Problem using UART2 in release mode ...

alex80 · Joined: 05 Nov 2019 Posts: 4

Hello,

I am new in this forum but I regularly refer to some topics.

I have a problem using the UART2 of a dsPIC30F3013. I use MPLAB X 3.51 and CCS PCD compiler and my goal is very simple (see code below): I want to continuously send 2 characters on the serial port.

I compile and download the program with "Make and Program Device Main Project". I watch the U2TX pin with an oscilloscope. The program works perfectly as long as the programmer/debugger (Pickit 3) is connected. When I turn off the power, unplug the Pickit 3 and i power the microcontroller again, the U2TX pin no longer emit any characters.

Do you have an idea of the problem ? The future electronic card will have to be autonomous and the program will be more complex than this one.

Thank you.

Alex

Ttelmah · Joined: 11 Mar 2010 Posts: 19513

Classic one is no pullup on the MCLR pin. Chip won't run unless this pin is
pulled high and the programmer does do this, Something like a 20K
resistor on this to Vdd.

alex80 · Joined: 05 Nov 2019 Posts: 4

Hi Ttelmah,

Thanks for your response.

I already have a pullup resistor (10K) between MCLR and VDD.

If I blink an LED instead of emitting a character ... the program is working properly !!

Alex

Ttelmah · Joined: 11 Mar 2010 Posts: 19513

Are you sure you have programmed a _release_ version of the code?.
If you are working in MPLAB, this has to explicitly be done. A debug release
will run while the debugger is attached, but not without.

alex80 · Joined: 05 Nov 2019 Posts: 4

I'm not absolutely sure. I use the "Make and Program Device Main Project" button in MPLAB X.

Is there another way to configure the release mode?

Ttelmah · Joined: 11 Mar 2010 Posts: 19513

On the current releases of MPLAB-X use the big green arrow button on
the toolbar. It's an arrow down pointing into a chip. It automatically
switches to release mode, and programs the chip. By default MPLAB
builds with it's default configuration and if you have an ICD selected, this
is debug mode.

temtronic · Posted: Wed Nov 06, 2019 8:09 am

just a comment...
You can change the 'default' build mode in MPLAB v8.86 and later. I've set mine to 'release' several years ago since I always burn then test in the real World.

I don't know what happens with 'ICD', again, not the way I work...
Jay

alex80 · Joined: 05 Nov 2019 Posts: 4

Thank you for your responses.

I finally solved the problem. It was a hardware problem. There was a bad reset at power on.

I added an MCP100 on the MCLR pin and a capacitor beteween VDD and VSS. Now all is fine.

Thanks.

Alex