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Does anyone have information on where I might get a free (or very low cost) CRT core? I am looking for text only, 25 lines of 80 chars. On the surface the design seems simple enough but if it has already been done there is not much point in doing it again. I have some space left in my Spartan IIE with the T80 core running CP/M. I might as well fill it up and drive a VGA monitor instead of a physical terminal or something like Hyperterminal. I would also add a keyboard interface. Thanks! |
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Simple Character CRT Core Needed
Started by ●August 30, 2004
Reply by ●August 30, 20042004-08-30
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At 07:14 PM 8/30/2004, you wrote: >Does anyone have information on where I might get a free (or very >low cost) CRT core? I am looking for text only, 25 lines of 80 >chars. On the surface the design seems simple enough but if it has >already been done there is not much point in doing it again. > >I have some space left in my Spartan IIE with the T80 core running >CP/M. I might as well fill it up and drive a VGA monitor instead of >a physical terminal or something like Hyperterminal. I would also >add a keyboard interface. > >Thanks! Try opencores.org, they have a number of cores and one is a video controller. http://www.opencores.org/projects.cgi/web/vga_lcd If you only need text, you might be better off designing your own and saving the logic. An 80x25 text display is very, very simple and should not take much time to design. If you want, I might do it as an exercise. :) Be aware that VGA uses ADC converters to drive the three colors. You can kludge the interface from a digital output like this... http://www.fpga4fun.com/PongGame.html This sort of thing can give you up to 8 colors which is plenty for a text display. You can also add a few more resistors (and outputs) and have three or four levels on each output which can give you up to 64 colors. Much beyond that and you will likely see problems with quality. Rick Collins Arius - A Signal Processing Solutions Company Specializing in DSP and FPGA design http://www.arius.com 4 King Ave 301-682-7772 Voice Frederick, MD 21701-3110 301-682-7666 FAX |
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Reply by ●August 31, 20042004-08-31
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Hi All, It might be worth looking at the www.ExpressIP.co.uk web site as they give away a free VGA graphics controller that can also work on a TV as well. It works with our PS2 mouse (or other device) controller. It has a font rendering engine included. You also get an SDRAM controller (high performance) DMA engine, risc cpu (16 bit with i / d cache, c- compiler etc), RS232 + other cores WEB : www.ExpressIP.co.uk Thanks Lee ----- Original Message ----- From: "rtstofer" <> To: <> Sent: Tuesday, August 31, 2004 12:14 AM Subject: [fpga-cpu] Simple Character CRT Core Needed > > Does anyone have information on where I might get a free (or very > low cost) CRT core? I am looking for text only, 25 lines of 80 > chars. On the surface the design seems simple enough but if it has > already been done there is not much point in doing it again. > > I have some space left in my Spartan IIE with the T80 core running > CP/M. I might as well fill it up and drive a VGA monitor instead of > a physical terminal or something like Hyperterminal. I would also > add a keyboard interface. > > Thanks! > To post a message, send it to: > To unsubscribe, send a blank message to: > Yahoo! Groups Links |
Reply by ●August 31, 20042004-08-31
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Hi, There is a simple 64 x 32 text character display in my System09 SOC. It should be portable to the T80. Getting 25 x 80 characters would need a bit more work mapping the row and column address. http://members.optushome.com.au/jekent/system09/index.html (Look at the bottom of the page) It uses a 25MHz Pixel Clock and makes use of the Block RAM (if I remember correctly) for the Text buffer, Colour Attribute buffer and character generator. It supports 4 bits of forground colour and 4 bits of background colour. It has 4 registers: Cursor Row Address, Cursor Colum Address, Text Character Colour Attribute. To Move the cursor you increment the column address to write a character, you set up the colour Atribute and write an ASCII character to the Text Character Register. It's very basic and does not do anything like clearing the bottom line on line feeds ... you have to do that in software. It was designed for Tony Burch's FPGA board. I've also written the open cores P/S 2 keyboard in VHDL. (It was in Verilog). That's availaible in System09 too. John. rtstofer wrote: >Does anyone have information on where I might get a free (or very >low cost) CRT core? I am looking for text only, 25 lines of 80 >chars. On the surface the design seems simple enough but if it has >already been done there is not much point in doing it again. > >I have some space left in my Spartan IIE with the T80 core running >CP/M. I might as well fill it up and drive a VGA monitor instead of >a physical terminal or something like Hyperterminal. I would also >add a keyboard interface. > >Thanks! > -- http://members.optushome.com.au/jekent |
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Reply by ●August 31, 20042004-08-31
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I stand corrected, 5 registers. It also has a Row offset register for scrolling the screen J. John Kent wrote: >Cursor Row Address, >Cursor Colum Address, >Text Character >Colour Attribute. -- http://members.optushome.com.au/jekent |
Reply by ●August 31, 20042004-08-31
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Thanks! I'll give it a look. I am using Tony Burch's board as well. The ExpressIP site is pretty useful as well. They have a lot of IP stuff to go with their board. --- In , John Kent <jekent@o...> wrote: > Hi, > > There is a simple 64 x 32 text character display in my System09 SOC. > It should be portable to the T80. > Getting 25 x 80 characters would need a bit more work mapping > the row and column address. > > http://members.optushome.com.au/jekent/system09/index.html > (Look at the bottom of the page) > > It uses a 25MHz Pixel Clock and makes use of the Block RAM > (if I remember correctly) for the Text buffer, Colour Attribute buffer > and character generator. It supports 4 bits of forground colour and > 4 bits of background colour. > > It has 4 registers: > > Cursor Row Address, > Cursor Colum Address, > Text Character > Colour Attribute. > > To Move the cursor you increment the column address > to write a character, you set up the colour Atribute and write an > ASCII character to the Text Character Register. > It's very basic and does not do anything like clearing the bottom > line on line feeds ... you have to do that in software. > > It was designed for Tony Burch's FPGA board. > > I've also written the open cores P/S 2 keyboard in VHDL. > (It was in Verilog). That's availaible in System09 too. > > John. > rtstofer wrote: > > >Does anyone have information on where I might get a free (or very > >low cost) CRT core? I am looking for text only, 25 lines of 80 > >chars. On the surface the design seems simple enough but if it has > >already been done there is not much point in doing it again. > > > >I have some space left in my Spartan IIE with the T80 core running > >CP/M. I might as well fill it up and drive a VGA monitor instead of > >a physical terminal or something like Hyperterminal. I would also > >add a keyboard interface. > > > >Thanks! > > > > > > > -- > http://members.optushome.com.au/jekent |
Reply by ●August 31, 20042004-08-31
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I had seen the listing at opencores and it seemed far too complex. At the moment I think I just want 80x25 but it also needs to do the control codes for a TV950 or ADM3a (switchable?) as some of the old software is configured and I can't seem to get it to change - Turbo Pascal and its TINST for example. I don't know why I can't get it to work but I think it has something to do with an error in the download. I had a large Fortran program that wouldn't run until I downloaded the compiler/linker and recompiled on the target. Curious... Well, I haven't used these programs in 20 years so it's possible I have forgotten some of the details. I bought the Xilinx Spartan-3 Starter Kit the other day (what a bargain for $100) and started to play with it last night. What do you know? There's a reason for the VGA connector on the board - there is a text mode VGA component included and it is ready to rock and roll. There's a ton of stuff that comes with this kit and, although a little small at 200k gates, $100 is not much tuition these days. --- In , Arius - Rick Collins <dsprelated@a...> wrote: > At 07:14 PM 8/30/2004, you wrote: > > >Does anyone have information on where I might get a free (or very > >low cost) CRT core? I am looking for text only, 25 lines of 80 > >chars. On the surface the design seems simple enough but if it has > >already been done there is not much point in doing it again. > > > >I have some space left in my Spartan IIE with the T80 core running > >CP/M. I might as well fill it up and drive a VGA monitor instead of > >a physical terminal or something like Hyperterminal. I would also > >add a keyboard interface. > > > >Thanks! > Try opencores.org, they have a number of cores and one is a video controller. > > http://www.opencores.org/projects.cgi/web/vga_lcd > > If you only need text, you might be better off designing your own and > saving the logic. An 80x25 text display is very, very simple and should > not take much time to design. If you want, I might do it as an exercise. :) > > Be aware that VGA uses ADC converters to drive the three colors. You can > kludge the interface from a digital output like this... > > http://www.fpga4fun.com/PongGame.html > > This sort of thing can give you up to 8 colors which is plenty for a text > display. You can also add a few more resistors (and outputs) and have > three or four levels on each output which can give you up to 64 > colors. Much beyond that and you will likely see problems with quality. > Rick Collins > > rick.collins@a... > > Arius - A Signal Processing Solutions Company > Specializing in DSP and FPGA design http://www.arius.com > 4 King Ave 301-682-7772 Voice > Frederick, MD 21701-3110 301-682-7666 FAX |
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Reply by ●August 31, 20042004-08-31
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At 02:32 PM 8/31/2004, you wrote:
>I had seen the listing at opencores and it seemed
far too complex. >At the moment I think I just want 80x25 but it also needs to do the >control codes for a TV950 or ADM3a (switchable?) as some of the old >software is configured and I can't seem to get it to change - Turbo >Pascal and its TINST for example. I don't know why I can't get it >to work but I think it has something to do with an error in the >download. I had a large Fortran program that wouldn't run until I >downloaded the compiler/linker and recompiled on the target. >Curious... Well, I haven't used these programs in 20 years so it's >possible I have forgotten some of the details. > >I bought the Xilinx Spartan-3 Starter Kit the other day (what a >bargain for $100) and started to play with it last night. What do >you know? There's a reason for the VGA connector on the board - >there is a text mode VGA component included and it is ready to rock >and roll. There's a ton of stuff that comes with this kit and, >although a little small at 200k gates, $100 is not much tuition >these days. I guess you could do the full terminal emulation in hardware, but that is normally done in software with the basic memory to raster conversion done in hardware. The software writes the appropriate characters to the display memory according to the commands that are received. Perhaps I am misunderstanding what your CRT is doing. I was assuming that you wanted a computer console CRT controller like the VGA card in a PC. Is this instead intended to be a terminal emulation as if it had a serial connection to the CPU? In that case, you can implement the terminal commands in hardware, but that is very different from a CRT controller, which is what I was pointing you to. I have a VHDL UART emulation for a board that plugs into a PC/104 bus (same as the PC ISA). The CPU thinks it is talking to a UART connected via a serial port to another device (my board). But this requires much of the work to be done in a CPU (which is also in the FPGA). If you are designing a terminal emulation, this is similar to what you would need. Rick Collins Arius - A Signal Processing Solutions Company Specializing in DSP and FPGA design http://www.arius.com 4 King Ave 301-682-7772 Voice Frederick, MD 21701-3110 301-682-7666 FAX |
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Reply by ●September 1, 20042004-09-01
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heres a verilog uart you can strip it down and simplify it by finding the Tx and Rx state machines and making use of them descretely.... Peace http://ca.geocities.com/artiedc/files/UartZip.zip Ed Corter Resume Page http://www.geocities.com/artiedc/ --------------------------------- |
Reply by ●September 1, 20042004-09-01
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Hi, If you want to squeeze the VDU on with the T80, but want to have intelligence in the video display, you might consider cobbling the VDU in with a small micro like my Micro8/8a and write the video driver in the Micro8. If you have the Xilinx Spartan3 starter board as well as Tony's board, it sounds like you could just about have an intelligent T80 based VDU on the starter board. The Starter board looks great by the way... I was inspired to make inquiries at my local Xilinx agent today. Anyway ... Have a look around my web site: http://members.optushome.com.au/jekent/FPGA.htm The ADM3a was pretty basic ... I think it just honoured the basic control characters and had an addressable cursor command. it should not be too hard to write an intellegent VDU driver for it if you know what the command set it. I have some video drivers for a Thomas VDU written for the 6800. You can fit my 6800 with UART in a XSA100 (100Kgate FPGA) so you should be able to fit it comfortably on a 200Kgate Spartan 3 with a VDU. John. rtstofer wrote: >I had seen the listing at opencores and it seemed far too complex. >At the moment I think I just want 80x25 but it also needs to do the >control codes for a TV950 or ADM3a (switchable?) as some of the old >software is configured and I can't seem to get it to change - Turbo >Pascal and its TINST for example. I don't know why I can't get it >to work but I think it has something to do with an error in the >download. I had a large Fortran program that wouldn't run until I >downloaded the compiler/linker and recompiled on the target. >Curious... Well, I haven't used these programs in 20 years so it's >possible I have forgotten some of the details. > >I bought the Xilinx Spartan-3 Starter Kit the other day (what a >bargain for $100) and started to play with it last night. What do >you know? There's a reason for the VGA connector on the board - >there is a text mode VGA component included and it is ready to rock >and roll. There's a ton of stuff that comes with this kit and, >although a little small at 200k gates, $100 is not much tuition >these days. > -- http://members.optushome.com.au/jekent |
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