LPC MicrocontrollersのトピックRe: LPC2478 Reset problem

LPC2478 Reset problem

lpcware — Wed, 15 Jun 2016 19:52:55 GMT

Content originally posted in LPCWare by tonko on Thu Nov 15 00:53:43 MST 2012
I have problems with reset on LPC2478 Board.
Board start normaly almost every time, but in very rare cases LPC2478 does not start.
For example Today I try to reset it aprox. 200 times and it always start properly.
Yesterday happends few times one after another that LPC2478 didn't start.

I checked if BOOT-Loader is active, but Flash Magic didn't conect with LPC.
Quartz 12Mhz does not start in case of reset failure.
On P2[10] I have pull-up 10K to VCC.
On Reset pin I have only 10K resistor to VCC. I know that there should be also capacitor to GND, but for now I don't have it, and I want to find reason why Reset does not work properly before I will put capacitor to GND.

Is it possible that 0.1uF capacitor from Reset to GND will solve problem permanently ?
LPC2478 has Brown-out detect circuit and I think that there should be no problems if I don't have capacitor.
Or should I use reset generator chip with delayed reset (TPS3801 or similar) ?

Any suggestions appreciated

Re: LPC2478 Reset problem

lpcware — Wed, 15 Jun 2016 19:52:55 GMT

Content originally posted in LPCWare by barny on Wed Dec 04 01:56:03 MST 2013
Hi,

Did you have any solutions to this problem?
I have also been experiencing the same with an LPC2387 processor, i can't get it to reset.
I don't think fitting a capacitor will solve your problem as my circuit has a capacitor and i am having reset issues.
I will make a post if i find anything which will help.
Thanks

Re: LPC2478 Reset problem

lpcware — Wed, 15 Jun 2016 19:52:56 GMT

Content originally posted in LPCWare by santoshb on Thu Sep 04 02:13:20 MST 2014
Hello,

I am using LPC2478 uc.
i have used MCP120-315 as reset ic and 14.7456MHz crystal and capacitor value is 22pf.
i have checked the Reset signal and it is ok because after POWER-ON it goes to High.
i have also checked the power supply and it is ok and VCC is 3.34v.

But i tried to see the 14.7456MHz clock frequency, but it is not coming.

My Board is new, on board only Power supply and LPC2478 related components are mounted.

Can anybody help me!