LPC4367 MCU getting locked

manish_sharma2 — Wed, 09 Dec 2020 05:14:27 GMT

Dear Sir,

we are using LPC4367 MCU in our design. It was observed that the MCU was getting locked and we need to erase it again to work on it.

While comparing with the reference schematic LPCXpresso43/18xx v3 Rev B, we found that the pin connected to JTAG programming is having different pullups.

IF_TDO_SWO: 100K pullup

IF_TMS_SWDIO: 100K pull up

IF_RST: 100K pull up

TCK-SWDCLK_TRGT: 2.2K pullup

IF_JTAG_TDI: No pull up

In my design we have used fixed 10K pull up. Can you please explain why different pullup are needed and what is the use of NX3DV2567GU,115 Analog switch.

Thanks

Manish Sharma

Re: LPC4367 MCU getting locked

ZhangJennie — Thu, 10 Dec 2020 10:35:44 GMT

Hi Manish Sharma,

Please follow this design considerations for your JTAG design.

https://community.nxp.com/t5/LPCXpresso-IDE-FAQs/Design-Considerations-for-Debug/m-p/469565#M44

WHy you wonder your MCU locking is due to Jtag design?

Have a nice day,

Jun Zhang

topic LPC4367 MCU getting locked in LPC Microcontrollers

LPC4367 MCU getting locked

Re: LPC4367 MCU getting locked