Denial

The PRG is extremely vague in that regard. You'd better take a sharp look into the datasheet of the 6522 for this. Thanks Mike. I did have a look through the 6522 datasheet a couple of weeks ago, and it went over my head. Now that I've done a bit more reading it might make more sense. The Interrupt...

It never ceases to amaze me just how much is going on with such a 'simple computer'. I can see how IGONE and the other vectors nearby would come in handy for creating wAx. I'm right now reading the PRG chapter on VIA chips, but can't find anything about how to access them, or how they signal an inte...

Hello. I've been having a mess with interrupts, and have managed to wedge my code in by 'poking' to address $0314-5. This is letting me create at least some semblance of 'multi-tasking'. Please can someone tell me if there any other methods of handling interrupts / event-driven stuff, or is that our...

From screenvalue to PETSCII input in X Y = X AND 63 IF (X AND 32) = 0 THEN Y = Y OR 64 IF (X AND 64) THEN Y = Y OR 128 result in Y (if X>127 then char is reverse) From PETSCII to screenvalue input in X IF (X AND 96) = 0 THEN REM it is a control code X = X AND 191 IF X > 127 THEN X = X AND 127 : X =...

srowe wrote: ↑Thu Dec 17, 2020 10:16 am
Yes, screen codes are a (scaled) index into the character generator, by default the ROM at $8000.

PETSCII is mapped to these coded by the KERNAL print routines.

Thanks srowe. I might have a prod around at $8000.

Ah... In reading the thread about memory location 36869 below, I decided to check out the reference to Compute's Programming the Vic... https://commodore.bombjack.org/vic-20/books-vic.htm pp585 in Appendix J lists 'screen codes', which is exactly what I was after. I can't believe I answered my own q...

Hello folks. POKE 4096,1 (expanded VIC20) puts the character 'a' in the top left corner. POKE 4096,2 displays a b, and so on I was expecting PETSCII codes ( a= $41, b= $42 etc), but nope! Are the numbers a reference to the character 'map' in character ROM perhaps? What I found, with chars unshifted:...

Sorry to resurrect this thread, but I've only just discovered it and wanted to congratulate all involved. It reminds me of a conversation I once overhead about the Duckworth-Lewis Method for determining who wins the cricket when it starts raining: ( https://en.wikipedia.org/wiki/Duckworth%E2%80%93Le...

Wow! We all thought that Clive Sinclair was insane, but he got it right... just 40 years too soon... It's fascinating that computer designers and manufacturers have gone pretty much full circle to end up at the place that we never left! IMG_20201106_173059939.jpg https://www.raspberrypi.org/products...

I'd presume quite a lot of fellow coders try to optimize their code for size or speed ... and never finish it. I think that, for me at least, this is as more about learning, about process and about engineering and optimizing code to the nth degree. I've got a big ol CRT monitor, real 1541, crappy o...

Done, thanks.

SkydivinGirl wrote: ↑Fri Oct 23, 2020 8:25 am I only have six units left.

Hello Heather.

Please can I get a kit and case.

I'm happy soldering, but my sausage-fingers are no good at surface mount, so would appreciate you doing those bits for me.

mingle wrote: ↑Sat Oct 24, 2020 9:05 pm Anyone in the UK willing to buy one for me and post it on to me in Australia?

I'll cover all costs...

Cheers,

Mike.

I'm happy to do this for you Mike. Drop me a PM.

Kweepa wrote: ↑Mon Oct 19, 2020 8:19 am I tend to just dive in and start writing the bits that interest me, and then sort it out later.
That could be why I have a drive full of unfinished projects though.

Yeah, I tried that.
Probably explains all these grey hairs!

Time to get out the notebook and pen.

Write your own chrout replacement from scratch with only the features you really need. You know what you want to achieve, the code has to simple reflect that. I've had a good poke around the internal organs of CHROUT and concluded exactly what you said: better just to write my own from scratch. I'v...