Using iCEstick FPGA to Convert Fluke Scopemeter 123 LCD to 320x240 Color Display

Anyone planning on trying to use the iCEstick FPGA deployment board as in EPE article in the May edition where there is a VGA adapter project

This got me thinking that it might be the solution to my failing Fluke Scopemeter 123 display. This has an obsolete 240 x 240 70Hz monochrome LCD so I was trying to buy a standard 320 x 240 colour display, which are v cheap, and converting the serial data stream from the scope’s processor into say a I2C stream for the new display. I worked out a possible way to do it using one or two PICs, but even with the very fastest ones could not work out how to read the incoming data, store it in an array or video RAM that mapped the pixels and output it to the new display in time to read the next set of data.

With a FPGA though the article tells me they are super fast so they should be no speed limitation.

Downsides I see are:

1) I am a newbie at this so is it realistic to be able to take this VGA converter and work out how to modify it to do what I want. I can manage Flowcode and a little C code but that is it.

2) The PICs could just fit in the scope. No way will this ICE stick fit so either I have to mount it externally which rather defeats having a nice portable unit. Or I have to work out how to programme a loose FPGA with the code and mount that in the scope. The article does not say how to programme loose chips.

The scope’s output is a clock to synch the display’s’ column and row ICs with a train of 4 bits words, each of which provides the on/off command for one pixel on one row. So 4 rows are output at once. Another clock indicates the end of the frame. With the FPGA I guess I would fill 4 areas of RAM with the 4 x 220 pixels of row info.

Ideally I’d stretch the data to make 220 pixels stretch to say 330 to nearly fill the width of the new display.

Is there a forum dedicated to this sort of FPGA programming?

Hi Edward,for sure using a FPGA would be a challenging but very interesting solution. I agree it would meet the timing requirements for driving your display refreshing the image at the desired frame rate. The FPGA can be programmed in Verilog (which is quite similar to C), even though plain VHDL would be the right choice, in my opinion. It requires a little bit of effort, but gives more satisfaction and code can be more easilt ported to other platform.You can find several examples on the web, I just give you a couple of them:https://www.fpga4fun.com/PongGame.html
http://blog.andyselle.com/2014/11/24/basic-vga-on-an-fpga/
I don't know which version of PIC are you using, but, besides FPGAs, there are several very fast MCUs and SoCs you can use. The ESP32, for example, is cheap and fast, and it has a library for driving VGA interface:https://www.hackster.io/news/fabgl-turns-your-esp32-into-a-vga-gaming-platform-c7c1f2fe0d19
Best regards,Paul

Many thanks for answer. I guess I could download the IceStudio
software and VGA project  and try to change
it to develop my project without having to actually buy the FPGA adapter. Then
if I find it all too difficult I will not have any expenditure, assuming the software
runs without an ICEstick attached.

 Even with a 64MHz 16 bit PIC I could not get it fast enough
so I don’t things alternative processors would be any more successful That unless
it is effectively dual core with one half doing the say video RAM handling with the
other reading the incoming data. This is what I was trying to do using 2 PICs
but I gave up. A clever use of interrupts  or a more experienced coder than me would probably manage it. The design is rather complicated
by the 4 bit input so have to fill the RAM for 4 lines at a time but read out
one line at a time for the new display. One possible solution involved a display
without a full controller chip so instead of an I2C feed I feed the raw rows
and columns with serial streams like on the old display. I guess it something like:

 I2C: put a black dot in pixel A, a, put a white pixel in A, b.
Etc until all pixels done. Restart when end of frame pulse received. The controller
sorts out driving the rows and columns.

 Raw controller: enable row A, turn on column a. Turn on row
A, don’t turn on column b. Etc till end of row, then read the next horizontal
synch pulse input and start next row when it arrives.

 So the second version is much more dependent on the synch
pulses.

 An error in my previous post. It is a 220 x 220 display.

 PS is there away to get notified when people answer a post here that one is following or has initiated? Can’t find that setting.

Yeah using FPGA will be a challenging one.monochrome LCD? Interesting . sounds good.Is VGA same as HDMI? send me tutorials for Ice Studio software ?