Search found 4 matches

by ThomHa
Mon Mar 26, 2018 2:03 pm
Forum: Other VTech systems
Topic: Great TMS Video Chip Demo
Replies: 12
Views: 3756

Re: Great TMS Video Chip Demo

Just on the three threads I feel even slightly qualified to pick up: 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? I think so, because he has also written that work on the original started in 1977 and w...
by ThomHa
Thu Mar 22, 2018 6:18 pm
Forum: Other VTech systems
Topic: Great TMS Video Chip Demo
Replies: 12
Views: 3756

Re: Great TMS Video Chip Demo

Picking up some loose threads, far too late... There's a cache of TMS development memos that strongly implies the chip was offered to third parties from day one, but TI took a long time to find any buyers and get production working properly. See e.g. The Video Display Processor Debacle from 1981. Th...
by ThomHa
Fri Mar 16, 2018 12:20 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?

If you add 0x80 then you'll write to a register instead of to VRAM. Logic is: To write to a register, write the value you want to set, then write (the register address) + 0x80. To write to VRAM, write the low byte of the address, then write the high byte + 0x40, then write the value to write to the ...
by ThomHa
Tue Mar 13, 2018 3:11 am
Forum: Introduce yourself!
Topic: Hello from New York City
Replies: 1
Views: 638

Hello from New York City

I'm a British ex-pat with a penchant for the semi-obscure; I have not acquired any real hardware because, well, my accommodations are the size that they tend to be in New York City, but I'll just be honest: the split keyboard, even if it is a membrane, is cool. I'll probably try to write some sort o...