Instruction timings, with a view to video generation

[Iain_C]

Hi all,

I'm a new PICAXE user but familiar with uCs in general.

I'm trying to do PAL composite video signal generation in software on an 18X. I think it should be doable even at 4Mhz, albeit with low horizontal resolution.

But to get it working I'm going to need per-cycle accuracy. Is there a PDF of instruction timings for interpreted PICAXE basic? I can't seem to find anything on this..

See eg http://www.brouhaha.com/~eric/pic/pictock.html or http://www.rickard.gunee.com/projects/ for some background on this topic if you're interested.

Many thanks for any help anyone can offer

Best,
Iain
www.coldcity.com

 

[Iain_C]

Aha, just found some relevant threads - dont worry too much about this. Looks like it might not be doable; ref http://www.rev-ed.co.uk/picaxe/forum/topic.asp?topic_id=5013&forum_id=27&Topic_Title=Command+Execution+Time&forum_title=PICAXE+Forum&M=True&S=True.

Although I'd love to hear how Wilf would tackle a video output stage for a PICAXE project, given the ZX97

(Wilf, you don't know me, but your work seems to crop up everywhere - I have used and love your reversing H-bridge design)

 

[wilf_nv]

Hello Iain,

Thanks for the kudos. I'm still actively involved designing for Sinclair and Beam aplications and from time to time some ideas from those worlds spill over into this forum.

It may be possible to combine a PICAXE with a video PIC or a dedicated video subsystem but it is not cost effective and would consume more power than for example using a graphics LCD.