LPCXpresso IDEのトピックProblem at power up

Problem at power up

lpcware — Wed, 15 Jun 2016 22:58:53 GMT

Content originally posted in LPCWare by emimad on Fri Dec 25 16:26:59 MST 2015
Hi all!
I'm having a problem with power on LPCXpresso board.
I flash the code for and LCD and it runs OK but if remove USB cable, the LCD doesn't works again.
After flashing, I can reset with P0_0 and LCD works fine. The problem is when remove USB.

I'm using next pins for LCD communication:
P0_6, P0_10, P1_13, P1_14, P1_15 and control LCD power with P0_20.

I think is better view that with a video:
https://youtu.be/GXMBkYlaYGc

Re: Problem at power up

lpcware — Wed, 15 Jun 2016 22:58:54 GMT

Content originally posted in LPCWare by Powerfreak on Sat Dec 26 06:29:46 MST 2015
Hi,
please do recheck the complete power supply for your project, and ensure that your PCB is completely supplied by an indepenent power supply and not influenced by a powerloss at USB. Maybe some 100 µF as supply-buffer would help.

Re: Problem at power up

lpcware — Wed, 15 Jun 2016 22:58:55 GMT

Content originally posted in LPCWare by serge on Mon Jan 04 03:24:34 MST 2016
Could it be that your display is still doing its internal reset while your board is already sending commands?
Do you respect power up sequence for your display?
Does your display has a busy bit? do you read it in your code?
Because the difference between first flashing (display has more time to startup) and immediatly starting with a power up can almost only be a timing issue.

I don't know if this is realy the case. To be sure i need to see the datasheet of the display.

Re: Problem at power up

lpcware — Wed, 15 Jun 2016 22:58:56 GMT

Content originally posted in LPCWare by emimad on Thu Jan 07 02:41:00 MST 2016
Hi all!
I'd tried with 470uF capacitor but the problem persist.
The LCD is a ST7565 chip based: http://www.lcd-module.de/eng/pdf/zubehoer/st7565r.pdf
I configure pins as OUTPUT, then put them LOW and then enable LCD power. What datasheet says.

Re: Problem at power up

lpcware — Wed, 15 Jun 2016 22:58:56 GMT

Content originally posted in LPCWare by R2D2 on Thu Jan 07 03:36:28 MST 2016

Quote: emimad
Hi all!
I'd tried with 470uF capacitor but the problem persist.

That's usually a software problem, as Serge already told you ;-)

So check your Initialization code (especially /RES timing)...

Re: Problem at power up

lpcware — Wed, 15 Jun 2016 22:58:57 GMT

Content originally posted in LPCWare by serge on Thu Jan 07 05:50:12 MST 2016
In the datasheet is mentioned that after releasing the reset state you should wait till the reset circuit finished (<1ms). So after releasing the reset line of the display you should wait 1ms before sending commands to the display.
Furthermore the display provides also a busy bit (The busyflag is outputted to D7 pin with the read instruction)
This flag should be checked while initialising the lcd. Some commands need time to complete.

Please confirm that you complied with these timings.

Re: Problem at power up

lpcware — Wed, 15 Jun 2016 22:58:57 GMT

Content originally posted in LPCWare by emimad on Thu Jan 28 07:47:37 MST 2016
Thanks for your answers, guys!

I think isn't a configuration problem because I just make this test:
- Program the LPC -> LCD works
- Disconnect all pins of the LCD, including VCC. Then connect them again. After that, do a reset -> LCD works

The problem is:
- Program the LPC -> LCD is working
- Disconnect USB cable from debugger side. Then connect it again -> LCD doens't works. Do a reset, LCD still not working.

So, what's the difference between start the program with USB power from debugger side and power it from external power supply? :~

Re: Problem at power up

lpcware — Wed, 15 Jun 2016 22:58:58 GMT

Content originally posted in LPCWare by drobe011 on Thu Jan 28 19:31:24 MST 2016
Try adding this preprocessor definition if you don't already have it.

STARTUP_FROM_RESET

-Dave

Re: Problem at power up

lpcware — Wed, 15 Jun 2016 22:58:59 GMT

Content originally posted in LPCWare by R2D2 on Thu Jan 28 22:56:57 MST 2016

Quote: drobe011
Try adding this preprocessor definition if you don't already have it.
STARTUP_FROM_RESET

:quest:

Are we talking about Crossworks ?

Re: Problem at power up

lpcware — Wed, 15 Jun 2016 22:58:59 GMT

Content originally posted in LPCWare by emimad on Fri Jan 29 00:43:31 MST 2016
No, I'm using a LPCXpresso 1347 board: https://youtu.be/GXMBkYlaYGc

Re: Problem at power up

lpcware — Wed, 15 Jun 2016 22:59:00 GMT

Content originally posted in LPCWare by drobe011 on Fri Jan 29 06:05:05 MST 2016
My bad. Did sound similar to many crossworks' users issues with start up without the debugger. (I use standalone LPCs and LPCXpresso boards with CW).

The only power on issue I have had using lpcxpresso and the LPCXresso1347 was (i think) accidentally holding PIO0_1 low during reset.

Some displays are finicky about timing during the start up sequence. Maybe the debugger adds some inadvertent delay that works to your benefit and then is not there without the debugger.

Probably best advice I can give you is not to listen to my advice...

-Dave

Re: Problem at power up

lpcware — Wed, 15 Jun 2016 22:59:00 GMT

Content originally posted in LPCWare by emimad on Wed Feb 17 07:48:32 MST 2016
IT WORKS!!! :O

I've been using some pins with SWD functions... the problems was not to inicialize them correctly. Just add this lines at the start of the program:

    Chip_IOCON_PinMux(LPC_IOCON, 0, 20, IOCON_MODE_INACT, FUNC0 );
    Chip_IOCON_PinMux(LPC_IOCON, 0, 6, IOCON_MODE_INACT, FUNC0 );
    Chip_IOCON_PinMux(LPC_IOCON, 0, 10, IOCON_MODE_INACT, FUNC1 );
    Chip_IOCON_PinMux(LPC_IOCON, 1, 13, IOCON_MODE_INACT, FUNC0 );
    Chip_IOCON_PinMux(LPC_IOCON, 1, 14, IOCON_MODE_INACT, FUNC0 );
    Chip_IOCON_PinMux(LPC_IOCON, 1, 15, IOCON_MODE_INACT, FUNC0 );

A simply rookie mistake 8-)