Lpc2000

Hello,

You talked about the 3.3V supply and that things worked at 2.5V, 
however, you did not mention what was happening with the 1.8V supply. 
Since the core and memory run from the 1.8V supply, you might want to 
monitor what is going on there to see if it sheds any light onto the 
problem.

Jim

--- In lpc2000@yahoogroups.com, "tsvetanusunov" <tusunov@m...> wrote:
> Hello,
> This is a message which I posted last Friday on Philips 
> microcontroller forum. It seems that nobody from Philips is reading 
> this forum though as the only one who responded was Leon who 
observed 
> the same problem to one of his boards too, so I cross post here 
with 
> hope that somebody with more information/experience on LPC2106 
would 
> help:
> 
> ----QUOTE---
> Hi everybody, 
> 
> We have designed few development boards for LPC2106. 
> The schematics are posted at http://www.olimex.com/dev 
> Now we are running lot of 250 pcs LPC-P1 boards and experience the 
> following problem: if we program simple blinking led program into 
> LPC2106 flash and then disconnect and re-connect power supply in 
> random timely manner on 10 % of the boards sometimes LED doesn't 
> start to blink i.e. program is not executing, but after several 
> plug/unplugs LED start to blink. 
> In both cases i.e. program run or program doesn't run oscillator is 
> working with same frequency and amplitude i.e. it's not oscillator 
> powerup problem. 
> It's not reset problem also as even if we hold reset button while 
> plug/unplug and release reset button after power supply is 
stabilized 
> i.e. 1 second the code still may not run. 
> The power supply is adjusted to be exactly 3.3V with 1% resistors 
on 
> LM1117. 
> An interesting thing happens if we decrease input power supply (by 
> adding the Z diode i.e. disconnect Z_J jumper) in this case LM1117 
> have no enough Vin to make 3.3V and decrease output to 2.5V but 
here 
> is the interesting part: all boards which run the code in randomly 
> manner now are working each time if the Vcc is 2.5V! 
> As I wrote above this happend to only 10% of the boards all other 
90% 
> works solid no matter what power supply is. 
> I looked desperately on Philips LPC2106 web for technical support 
> link to report this issue but there apparently have not such, so I 
> decided to post this here in the forum. 
> 
> So any ideas? 
> 
> Best regards 
> Tsvetan
> ---END QUOTE---