5 years, 1 month ago.

LPC1114 Problems

I developed some software on an LPC11U24 which I then ported to the Switch Science LPC1114 device. I loaded in the updated mbed boot loader file as instructed on the LPC1114 platform page

My problem is the system is very unstable on the LPC1114. After reset it comes up ok but crashes after a short while - and by crash I mean it will not respond to inputs.

I am at the point where I am ready to ditch the LPC1114 and go back to the LPC11U24 . . . which I would like to avoid.

Is there anything I am overlooking?

We really need some information. We can't do much with "It doesn't work". What code do you run? Which inputs?

posted by Erik - 16 Jun 2015

Probably not enough RAM memory...and debugging this is a difficult problem .

posted by Robert Spilleboudt 16 Jun 2015

Could very well be RAM indeed, but thats not that hard to debug.

posted by Erik - 16 Jun 2015

Here is the code for the LPC1114 version.


posted by Andrew R 16 Jun 2015

I checked on the resources usage by clicking on the build details - I am using 1.1k RAM. I'll try to see what it is with the program running - maybe its higher.

posted by Andrew R 16 Jun 2015

You are only using 25% of your RAM, however I had a similar issue where I was not exiting loops that stacked up and ran out of RAM. But then you would have the same issue with the other platform after a longer period. I would make sure your power supply is well decoupled close to the chip just in case of noise and I assume you remove the MCU from the programmer when testing as pin 28 and 14 are connected to the LED's. Do you need to define both InterruptIn and DigitalIn on the same pin? I just use InterruptIn.

posted by Paul Staron 16 Jun 2015

Paul, thanks for your comment about InteruptIn and DigitalIn - I will certainly try that. I have been trying the system out by just plugging in the dev board into my breadboard - same as I did with the LPC11U24. I was planning to lay a PCB out for the TSSOP20 version of the MCU once I got the prototype going. Is there any reason why I would need to plug the MCU directly into breadboard? I think the pin loading is light - I am pulling about 1mA at worst case from the active high pins,

posted by Andrew R 17 Jun 2015

1 Answer

5 years, 1 month ago.

It seems the LPC1114FN28 has only 4KB RAM , instead of 8KB the 11U24 has ... so it seems probable that you need more resources ... I have not compared the two devices , but at first glance it seems 1114FN28 is inferior , unless you need the DIP package ( do you really need it ? )

There is also some better version of 1114 with 8KB RAM , but it is not in DIP package

Regards, Christos

Thanks Christos.

Is there an easy way to check how much RAM my program is using with the mbed compiler?

posted by Andrew R 16 Jun 2015

Erik/Robert, thanks for your comments. Here is the link to my program

It works perfectly on the LPC11U24.

posted by Andrew R 16 Jun 2015