/
and here's an actual example of a very low current consumption LED flasher (average consumption of under 1.5 uA at 3V while blinking an LED):
https://cpldcpu.wordpress.com/2021/02/07/ultra-low-power-led-flasher/

 

Anyone remember the LM3909?

 

with 32khz internal oscillator

if the MCU has an on-chip analog comparator - you could use RC to shorten your pulse to a width - limited by the HW I/O delays at the signal chain? (no PWM required at all)

 

You'll find info about drivers for flashlight LEDs at places like the Budget Light Forum, mainly based on ATtiny. But there are also very inexpensive microcontrollers from China:
https://cpldcpu.wordpress.com/2019/08/12/the-terrible-3-cent-mcu/
and here's an actual example of a very low current consumption LED flasher (average consumption of under 1.5 uA at 3V while blinking an LED):
https://cpldcpu.wordpress.com/2021/02/07/ultra-low-power-led-flasher/

This is a very niche information thank you for your help.

 

if the MCU has an on-chip analog comparator - you could use RC to shorten your pulse to a width - limited by the HW I/O delays at the signal chain? (no PWM required at all)

Sorry but i couldn't understand what you want to say because i am not informed enough. If you can explain maybe i can try.

 

Is the LED to be flashing or permanently illuminated?

 

Is the LED to be flashing or permanently illuminated?

There will be some levels from zero to top maybe 30 levels. If possible i want to divide the duty cycle to 1k and assign this duty values to this levels.

 

Anyone remember the LM3909?

I sure do. I loved that chip. I put some in flashlights as beacons so you could find them in the dark, back in the days when a good flashlight used two D cells, a PR2 lamp, and was made by Bright Star.

​

A while ago I bought a couple of NOS LM3909s (well, SK10067 replacements) at about $5 each for nostalgia's sake. Now I am seeing them for $12.

​