Power Problem - ShiftBar

lpcware · ‎06-15-2016

Content originally posted in LPCWare by ralieghnet on Thu Jan 12 23:01:41 MST 2012
I'm having a problem delivering enough power with my LPC1343 to my ShiftBar. I have tried several different methods of powering the device. Through either the 5v with the LPC-Link attached or the 3.3v without the Link. This power is coming through a step down voltage regulator that has a user-selectable output of 5v or 3.3v with 3.0a max of current out. There is also a power source supplying the entire circuit.

Now I know that the entire circuit does work and is capable of powering the ShiftBar, and this is because when I load a new variation of my program into the board the entire circuit works and the ShiftBar is operating. This is mainly due to what I think is the Link drawing more current from the USB port during its loading process and exciting the ShiftBar. This is also preformed with the voltage regulator on or off.

From what if have calculated the maximum amount of current the circuit should draw should not exceed 600mA.

Components:
LPC1343 with LPC-Link detached
ShiftBar
Satellite Module 001
Voltage Regulator
Power Supply 9v @ 850mA

lpcware · ‎06-15-2016

Content originally posted in LPCWare by ralieghnet on Tue Jan 17 23:41:11 MST 2012
If that is the case then I wonder why when I just had the board connected to a 3.3v and no link attached the value was never set to a low. I had the port set to an output and a 0 for the value.

That makes sense why when the board was connected to the link why it would not work.

Thanks for the information. I will remember that for future projects.

Here is an image of the project that I'm working on. This will eventually go into a clear plastic case and be placed under a block of ice to be display outside during the winter here in Alaska.

lpcware · ‎06-15-2016

Content originally posted in LPCWare by NXP_USA on Mon Jan 16 17:24:57 MST 2012

Quote: ralieghnet
So I found something out. The enable line from the controller to the ShiftBar was never set to a off/low value upon start up. It was my impression that port and its bit is set low when power is first applied, or when the bit is set to a low. This never seams to take place. The port I'm using is 0 and the bit is 10.

I found this with taking measurements of the current required with each of the power variations. The total current draw in the system with one ShiftBar and Led set is 54mA

P0_10 is also used as the SWCLK which is used by LPCXpresso to debug the chip. P1_3 is also used, as SWDIO. Neither of these pins can be used while LPCXpresso is connected.

lpcware · ‎06-15-2016

Content originally posted in LPCWare by ralieghnet on Fri Jan 13 20:19:47 MST 2012
So I found something out. The enable line from the controller to the ShiftBar was never set to a off/low value upon start up. It was my impression that port and its bit is set low when power is first applied, or when the bit is set to a low. This never seams to take place. The port I'm using is 0 and the bit is 10.

I found this with taking measurements of the current required with each of the power variations. The total current draw in the system with one ShiftBar and Led set is 54mA

lpcware · ‎06-15-2016

Content originally posted in LPCWare by NXP_USA on Fri Jan 13 17:30:01 MST 2012
The 5V to 3.3V regulator on the LPC-Link has limited current capability and can't power much external circuitry. Make sure that you don't load down the 3.3V supply on the LPCXpresso board much. If you need more than a few 10s of mA of 3.3V, you will need to add an external 3.3V supply or a larger 5V to 3.3V regulator.

lpcware · ‎06-15-2016

Content originally posted in LPCWare by Ex-Zero on Fri Jan 13 16:15:20 MST 2012
Is it a semihosting project?

lpcware · ‎06-15-2016

Content originally posted in LPCWare by ralieghnet on Fri Jan 13 15:56:39 MST 2012
Basically when I use only the external power source the LPC1343 will not activate the ShiftBar. Or external with USB power not loading a program it still will not load the program.

If i use the external power source and USB while loading a program the ShiftBar will work.

lpcware · ‎06-15-2016

Content originally posted in LPCWare by OXO on Fri Jan 13 01:36:14 MST 2012

Quote: ralieghnet
Now I know that the entire circuit does work and is capable of powering the ShiftBar, and this is because when I load a new variation of my program into the board the entire circuit works and the ShiftBar is operating.

Sounds fine to me..

I don't understand what the configuration is when it doesn't work.