LCD on Power on ?

Posted on April 23, 2014 at 09:13

It sounds like an initialization/reset problem.

I had similar issues with an Ethernet PHY that requires 160ms to reset out of power on. Not to say that network stack software was ready before that delay.

Now I take care to wait PHY initialization, and it works even ''the first time''.

What are your devices (CPU+LCD) ?

Posted on April 23, 2014 at 11:35

STM32F103VCT6 and the LCD is SSD1289, any ideas to fix it ?

so I don't have to push reset button everytime I start ( power on )

thanks

Posted on April 23, 2014 at 11:54

Check power lines vs data lines, make sure power is established before programming.

Make sure you met delay requirement during the initialization of the display.

Add a test mode to restart the display init on a button press, and see if it fixes ''manually'' the problem.

Try to read status during/after the init, so you can compare it in both case (first/next).

Once you will identify the real cause of your problem, fix it properly or ask for more help.

Posted on June 09, 2014 at 01:42

I put delay after LCD init, it's still the same, I must push reset button to start.

I have checked all the power lines and all the bypass capasitor are ok.

Other factors to consider ?

Posted on June 09, 2014 at 02:04

Then you really need to think about the nature of the failure, and if you can detect whether the display has started properly or not.

I would suggestion you do some reading/writing of the SSD's registers and video memory, and compare the functionality between the cases where it doesn't start properly, and those where it does.

So far you haven't really presented any information that's helpful for remotely debugging the situation.

Things to consider :

a) Is the FSMC correctly configured and functional

b) Is the SSD chip responsive to commands and interactions

c) Are the the registers in the SSD chip set up correctly, and in the right order

Posted on June 09, 2014 at 09:30

Put the delay *before* initialization, just to make sure power is well established and internal reset done.

I had an issue with an Ethernet PHY that required 160ms to perform internal reset at power up (on F429-EVAL1), which was in this case 3 or 4 times the amout of time required to boot. Ethernet only worked after at least one manual reset.