Reset on LPC1768

Hello,

to me it looks like a problem with the power supply.

If you switch on the power, all the devices in your circuit draw 
current. If this ist too much and the voltage drops below a certain 
level, the controller might end up in an undefined state.

Solution might be too change something on your power supply. Or maybe 
there is a parameter to delay the startup of your controller.

I hope this will help you!

Are there any loops in the initialisation which wait for bits to be 
set/cleared by the hardware (something like while 
(!(SOME_REG&SOMEMASK)){;})? IF so, check with "LED-blink-debugging" if 
the code "hangs" in such a loop. Did you try with the ISP interface 
connected and disconnected. Did you check the VCC, BSL and RST levels 
with a scope? Do you use code from NXP's CMSIS package to init the 
clock-system? If not, you may at least do a few tests with the code from 
the package.

Mk Bit wrote:
> Hello,
>
> to me it looks like a problem with the power supply.
>
> If you switch on the power, all the devices in your circuit draw
> current. If this ist too much and the voltage drops below a certain
> level, the controller might end up in an undefined state.
>
> Solution might be too change something on your power supply. Or maybe
> there is a parameter to delay the startup of your controller.
>
> I hope this will help you!

Thanks for your response. Ya it looks like problem hardware only.

I have herewith attached the circuit, It would be great if you check 
this circuit

The reset and isp circuit i have uploaded to this link
The RST# goes to controller pin 17.

Martin Thomas wrote:
> Are there any loops in the initialisation which wait for bits to be
> set/cleared by the hardware (something like while
> (!(SOME_REG&SOMEMASK)){;})? IF so, check with "LED-blink-debugging" if
> the code "hangs" in such a loop. Did you try with the ISP interface
> connected and disconnected. Did you check the VCC, BSL and RST levels
> with a scope? Do you use code from NXP's CMSIS package to init the
> clock-system? If not, you may at least do a few tests with the code from
> the package.

Thanks for your reply.

There are no loops in the initialization.

I have checked the VCC, BSL, RST lines

BSL line: default -> 3.1v
          After ISP switch - 0 -> 3.1v (the value changes from low to 
high)

Vcc line: Default -> 3.3 v
          After Reset - 3.3v

RST line : Default -> 1.7v
           After Reset - 0 -> 1.7v (the value changes from low to high)

RST out Line: Default -> 3.2v
            after reset - 0-> 3.2v (the value changes from low to high)

These lines seems to be working fine, Any suggestions to the possible 
problem??