Peripheral Devices That I have but Don't know how to use. Help Please.

What about the wiring above?  Is it good?

it doesn't have any obvious flaws.

I'm not qualified to find any subtle flaws.

Fergus Byrne wrote:

 

Bit of a mess but here is a schematic of what I have wired up.  Last night, I had power going into the DP and a little light came on but today that is not happening.  Have I blown the chip?

I don't see any current limiting resistors in your diagram.  Typical LEDs use 1.6V (red) to 2.4V (green).  If you put 3.3V across them without current limiting they will emit a lot of light -- once.  Then they'll be DED.  Driving one directly from a RasPi BCM2835 output without current limit could also damage the BCM2835 output.

I just checked Wikipedia.  They have a thorough article on LEDs and also one that shows how to power an LED using a current limiting resistor and how to calculate its value.  Typical values are 150 Ohm to 1K Ohm depending on the driver voltage, the LED's efficiency and how bright you want it to be.

So you think I have "blown the bolb" on the 7 segment display?  If so, that would mean that the IC is still in place and I can get up and running when I get a new 7 segment dispaly...Right?

Fergus Byrne wrote:

 

So you think I have "blown the bolb" on the 7 segment display?  If so, that would mean that the IC is still in place and I can get up and running when I get a new 7 segment dispaly...Right?

You've probably only destroyed the DP LED.  If you didn't see a bright flash from the other segments, they're probably still intact.  It all depends on what the CD4511 DCBA inputs were when you powered it on.  If DCBA are 1010 through 1111 then outputs a-g are low and the LEDs aren't driven.  With the CD4511 disconnected, try powerering each LED segment from +3.3V through a 150-300 Ohm resistor and see which ones still light up.

You could test your display by using the diode test setting on a multimeter.

If your meter is digital, the negative lead goes to the CC connection and then one by one place the positive lead on the segment pins, each segment will light. Possibly very faintly, depends on the actual display involved.

If your meter is an analogue one (it has a needle meter), then you might need to reverse the connections above. The meter is unlikely to give more than 2v and will be low current.

Will look into it when I get back from holidays.  Thanks for responce.

Ok,

I have done a bit of research into the touch screen display that I mentioned at the start of this topic, and found this: 

http://beyondinfinite.com/lcd/Library/Samsung/LTE400WQ-F02.pdf

This is the data sheet for the LTE400WQ-F02.  It looks exactly the same as the connector on my one though...  I did a bit of a dumby check.  The GNDs and DNC and VCC all match up which is pritty good.

Can anyone suggest a converter (either home made or other wise) that can turn this into a touch screen that can be written to by serial/UART/SPI  ??

Right now, It seems I would have to connect all the R0 - G7 which I cannot do on the raspberry pi (not enough connectors).

Let me know what you think.

Hi Cian,

There are a few ways to use the display, but sadly all are non-trivial or complicated ; -(

Most of these types of display require an off-board device for refreshing the display repeatedly with

the right data. Epson make some SMD devices to interface to some LCD displays, but I'm not sure

if they have a device available in individual quantities to handle this sized display.

Also, most of these types of display have some slight difference in timing or logic levels from one

part number to another, so some of Epson's controllers have registers that you can set to interface correctly.

Another way is to use your own logic and external RAM, and this could be implemented with a

CPLD and RAM (or FPGA), but it may be a lot of work but rewarding. Also, it is possible to dedicate

some high-speed microcontroller to this, but it will consume lots of logic pins. It is inefficient, but may be the easiest

way. Finally, you could also get ideas from here. It is slow loading for me, not sure why, but I think it

uses one of these methods described.

Thanks for reply.

Just had a look at the page linked above...

unfortunatly, the display I have has a 50pin connector not a 40 pin...

I will keep looking into your other suggestions.