320x200 or 320x240 Monochrome Text/Graphics Generator

[BigEd]

Does this $29 monochrome 5V-only 128x64 pixel display look useful?
http://www.pjrc.com/store/dev_display_128x64.html
(Looks like it's used by transferring a frame buffer over an 8-bit bus interface. The supplied library is for 8051. Might need to know more about how to drive it.)

[8BIT]

It would help to have a part number, but I did make a quick check of a similar display. This could be adapted to my driver easily enough.

My only concern would be the limited amount of text that could be displayed. Would this be useful as a primary display, or just for status and messaging?

Daryl

[BigEd]

Looking at it as 16x8 sets of 8x8 tiles, or 21x8 of 6x8, it has at least got more text area than some cheap two-line smart LCD displays. You're right that it's not a lot of text area!

[8BIT]

8BIT wrote:

I am considering resurrecting this project and have found an LCD module that might fit the bill.

It is a 5.7” display with LED backlighting and the -28v generator is built-in. That means that the whole thing can be powered from a single 5v supply.

Data and sample photo can be seen here: http://www.vslcd.com/Products/1016.htm

The cost is ~$60 each for 10 units. However, shipping from Hong Kong was quoted at $90 for 10 units, bringing the cost per unit to $69. On top of that, there is about $30 for the AVR driver/interface board.

I finally got around to playing with that new LCD. So far, it works well. I like having to only feed it a 5v power supply. It also has three input connectors: two are thin film pcb-type sockets, and the third is just 16 holes that allow easy soldering of standard IDC ribbon cable.

I will have to create a demo program that I can use to show off all the features of the interface.

More to follow in a few weeks.

Daryl

[Dajgoro]

Does the display have a framebuffer, or do you have to consciously feed the picture?
Isn't 60$ for such a device a bit too much?
Looking at ebay, there are much better modules for 3x lower price:
http://www.ebay.com/itm/Brand-New-HannS ... 27c18568db

[8BIT]

You are right - $60 is a lot. It does not have a frame buffer, the AVR feeds the display.

I have $19 LCD but that one requires a -28v drive voltage and a 300vac CCFL drive. The benefits of this display is that it only requires +5v. I will however keep looking for a cheaper +5v only LCD. The alternative is to just drive a composite display, be it LCD or otherwise. Having a direct-drive LCD provides a clearer picture.

I also have a small, 5" color LCD that has NTSC composite video input that I use with my SBC-3. I got it for $25 but cannot find it a that price any more. It is a Zenith LCD that was designed for the XBox.

The LCD you referenced from ebay looks like it supports composite video. I did not look to see if a datasheet was available for it. It might work on composite mode.

Daryl

[Dajgoro]

8BIT wrote:

The LCD you referenced from ebay looks like it supports composite video. I did not look to see if a datasheet was available for it. It might work on composite mode.

Daryl

OUCH, i missed that part where it mentioned composite input.
I spent like 35$ for a used color lcd tv for my sbc and my raspberry pi, since the minitv that i already have is black and white. And guess what, the moder lcd tv has less sharpness that the old b/w mini crt, so reading text is impossible.

As mentioned in another topic, i am thinking about building a video display board with a mcu that would have a framebuffer and colors, but i still need to find a way to make it compact.
A 8051-like mcu would do the trick, since the 8051 has that external ram port, so it can quickly access a big framebuffer.

[Dajgoro]

The AT89s52 might do the trick, but i can't find how much mips does it have, or that would be how much clock cycles per instruction.

[8BIT]

Dajgoro wrote:

As mentioned in another topic, i am thinking about building a video display board with a mcu that would have a framebuffer and colors, but i still need to find a way to make it compact.
A 8051-like mcu would do the trick, since the 8051 has that external ram port, so it can quickly access a big framebuffer.

The Core of my SBC-3 fit on a 2.5"x3.8" PCB and it had a 320x200 color display. It used 8 bits per pixel, which results in 64,000 bytes per frame. It used a 65816, XC95108 CPLD, 32kx8 EEPROM, and 512kx8 SRAM. The CPLD did all of the video timing, with the 8-bit pixel data going to a resistor ladder DAC and then feeding a AD724 to generate the Composite color signal (NTSC or PAL). The AD724 also has an S video output. Since the CPLD used the low PHI2 half cycle, the 65816 ran at full speed. You could program the 65816 to do all of the text generation, along with a full library of graphics routines which your host could call upon. You would have up to 7 frame buffers with the 512k SRAM as well. The animated US flag was done by cycling through the 7 buffers. An interface to the host would come through the CPLD as well. The only downside is the cost. Those parts are kind of expensive.

A photo of the core is at the bottom of this page:
http://sbc.rictor.org/pics3.html

The outline is also present on the main SBC-3 board. Draw a vertical line just left of the 65816 and a horizontal line just under the ground trace below the resistor DAC, and the upper right section is the core.

If this interests you, let me know and we can discuss it further.

Daryl

[Dajgoro]

8BIT wrote:

Dajgoro wrote:

As mentioned in another topic, i am thinking about building a video display board with a mcu that would have a framebuffer and colors, but i still need to find a way to make it compact.
A 8051-like mcu would do the trick, since the 8051 has that external ram port, so it can quickly access a big framebuffer.

The Core of my SBC-3 fit on a 2.5"x3.8" PCB and it had a 320x200 color display. It used 8 bits per pixel, which results in 64,000 bytes per frame. It used a 65816, XC95108 CPLD, 32kx8 EEPROM, and 512kx8 SRAM. The CPLD did all of the video timing, with the 8-bit pixel data going to a resistor ladder DAC and then feeding a AD724 to generate the Composite color signal (NTSC or PAL). The AD724 also has an S video output. Since the CPLD used the low PHI2 half cycle, the 65816 ran at full speed. You could program the 65816 to do all of the text generation, along with a full library of graphics routines which your host could call upon. You would have up to 7 frame buffers with the 512k SRAM as well. The animated US flag was done by cycling through the 7 buffers. An interface to the host would come through the CPLD as well. The only downside is the cost. Those parts are kind of expensive.

A photo of the core is at the bottom of this page:
http://sbc.rictor.org/pics3.html

The outline is also present on the main SBC-3 board. Draw a vertical line just left of the 65816 and a horizontal line just under the ground trace below the resistor DAC, and the upper right section is the core.

If this interests you, let me know and we can discuss it further.

Daryl

You forget that the XC95108 is made of Unobtainium, that is why i am looking for a simple and cheap solution. The thing is that i often build all kind of projects, from sbc-s to mcu based stuff, and small alphanumeric lcd-s are just not enough. Also i can't start buying tellys for every project i make, so i really like the idea of a graphic module that can generate composite video, and be connected to a small lcd(hopefully with composite in, but it can be also without).
I thought about building a sbc for this propose, but it gets a bit expensive, and it is an overkill. I think the AT80S51+64k ram might do, but i can't find how many mips does it have.

[8BIT]

No worries. I did a search for that chip but could not find a datasheet from any of my normal sources.

https://sites.google.com/site/retroelec/home

This guy built a color display from an ATMega162 with external RAM. It has several different modes. You may want to look over his design as a possible option.

Daryl

[Dajgoro]

The AtMega162 that is used has the ram interface like the 8051.
I just only have to find out which is faster AT162 or 80S51.
I could map the r/w register interface to the last few bytes of ram, so an external bus can be connected, like a 6502 sbc(for sending commands). The serial input could be used as well.
As for the lcd, a jumper could be added indicating to what should the mcu display the image composite or digital lcd module.

[Dajgoro]

Some ides:
Initial model would have 192x256 6 bit color for tv, or 320x200 for lcd.
External 64k framebuffer.
Host port would be mapped on the external framebuffer ram(probably the last few bytes).
I have lots of pal frequency crystals, so they might be used for precise trimming.

With some software adjustments a 256x341 resolution might be achieved.

Edit: Are there any ic that would act as a bridge for the host interface, something like mini dual port ram? In any case the CY7C130 could be used.

[Dajgoro]

Ill buy the CY7C130 and instructions to the mcu will be inputed in a stack like form through the CY7C130.

[White Flame]

The display from a Nokia 6100 (and other phones) is like this, sending SPI commands to a LCD controller module that independently runs a 128x128 (or 132x132?) display.

You could get some pointers as to which commands you want to support from its docs: https://instruct1.cit.cornell.edu/cours ... torial.pdf

They're as cheap as $15: https://www.sparkfun.com/products/569?, and many people sell such things on eBay, but of course they don't drive composite/VGA/whatever signals for external monitors.