PowerBook 145B LCD video output format?

[PotatoFi]

I'm investigating alternative uses for the PowerBook 145. It's well-documented that these don't have their own way to output video, but I got to thinking about pulling video from the LCD output. Do we know anything about the video format or protocol that the 140/145/145B uses to talk to the Sharp LCD over the flex cable?

 

[This Does Not Compute]

I know LVDS was a common protocol for laptop displays before DisplayPort took over, but can't remember if it's old enough for the early PowerBooks to have used.

 

[Kai Robinson]

It's a straight up parallel interface, either 6 or 8 bit depending on the colour depth and if it's active or passive matrix. @3lectr1c may be the person for this though.

 

[PotatoFi]

Thanks @Kai Robinson, that's a good lead. Do you know of any devices that are meant to work with a parallel video interface like that, or any specs I can look at? I'm not turning up very much when I Google this stuff.

Related, I found a schematic for the PowerBook 140, which might be helpful.

 

[3lectr1c]

It's a straight up parallel interface, either 6 or 8 bit depending on the colour depth and if it's active or passive matrix. @3lectr1c may be the person for this though.

I don't know for sure here unfortunately, but I do know that parallel was the standard around this time. LVDS didn't come around till....late 90s?

 

[arroz]

Hi,

I'm sort of thinking about looking into doing something similar if I can't find a replacement panel for my 145. Having a controller like an RPI or a Pico controlling a more modern LCD grabbing the frame buffer from the parallel data, stuffed inside the display case (which is huge for current electronics these days). Did you find any useful info regarding the exact protocol these things use?

Thanks,

Miguel Arroz

 

[AvadonDragon]

I was looking into this a while ago but didn't make it very far due to lack of information availability. Right before I gave up though I got a tip that it MIGHT be in the Macintosh Portable developer notes which I never looked into.

 

[PotatoFi]

I don't remember exactly what I was up to, but I have a bunch of bookmarks for various ICs that I thought were related, looking to find out how the protocol worked:

• LM64P12 Datasheet
• LM64K112 Datasheet
• Datasheets starting with LM64P
• LM64P832 Datasheet
• LM64P83 Datasheet

The Macintosh Portable developer notes sound like the next place we should look.