8051's are extremely susceptible to electrical noise and fluctuations. They always go haywire. There is a chance when you are connecting the charger, its creating noise. Have you tried using an electrolytic cap in Vcc pin?
Datasheet says its "official" operating voltage is 4.0V to 5.5V @ 24MHz. In 3.7V it can loose its current vector and skip the smooth program instructions. I had these experience a lot. Lately I had to remove interupts. :bang:
--> minimal votage is 4.0VDatasheet says its "official" operating voltage is 4.0V to 5.5V
--> so 3.7V is out of specification.yes i have connected a 4.7uf cap between +3.7v
--> even 4.1V is near the lowest specified voltage. A short - even for microseconds - voltage drop may cause problems.89s52 shows 4.10v..
--> The microcontroller works in the MHz range. So the VCC capacitor must be able to be low ohmic in that frequency range. An electrolytic capacitor sure is not. What type of capacitor is it?i have connected a 4.7uf cap
Hi,
just reading the posts:
--> minimal votage is 4.0V
--> so 3.7V is out of specification.
--> even 4.1V is near the lowest specified voltage. A short - even for microseconds - voltage drop may cause problems.
--> The microcontroller works in the MHz range. So the VCC capacitor must be able to be low ohmic in that frequency range. An electrolytic capacitor sure is not. What type of capacitor is it?
Klaus
What Li ion charger controller you are using?? Some chargers uses "trickle" charge technique to charge batteries. That will cause a lot of noise.
Is your INT0 pin is taking some signal input? Are you sure the signal voltage is absolutely stable?
As what Klaus said, maybe you are pushing the limit of minimum power supply. Can you use step up output to power the controller too?
i am using 7805 ic to charge the battery.
You mean you are not using any Li ion charger IC, just the 5V regulator, and that 5v is fed to the battery directly??? This way you might blow up your battery. Li ion's are not so easy to charge. They need to follow proper charging technique. A simple 5v regulator won't suffice. Charging ICs like MC34673, MAX1737m, MC34673, etc. are needed. They follow a charging algorithm. These might also solve the glitch when you connect your regulator.
Have you connected a capacitor as shown in the datasheet at the output of the regulator?
3. As per the block diagram you posted, it seems you have connected the charger's +ve terminal with the battery and the step up circuit. I don't know what's the actual arrangement is, but if that is a hard wired connection, then your charger will get confused while charging the battery, as it have to monitor the battery's status and supply the right voltage and current for charging. That power (from regulated charging controller to the battery) cannot be shared with any other circuits.
i have placed a 4.7uf capacitor between 89S52 and battery cap(+) to battery(+) and cap(-) to battery (-). which i think has solved my problem....
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