Search found 453 matches

by carlsson
Wed Nov 21, 2018 11:01 am
Forum: Other VTech systems
Topic: Colecovision Module
Replies: 4
Views: 90

Re: Colecovision Module

Great write-up! I'm forgetting, do the Salora branded game cartridges say Manager somewhere on the screen instead of Laser 2001 or CreatiVision? From what I understand, quite a bit of the interior electronics in Salora products were manufactured elsewhere (e.g. Siemens, Luxor) and possibly just asse...
by carlsson
Tue Mar 27, 2018 10:45 am
Forum: Other VTech systems
Topic: Great TMS Video Chip Demo
Replies: 12
Views: 3756

Re: Great TMS Video Chip Demo

That the TI VDP was worked on in 1977-78 is interesting as the GI STIC is of similar lineage and it sometimes is claimed one was inspired by the other. Of course we also have Atari, to a lesser extent Commodore and a bunch more hardware developers around the same time. In reality all of them probabl...
by carlsson
Fri Mar 23, 2018 2:36 pm
Forum: Other VTech systems
Topic: Great TMS Video Chip Demo
Replies: 12
Views: 3756

Re: Great TMS Video Chip Demo

Nice documents, and cool game. When Karl Guttag writes they've had fully functional VDP's for 2.5 years by April 1981, does he mean the original 9918 without bitmap mode etc? As for the picture quality, would that be due to what happens once you feed its signals to a RF modulator, something TI avoid...
by carlsson
Wed Mar 14, 2018 2:24 pm
Forum: Games programming
Topic: [cc65]How can I redefine characters and use colors?
Replies: 6
Views: 1538

Re: [cc65]How can I redefine characters and use colors?

Very good questions! Actually I copied that bit of code from Kurt's Titanic demo. In his comments he mentions the BIOS routine VDP_Regwrite at $FE1F: BIOS_VDP_Regwrite = $FE1F ; this is a short subroutine which writes the contents of a into VDP register x. It can also be used for initializing the re...
by carlsson
Tue Feb 27, 2018 11:03 am
Forum: Games programming
Topic: [cc65]How can I redefine characters and use colors?
Replies: 6
Views: 1538

Re: [cc65]How can I redefine characters and use colors?

I believe you need to set up the VDP vectors at $BFF0. I used these values previously: .byte $00 ; VDP 0: External video off, M2=0 .byte $A2 ; VDP 1: 16K mode, Screen not active, Generate interrupts ; M1=0, M3=0, Sprites = 16x16 unmagnified .byte $04 ; VDP 2: Pattern Name Table = 04 * $400 = $1000 ....
by carlsson
Tue Feb 27, 2018 10:52 am
Forum: Homebrew software and hardware (excluding games)
Topic: [VDP] What are the two bytes that have to be written into the VDP status address?
Replies: 3
Views: 1050

Re: [VDP] What are the two bytes that have to be written into the VDP status address?

You add $40 to indicate the address is set up for writing, or $00 to indicate it is set up for reading.

This doc is for the Spectravideo but is has the same type of VDP, see Address Register: http://samdal.com/svvideo.htm
by carlsson
Tue Jun 27, 2017 9:57 am
Forum: Other VTech systems
Topic: Great TMS Video Chip Demo
Replies: 12
Views: 3756

Re: Great TMS Video Chip Demo

True, we have discussed that before and the likelyhood that one and the same manufacturer - whoever it was - had several reference designs based on the TI custom chipset but with different CPUs attached to it, of which Coleco went with the Z80 design and the 6502 design was left for VTech to acquire...
by carlsson
Mon Jun 26, 2017 10:34 pm
Forum: Other VTech systems
Topic: Great TMS Video Chip Demo
Replies: 12
Views: 3756

Re: Great TMS Video Chip Demo

Regarding the VDP, I read the other day that supposedly it was designed by Milton Bradley (the toy/game company) to be used in a 16-bit video game manufactured by Texas Instruments. It is not clear what is fact and what is fiction, but the gospel is that TI said "fool you!" to MB, grabbed the design...
by carlsson
Wed Apr 05, 2017 8:54 am
Forum: Hardware
Topic: How to build a creatiVision power supply
Replies: 41
Views: 22467

Re: How to build a creatiVision power supply

Sad to say, that spare 1541 floppy drive has been resting in its plastic bag for over 1.5 years. In theory I think it will work to reuse the transformer part of its power supply, as it should both have the windings at the right voltages, and designed to handle the required loads of current. Someone ...
by carlsson
Tue Feb 14, 2017 1:16 pm
Forum: General CreatiVision forum
Topic: Creative Computing on CreatiVision
Replies: 13
Views: 8630

Re: Creative Computing on CreatiVision

Great news! In case I come across more references, I'll post them here. Last year I went through a number of Japanese computer magazines I/O which also had a gaming oriented publication, but so far I can't recall seeing anything about the Cheryco release. It also makes me wonder if Sanyo Video in Ge...