startup reset

[bleumers_j]

Posted on December 08, 2003 at 11:40

startup reset

[bleumers_j]

Posted on November 28, 2003 at 09:36

Hi,

Sometimes my st7lite29 application doesn't start when i switch on the power. When i add a reset network (1µF cap to gound and 100 kohm to +5V) it works fine any time.

It is absolutely no problem for me to add those two components, but i seem to be the only one who has to do this. Maybe i'm doing something wrong... Ex. is it necessary to switch on the LVD?

Greets.

[delser9]

Posted on November 28, 2003 at 10:12

Hello joble

according to datasheet p112, it is indeed necessary to use LVD, or a reset circuit. You are not the only one who does need it.

[bleumers_j]

Posted on December 02, 2003 at 09:35

What is the best solution, the LVD or the external RC-network?

The external RC seems to me the most reliable.

[jatin]

Posted on December 02, 2003 at 12:40

Incase you use internal reset circuit(LVD), you will have to connnect 0.01 uf capacitor between GND and the reset pin.

[delser9]

Posted on December 03, 2003 at 03:01

I have done it with LVD, and it works fine! I never tried a reset-circuit because it is more expensive than LVD, and I never had any problem with the reliability of the LVD.

[bleumers_j]

Posted on December 08, 2003 at 09:22

Ok, the LVD is totaly clear to me now. I'm going to remove the rc and use the lvd.

Just one more question: Is it ok to use the highest treshold voltage (4.1V) for a 5V supply. I suppose it is, but just want to be sure.

Thanks!

[delser9]

Posted on December 08, 2003 at 11:40

Yes, it is if you have a normaly filtered power supply. Maybe you should also use the AVD to safely shut down the mcu (depends on your application), before it is internally reset.