edp.update and epd.partial_update algorithms

mikeheiss commented 9 years ago

When doing an epd.update on the 2.7" display, the full refresh takes over 3 seconds (first showing inverted image, then flashing a number of times). Is there any way to change this algorithm for a faster refresh?

Also, what is the difference in epd.partial_update? (I can't notice any) Say, for example, I only want to refresh the top half of the display - is there any way to do this (while keeping the bottom static/not flashing)?

brodykenrick commented 9 years ago

Partial updates are possible with the chide changes in my fork. You'll need to tweak the code a little but the functionality is there. On 18/12/2014 4:03 PM, "viper4049" notifications@github.com wrote:

When doing an epd.update on the 2.7" display, the full refresh takes over 3 seconds (first showing inverted image, then flashing a number of times). Is there any way to change this algorithm for a faster refresh?

Also, what is the difference in epd.partial_update? (I can't notice any) Say, for example, I only want to refresh the top half of the display - is there any way to do this (while keeping the bottom static/not flashing)?

— Reply to this email directly or view it on GitHub https://github.com/repaper/gratis/issues/19.

CharmingSu commented 9 years ago

If you use V2 (V230+G2, also called Aurora Ma) IC, it's not so suitable to implement partial update due to the block type waveform and slower update than V1 (V110+G1). For how to identify the display type, please visit Pervasive Displays (PDi). PDi will release new EPD in Jan/M-E and on DigiKey which name is V231 (also called Aurora Mb) and embedded G2 IC. The waveform is fully compatible with V110 that we had supported on GitHub. Just some order of scan data and line data need to be adjusted. Keep watching on PDi website!

For partial update, the rules are:

Run the last stage directly without the inverse and blinking stages.
Doesn't need to power off the COG. (of course without power on again)
At the last stage, if the color of previous pixel is the same as the new pixel, you will need to send “Nothing” data byte (01), neither the Black(11) nor White(10) data byte. Otherwise the pixels will be overdriven. It may reduce the lifetime of particles in display and easy to see the ghosting effect.
If the color of previous pixel is different from the new pixels, send the new pixel data.
Keep the same stage time (1.44" and 2" takes 480ms, 2.7" takes 630ms) for better optical performance. If you like to accelerate the update, you are able to reduce the stage time until you can't accept the ghosting effect.
A number of partial patterns or a short while without updates, perform a Global update to remove the ghosting and power off.

By FAE of PDi

CharmingSu commented 9 years ago

New V231 display with G2 driver are available in March 2015 on Digi-Key!

1.44": E1144CS021
1.9" : E1190CS021
2.0" : E1200CS021
2.6" : E1260CS021
2.7" : E1270CS021

The Gratis Github code is upgrading.

For more information of the difference, please visit Pervasive Displays. How to identify your display type, please check the rear label of your display by this link.

By FAE - Charming Su of Pervasive Displays

mikeheiss commented 9 years ago

Will these new displays still work with the SM027 development board?

Please let me know when the Github code is upgraded. Thanks!

CharmingSu commented 9 years ago

Yes. The board(driving circuit) is compatible with all the displays (forward & backward), just the firmware code needs to be revised.

phlips commented 8 years ago

Which files and parts do I have to edit for implementing partial update?

hxw commented 8 years ago

fix has been merged

repaper / gratis

edp.update and epd.partial_update algorithms #19