Best IC for my timer/stopwatch/countdown timer project.

[eebhoi01]

Hello,

Good day, I'm about to start a simple project. A device like that of a basketball timer, only that I am using it as timer for our native sport here in our locality.

I will be using an Atmega MCU as my main controller, I understand that MCU is not best to be used as timers, my question is could anyone please suggest an IC that I could look into that can do such purpose and can be interfaced with the MCU via SPI, i2C or UART. My second question is, am I right that RTC can be used for such purpose? I don't have any experience with RTC so please forgive my little knowledge. Thank you so much!

 

[FvM]

RTC is the usual choice for keeping time and date information. A pure stop watch and timer project won't necessarily need it. Consider that standard RTC chips (e.g. DS1337) don't provide higher time resolution than 1 second.

I presume everything can be well implemented in software with your ATmega processor.

 

[KlausST]

Hi,

I see no need for an RTC. Any microcontroller with an XTAL clock will do the job.
Use an uC internal timer/counter to generate a precise and useful timebase. 10ms....500ms.
Even witnout RTC it will be as precise as the XTAL clock. Some 10 ppm.

I understand that MCU is not best to be used as timers

What do you mean?

Klaus

 

[eebhoi01]

Hi,

I see no need for an RTC. Any microcontroller with an XTAL clock will do the job.
Use an uC internal timer/counter to generate a precise and useful timebase. 10ms....500ms.
Even witnout RTC it will be as precise as the XTAL clock. Some 10 ppm.


What do you mean?

Klaus

Before, there were high school students who ask for help on their project. Their project has a pendulum, they need to count the time interval for each swing of the pendulum and the total swings before it comes to a full stop. It was for their physics subject.

The only thing is we used arduino wayback then. We successfully implemented the code only that, when we compare the time interval recorded by the arduino against a real stopwatch it has a huge difference. That makes me assume that the MCU is not suitable for timers application.

 

[KlausST]

Hi,

when we compare the time interval recorded by the arduino against a real stopwatch it has a huge difference.

This surely is not a problem of the microcontroller, it is a problem of the used code.

Klaus