LPC 4370 custom design board

[sujayp]

Dear NXP Technical Support Services,

I have a power supply board that supplies a Lpc4370  and other components of a system. When I measure the resistance between power  and GND using a multimeter I get the following readings:

   
    Between 3.3V and GND: 26 Ohms

The 3.3V and 1.2V rails have many decoupling caps around power supply pins of the LPc4370 microcontroller , are they the only cause for this much reduced isolation between these voltages and ground?

The system is running perfectly for couple of days , after running some trace unit testing , the system stops running with keil ulink pro   and now i am using the Keil ulink 2 and it was showing swd commmunication failure.

I am using Keil MDK 5.23 version .

Actually the if you know it is from the hardware problem  or  firware version in keil it was displaying V2.03.

Regards
sujay
 

[jeremyzhou]

Hi sujay p

Thank you for your interest in NXP Semiconductor products and 

for the opportunity to serve you.

I also use the multimeter to detect the resistance between the GND and VCC: 2.2K Ohms in the LPC-link2, so I think it must be something with your board. whether you detected other boards which work well and I wonder the these values.

Have a great day,

TIC

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[sujayp]

Hi,

The measurements are done when the system is powered OFF , when the power is  on the resistance between the VCC and Ground get open circuit , For   few days the programing the LPC4370FET256  it works fine ,   But i think   I  have run the  bad firmware using the kiel ulink pro , May be in regarding the  Code Read Protection [ CRP ]. 
now i am using the Keil ulink 2 may be due to that  but it still was displaying the SWD communication failure.

Please will  any one help in this regards.

[sujayp]

Hi,

Maybe my  latest programmed software has CRP enabled , If so how to delete the NXP Device LPC4370FET256  to re-enable the JTAG Device.