Why is my code sometimes running sometimes not ?

[antonius]

Posted on October 08, 2013 at 01:50

Guys,

Why is my code sometimes running sometimes not ? When I plug in J-Link, it's stable but if I plug it out, it's not stable ?? Is it because a power supply from USB ? Any ideas ? Thanks

[Tesla DeLorean]

Posted on October 08, 2013 at 02:36

The universe of problems is pretty large, I could get my magic eight ball out?

If you think it's a supply issue, then use a bench supply, and observe current draw. Track down what happens when the debugger is not attached, output diagnostic information via a serial port, or identify progress with GPIO or LED. Make sure you have a Hard Fault handler that can output data about faults.

[antonius]

Posted on October 08, 2013 at 13:01 or because I left my boot 1 hanging ? I boot from flash...

[antonius]

Posted on October 08, 2013 at 13:03

with LED blinker test it's stable, I'm using 2.4'' LCD, could it be the cause ? I have less power to turn it on ?

Now it's on after trying to reset few times....

[frankmeyer9]

Posted on October 08, 2013 at 17:15

Power consumption can be a problem with LCD displays. Supplying by USB might not be sufficient, as I can confirm. But that should be easy to find out.

LCD displays need relatively long delays at startup, to ramp up internal voltage converters - up into hundreds of milliseconds. Check the datasheet of your display. They usually provide an example initialization sequence, which you can compare with your code.

[jj2]

Posted on October 08, 2013 at 23:36

Appreciate all advice thus far - but perhaps this, ''When I plug in J-Link, it's stable but if I plug it out, it's not stable'' deserves further regard?

If that probe attachment improves things - as you state - might that suggest inadequate Reset circuit handling and/or JTAG pins not properly, ''pulled-up?''  Thus - w/JTAG probe present - those connections/signals are rendered ''proper'' - and when absent - improper connections assert...  To remove ''inadequate power'' from the mix - suggest that you open the connection to Lcd's backlight - likely the biggest power-hog on your board - and see if issue resolves...

[antonius]

Posted on October 09, 2013 at 01:43

I put 10uF capacitor on VDD3,as suggested on datasheet and I call it stable now, not sure....but everytime startup, I must push reset button few seconds to make it on...I'm using external power supply now

The first time I applied power supply, LCD was off, I need to push reset button about 1 second to make it on, any ideas why ? Please have a look on my reset and JTAG circuit, in case I need a fix on it, thanks ________________ Attachments : STM32F103V.pdf : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I07u&d=%2Fa%2F0X0000000baT%2FdXSDV2fn9ZU.1ZLAaJRHwN_QoR1Rqe9FnQc8jd_FdX4&asPdf=false

[antonius]

Posted on October 16, 2013 at 00:32

If I'm using USB as power supply, it's not easy to on it, even I push reset button so long..

but if I'm using 1A transformer, I can make it start after pushing the reset button for a few seconds, is it because of the LCD consuming a lot of power ? I'm using 2.4'' LCD with ILI9325 controller... thanks

[antonius]

Posted on October 16, 2013 at 00:48 I'm gonna use Amp meter to see the current draw.....and get back to you guys... It's 132 mA on 5V input, I'm using 1A transformer and LCD backlight is on, I need to push reset button for few seconds to make it on and stable.....any ideas why ? thanks for the suggestion

[jj2]

Posted on October 16, 2013 at 22:37

Your first post stated, ''When I plug in J-Link, it's stable but if I plug it out, it's not stable ??''

Does this, ''JLink connection'' continue in making things stable?  (appears it does not - from the bulk of your follow-on writings) As others have stated - LCD Controllers - upon power-up - often require an unusually long time to become, ''Ready.''  Does your MCU Reset process also reset the LCD Controller?  If it does not - that added ''MCU-only'' Reset may provide the added time required by your LCD... Many LCD Controllers may ''signal'' their ''readiness'' to accept initialization & data.  Your compliance w/this is an ideal means to gain stable & repeatable LCD operation...