LPC MicrocontrollersのトピックRe: LPC802 external reset pin not pull-up when restating

LPC802 external reset pin not pull-up when restating

join_ren — Tue, 17 Dec 2019 15:34:16 GMT

We are in the debugging LPC802.
There is a probability that the reset pin will not pull up when restarting.

Please tell me how to solve it. Thanks.

Reset Pin SCH:

LPC802 SCH

Power & Reset

Re: LPC802 external reset pin not pull-up when restating

jeremyzhou — Wed, 18 Dec 2019 02:56:04 GMT

Hi ,

Thank you for your interest in NXP Semiconductor products and
for the opportunity to serve you.
After having a brief review of the schematic, I don't find anything wrong with it, so I'd like to know what the ratio of boards encounters this phenomenon, I suspect that the phenomenon may be related to PCB manufacturing or soldering technique.

Have a great day,
TIC

-------------------------------------------------------------------------------
Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!

- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
-------------------------------------------------------------------------------

Re: LPC802 external reset pin not pull-up when restating

join_ren — Mon, 23 Dec 2019 06:25:28 GMT

Hi Jeremyzhou:

Thanks for your support.

"There is a probability that the reset pin will not pull up when restarting."

Actual testing :

1、This is abnormal LPC802's PCB can be restarting on the computer. Use 3.3v start-up time 2ms.

2、This is abnormal LPC802's PCB cann't be restarting on the customer device. Use 3.3v start-up time 8ms.

Could you tell me special requirement for LPC802 start-up ?

On the computer start up:

On the customer device start up:

Re: LPC802 external reset pin not pull-up when restating

jeremyzhou — Mon, 23 Dec 2019 09:07:28 GMT

Hi ，

Thanks for your reply.
Regarding the phenomenon, you should check the hardware design, especially the power supply, external crystal, reset pin, they're essential components of the minimum system.

Have a great day,
TIC

-------------------------------------------------------------------------------
Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!