LPC2148 Reset Problem

Thread Starter

praveen130789

Joined Mar 11, 2014
3
Hi, i had built a circuit of LPC2148 Development Board, which uses FT232RL to download the program through USB, I am unable to find out whats the problem is all about, everything is going fine including downloading the hex file to the controller, but after the hex file is downloaded, the program is not getting executed automatically, also when i press the reset button also the program is not executing, however if i switch off and switch on the board twice or thrice, the programs runs. what may be the problem ???

I have attached the circuit below, all the grounds are made common in the circuit.
 

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pwdixon

Joined Oct 11, 2012
488
Is this a professional pcb or a prototype you have assembled yourself?
What are the physical distances between the crystal/caps/processor?
 

Thread Starter

praveen130789

Joined Mar 11, 2014
3
Its just a prototyping PCB i have done, Physical distance between processor and crystal is ~ 0.7 cms.

Voltages on controller power pins is almost 3.6V, will the decoupling on controller power pins solve the issue of reset ??

Initially Reset pin is High when pressed the reset switch, voltage on reset pin goes to exact zero i have checked it in oscilloscope
 

pwdixon

Joined Oct 11, 2012
488
Its just a prototyping PCB i have done, Physical distance between processor and crystal is ~ 0.7 cms.

Voltages on controller power pins is almost 3.6V, will the decoupling on controller power pins solve the issue of reset ??

Initially Reset pin is High when pressed the reset switch, voltage on reset pin goes to exact zero i have checked it in oscilloscope
Processors usually want the crystal and caps close so 0.7cm is pretty good.

Decoupling can't make things worse and could well sort the problem it's worth a try.
 
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