Hi,
I am working on a small project, for which i have created chip code, which i have tested and it works fine in Keil IDE. But the same when uploaded to chip behaves partly expected or totally unexpected. Some times the chip doesn't reset even done hardware reset.
I have checked it with 3 chips, but no success. My programmer seems fine as it is detecting attached chip and programming chip correctly.
In my project I need serial communication, which is also not working fine. Sometime the MCU skips sending or receiving characters, or doesn't respond to command event after hardware resets.
Could you please suggest me how to resolve this?
Let me know if any further information is required.
Details AT89S52, USB Programmer, C Programming language,
Regards,
Bhagirath
Hi Per Wastermark,
Keeping subsequent reset aside, it is also not working properly on initial power up. e.g. I have dumped simple P1 led blinking code to check programmers working status, it just blinks for 5 - 7 time accurately after that 2 -3 time blinks abruptly and then hangs(doesn't change the blinking status). I have dumped the code in 3 different MCU but no success.
Thanks Bhagirath.
You can have failures with the first reset too. It's just a question of ramp-up time for the supply voltages, or if there is any bounce when power is applied - bounces from plugging in mains cable or from the switch that turns on the power.
And starting the processor at a slightly low voltage could get it to start, but then overload the PSU (that is already busy trying to fill up all empty capacitances) resulting in the voltage dropping back enough to make the processor misbehave.
An RC reset really is a dicey concept - you never know when it will work well (no problems perceived) and what it will be a total disaster.