PSP LCD Part 1 – The hardware concept

Ok first things first, before i even try to code this puppy i want to make a basic idea of whats needed hardware and software wise.

To do this lets take a look at the datasheet.  (If link is down google: Sharp Datasheet LQ043T3DX02)

Okay scrolling through the datasheet we hit page 7 which has a pin-out of the device. As you can see it shows 40 pins.

And on page 8 the Backlight is an additional 4 pins.
Thats not all going to be on our main MCU/FPGA but just need to know info. The main pins for our controller will be all the data pins and perhaps a pin for the backlight control.

RED (8),  GREEN(8),  BLUE(8), CK (1), DISP(1), Hsync(1), Vsync(1) for a total of 28 + (1) Backlight Pin = 29 Pin will be controlled by our controller. So as you can see thats a ton. Dont worry about the meaning of these for now.

Things we know:
1) 40 Pin Connector is needed where 28 of these pins go to our controller
2) 4 Pin Connector is need for back light where 1 will be controlled (via transistor most likely)

Okay if you actually read the small print on page 7 you will see the connector type recommended… FH12A-40S-0.5SH(55)

We dont HAVE to use that connector if we dont want to but the datasheet has all the info we need to find similar ones.

From the above we can get the PITCH and PIN COUNT.. also we can see in the datasheet it says: “Top contact type”
We can now decode the connector to be: FH Series #12 , TOP CONTACT TYPE,  40 CONTACTS, SINGLE STANDARD, 0.5mm PITCH, HORIZONTAL, GOLD PLATED

The most important part of this for searching for a replacement is: Top Contact, 40 Contacts, 0.5mm Pitch, Horizontal(RIGHT)

The main reason i add this part is to save people money. The recommended connector cost about $3 each… thats a lot of dough for 1 piece of plastic smaller than my pinky.
You can also simply search there part number in MOUSER and on the bottom you get a option to show similar based on whats checked. I suggest unchecking the Manufacture and Other non important things like GOLD etc… I found this part which is $0.63: 62684-402100ALF

For the Backlight part its a bit harder. The only thing they give you is its a KYOCERA 6298 which if you google you will find its a 0.5mm part bottom contact… datasheet
The exact part number would be : 046298004000883 … which is weird as it is. So now that we know this lets mouser it and see how much… $2.21 EACH! OMG for something the size of my pinky NAIL 🙂 Guess what! I found this one for $0.25  10062827-0410EDLF see the difference? Save some money! or just buy more 😀 Mistakes happen you know.

So far we saved some money and can get both connectors for under $1 ($0.88)! You can buy 3-4 sets for the same price as 1 recommended part 🙂

Back to the LCD part now. This LCD runs on a few different voltages. Even tho it says 2.5v in the pin listing it can do 3.3v (says so on page 9).
Now we can eliminate the 2.5v with a single 3.3v. Now for the backlight… page 13 states the Backlight needs 29.4v @ 20mA MAX… now as we all know we dont have a 29v supply so we have to make a boot converter. I wont go into boost converters much here but will give you a nice link to my favorite calculator.

I thank goodness i found that link. It has helped me so many times. I will use it here to make a boost convertor for 3.3v to 29v with a max variation of 100mV since this can handle 29.4v i think 29.1v will be good. The max current needed is 20mA so lets design for that also.

This took me about 5 seconds to fill in and another 1 second to press the button 🙂 saved me time from doing calculations by hand:

Now we have a boost circuit to power our backlight also. We will just use a power mosfet or something to control the backligh on/off (gnd).

Ok thats about it for now. Keep checking back for: PSP LCD Part 2: Selecting a Controller & Schematic

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