LCD-Troubles / All Blocks on / KS0066 / MIOS32 / and.. hello

[hns]

Hi there.

First of all: Yes i used the Search-Function on the Forum, yes it is my first Midibox project, and yes im probably a moron.

So please dont flame me off the internets within seconds.. (Oh: and hello earthlings and thanks for all the midi)

So here is my problem: i have a STM32 core connected to a Analog Vision 2x16 Character Display (AV1624YFBY-SJ, KS0066 driver).

When i power up the board, i only get two rows of "all-on-pixels". The first row is a little darker than the second, and i can control

the contrast with the trimmer. When i have Vo of 0V the display seems more or less normal showing all character-pixel-grids-whatever fully lit. (those 2x16 things where the characters should show up)

I have connected the Backlight to B+ and B-, and it is glowing nicely in green. (more about the backlight later)

Contrast and Brightness seems working fine. (except that the contrast turns down the second row first and then the first row)

I have triple checked the wires. looks good. All the Tutorial-Apps i upload work as expected (as long they dont use the lcd)

Sadly the ../tutorials/020-lcd thing does nothing.

I've checked the timing and initialisation stuff in app_lcd.c. looks good as far i can tell.

So: Im stuck.

If anyone could help me a little i would be very happy.

And thanks for that very nice piece of hardware..

Hns

P.S: i was unable to get a connection to the board from my mac, when B+/B- was connected to the LCD. So i desolderd them to lower the current from the usb plug. No

backlight at the moment.

P.P.S: sorry for my translate.google style english. what a surprise, i am not native english speaking. mea cupla..

lcd.pdf

Edited January 29, 2010 by hns

[philetaylor]

Hi.

That sounds to me like the display has power but has not been initialized yet.

The KS0066 should be compatible with the HD44780 which the MIOS32 clcd driver was designed for so it should work fine. When you compile the 020-lcd tutorial, what do you have MIOS32_LCD set to? This MUST be "clcd" for the driver to work.

If it is not that then I would check your wiring for a fourth time! I assume you have the LCD connected to J15A NOT J15B. All of the names on the datasheet that you attached match the J15 names so you should be difficult to make a mistake but it is worth checking again!

As you have already discovered, powering a CORE32 from USB while an LCD backlight which draws ~200mA is also connected is not a good idea, I would use external power!

FYI The CORE32->CLCD wiring diagram is here

Thanks

Phil

[hns]

Hi Phil, thanks for your reply.

jup, when i compile the 020-lcd tutorial it uses the clcd driver. i even packed a #error directive into clcd/app_lcd.c just to see if it

uses the right code.

i've connected the lcd to J15A. And i used exactly the schematics you pointed out to wire everything together.

i had some troubles to map the lines from the connector to the lcd because the pin layout on the lcd ist 15 16 1 2 .. and so on..

so its worth to check the wires a forth or even fifth time..

I'll try this tomorrow.

What still toubles me is that the contrast poti is not working on both rows the same way. as i told, the first row is dimmed lesser than the second.

is this normal when the display is not initialized?

Regards and thanks again,

more when i checked the wires the fifth time.

hns

[lylehaze]

Hi Phil, thanks for your reply.

jup, when i compile the 020-lcd tutorial it uses the clcd driver. i even packed a #error directive into clcd/app_lcd.c just to see if it

uses the right code.

i've connected the lcd to J15A. And i used exactly the schematics you pointed out to wire everything together.

i had some troubles to map the lines from the connector to the lcd because the pin layout on the lcd ist 15 16 1 2 .. and so on..

so its worth to check the wires a forth or even fifth time..

I'll try this tomorrow.

What still toubles me is that the contrast poti is not working on both rows the same way. as i told, the first row is dimmed lesser than the second.

is this normal when the display is not initialized?

Regards and thanks again,

more when i checked the wires the fifth time.

hns

How odd.. The pinout of your display, from left to right in the drawing.

14,13,12,11,10,9,8,7,6,5,4,3,2,1,16,15

I LOVE it when they keep it simple!!

I'm assuming you have seen that already, or you would not have good power and contrast.

Yes, one row of blocks is normal for an uninitialized display.

I'd get off the USB power until you get this sorted, if you have another supply available.

Good Luck,

LyleHaze

[hns]

thanks again.. the problem is solved now

As i said in my first post: im probably a moron. Now i know for shure.

In my package the 3.3V regualtor was missing, so i soldered the IC6 in place of IC7 by mistake. Stupid me..

Im happy i did not fry anything.

After changing the regulator (i had the right one in the second package. thats why i allways buy two sets)

the lcd tutorial runs as expected.

How odd.. The pinout of your display, from left to right in the drawing.

14,13,12,11,10,9,8,7,6,5,4,3,2,1,16,15

I LOVE it when they keep it simple!!

Jup, was fun to build the cable as i had to cross pairs of wires for every two pins. stupid layout.

I'd get off the USB power until you get this sorted, if you have another supply available.

Good point. Thanks..

i found out about the missing IC6 while soldering the external power stuff twogether.

Regards

Hns

P.S: i quite shure, my next question will be posted soon.

Edited January 30, 2010 by hns

[philetaylor]

Yes that will do it! luckilly feeding 5v (from USB) into a 7805 will probably give you about 3.5-3.7v out so it shouldn't kill the STM32 but a stable 3.3v is really needed!

Good to hear that all is well.

Cheers

Phil