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...

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 ....

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

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...

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...

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 ...

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...

Although it is not a VTech system, yesterday a new, very nice mega demo was released for the expanded TI-99/4A: https://www.youtube.com/watch?v=ZhSUhE03XFw http://www.pouet.net/prod.php?which=68783 As you know, it has the same VDP and PSG as the Creativision, but instead of a 2 MHz 6502 or 3.5 MHz Z...

By the way, the reference in January 1984 to the mid-range Laser 2001 which is able to run ColecoVision software (sic!) is present here. No picture of that computer though, but a picture of the Laser 3000 on the previous page. While I'm willing to accept that neither the CreatiVision nor the 2001 we...

See also the back side of the Laser 2001 box. :) Of course VTech may have manufactured several different plotters with the same look, if those connect directly to the expansion bus. I never quite figured out if the 200/300, 350/500/700 and the 2001 have different kind of expansion buses and pinouts....