VGA: Difference between revisions
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The main limit is cost, if the project is close to $25, then I might as well just add a rasPi. I think the best approach is to use SRAM to buffer a bitmap and then sync that up with the monitor. | The main limit is cost, if the project is close to $25, then I might as well just add a rasPi. I think the best approach is to use SRAM to buffer a bitmap and then sync that up with the monitor. | ||
[http://www.digikey.com/product-search/en?mpart=IS61LV5128AL-10TLI&vendor=706 This] sram chip would work. There are some "tsop adapter" relatively cheap. | |||
* http://hackaday.com/2010/11/23/vga-interfacing-avr-microcontrollers/ | * http://hackaday.com/2010/11/23/vga-interfacing-avr-microcontrollers/ | ||
* http:// | * http://www.theresistornetwork.com/2013/03/avr-vga-generation.html | ||
* http://dqydj.net/how-to-produce-640x480-vga-color-video-from-an-arduino/ | |||
* http://www.gammon.com.au/forum/?id=11608 | |||
* http://quinndunki.com/blondihacks/?p=955 | |||
* http://tinyvga.com/avr-sdram-vga | |||
This might work well with double buffering - two ram chips one in read mode, one in write mode and a single bit to switch. | |||
It may also be just fine to accept a certain amount of flicker. Allow the mcu to interrupt the graphics driver. During the interrupt the driver will output black pixels. This allows us to update sections of the image as the mcu needs to. It would be good for displaying mostly static data (text, images) but allows a much higher resolution. | |||
Display sizes in [https://en.wikipedia.org/wiki/Video_Graphics_Array#Standard_graphics_modes standard graphics modes]: | |||
{| class="wikitable" style="text-align: left;" | |||
! width || height || colors || bytes | |||
|- | |||
| 640 | |||
| 480 | |||
| 16 | |||
| 153,600 | |||
|- | |||
| 800 | |||
| 600 | |||
| 16 | |||
| 240000 | |||
|} | |||
I actually think a 256K SPI EEPROM (24LC256) could handle this, if it can output at the necessary speed. That would drop the cost significantly. | |||
[[Category:Electronics]] | [[Category:Electronics]] | ||
[[Category:Notes]] | [[Category:Notes]] | ||
Latest revision as of 22:37, 11 February 2017
I would like to be able to output VGA from AVR projects. VGA LCDs (used) are incredibly cheap. I don't need incredibly high resolution.
The main limit is cost, if the project is close to $25, then I might as well just add a rasPi. I think the best approach is to use SRAM to buffer a bitmap and then sync that up with the monitor.
This sram chip would work. There are some "tsop adapter" relatively cheap.
- http://hackaday.com/2010/11/23/vga-interfacing-avr-microcontrollers/
- http://www.theresistornetwork.com/2013/03/avr-vga-generation.html
- http://dqydj.net/how-to-produce-640x480-vga-color-video-from-an-arduino/
- http://www.gammon.com.au/forum/?id=11608
- http://quinndunki.com/blondihacks/?p=955
- http://tinyvga.com/avr-sdram-vga
This might work well with double buffering - two ram chips one in read mode, one in write mode and a single bit to switch.
It may also be just fine to accept a certain amount of flicker. Allow the mcu to interrupt the graphics driver. During the interrupt the driver will output black pixels. This allows us to update sections of the image as the mcu needs to. It would be good for displaying mostly static data (text, images) but allows a much higher resolution.
Display sizes in standard graphics modes:
| width | height | colors | bytes |
|---|---|---|---|
| 640 | 480 | 16 | 153,600 |
| 800 | 600 | 16 | 240000 |
I actually think a 256K SPI EEPROM (24LC256) could handle this, if it can output at the necessary speed. That would drop the cost significantly.