Re: Tandy 2500 XL "C0 to 1E0" patching

Posted on 2022-05-20, 14:20

by

by bakemono

in Marvin \ Sound

in Marvin \ Sound

I have a tandy third-party soundcard that I've installed on my Sensation 2 at the default port (C0h) and it doesn't actually interfere with anything (SO FAR), despite that being the supposed second DMA controller port. Port C0 is the address register for DMA channel 4, which I don't think is …

---

Re: Tandy 2500 XL "C0 to 1E0" patching

Posted on 2022-05-20, 14:04

by

by bakemono

in Marvin \ Sound

in Marvin \ Sound

I can't recall exactly from memory, but most of the mentioned games in the OP are out c0h, al which is basically a 2 byte instruction. Patching to 1E0h is more involved: mov dx, 1e0h out dx, al 4 bytes right there. Unless there's a couple of NOP's in the sound subroutine it will be a gargantuous or …

---

Re: The most powerful Windows 2000 GPU?

Posted on 2022-05-18, 14:00

by

by bakemono

in Marvin \ Video

in Marvin \ Video

Somebody reported running a GTX285 on stock Win2k. GTX 480 or the like might be possible also, as these are supported cards under the 258.xx drivers. With extended kernel I use a GTX 660 on the 310.70 driver. Other driver versions seem to always BSOD. For issues with BWC kernel you should reach out …

---

Re: What retro activity did you get up to today?

Posted on 2022-05-16, 12:37

by

by bakemono

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Powered on my dot matrix printer (Panasonic KX-P 1180) to print some adhesive labels on tractor-feed paper. Also... I've been noticing that there are more than a few hobbiest ISA card designs around, but no PCI cards? It seems that the official PCI spec is not freely available but I found something …

---

Re: I miss the 70’s, 80’s, and 90’s

Posted on 2022-05-16, 12:23

by

by bakemono

in Milliways

in Milliways

Real answer: socketable and 5V tolerant programmable logic! Many product lines from the '90s are long since dead and gone: FLASHlogic, FLEX, AMD MACH, Cypress 37000, etc.

---

Re: General ISA Bus Mastering musings/questions.

Posted on 2022-05-16, 00:02

by

by bakemono

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The 8514/A (mind the "/A", the IBM 8514 is a monitor , the IBM 8514/A is a video card ) doesn't do bus mastering. Oh? Must have been the XGA and not 8514/A http://bitsavers.trailing-edge.com/pdf/ibm/pc/cards/IBM_VGA_XGA_Technical_Reference_Manual_May92.pdf and ISA version of XGA? https://www. …

---

Re: Ati Rage Mobility M1 Laptop find and story, help with games

Posted on 2022-05-15, 23:39

by

by bakemono

in Marvin \ Video

in Marvin \ Video

I had a Dell Latitude L400 with Rage Mobility M. Great laptop but not much for games. It could run Warcraft III at 640x480 but it was a bit choppy.

---

Re: 3DMark99 gives nearly same results 640x480 as it does 1024x768. CPU limited?

Posted on 2022-05-15, 16:18

by

by bakemono

in Marvin \ Video

in Marvin \ Video

Vsync getting stuck on and limiting the score to 5~6000 also seems to be a common problem with 3Dmark99

---

Re: General ISA Bus Mastering musings/questions.

Posted on 2022-05-15, 16:04

by

by bakemono

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Whole reason for this topic is my curiosity if it was at all possible to release a 2D sprite accelerator in late 80 286 to very early 90 slow 386 era, a PowerVR PCX1/2 of its time :). One alternate history timeline could see Atari introducing Lynx Suzy blitter (1989) on an ISA card. Another option …

---

Re: I miss the 70’s, 80’s, and 90’s

Posted on 2022-05-14, 16:36

by

by bakemono

in Milliways

in Milliways

I'm gonna say that back in the '70s, there weren't as many people who would incorrectly use an apostrophe in a plural. I miss that.

---

Re: How does data get stored in 16-bit addresses using 8-bit address RAM chips?

Posted on 2022-05-09, 10:25

by

by bakemono

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

(For values above 256K the next bit would go to 1, and that bit would tell it to store in the second column of chips, and so on. No, it's the lowest bit that tells which byte it is. With a 16-bit bus you have the ability to access 16 (18) chips at the same time to read/write two consecutive bytes. …

---

Re: How does data get stored in 16-bit addresses using 8-bit address RAM chips?

Posted on 2022-05-08, 09:38

by

by bakemono

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Didn't check the pic (JS required) but I guess you have 72 chips all together? That's most likely going to be 4x banks of 512KB, where each bank has 16 chips corresponding to data bits on the 16-bit data bus, and 2 additional chips for parity. The address of the memory error will tell you which …

---

Re: Cant get Win 32s or video for windows working on win 3.11

Posted on 2022-05-07, 08:34

by

by bakemono

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Did you try installing in a different order? One piece of software could be installing an updated file that gets reverted to an older version by VFW / Win32s. The best thing to do would be make a copy of your WINDOWS directory, especially SYSTEM.INI, and maybe CONFIG.SYS / AUTOEXEC.BAT in case there …

---

Re: Clock doubling circuit for Turbo XT's!

Posted on 2022-05-07, 08:28

by

by bakemono

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Maybe someone else can confirm but IIRC the NEC V20/V30 manual called for a clock with 50% duty cycle, while 8088/8086 use 66% duty cycle. It stands to reason that the V20/V30 may not reach their rated speed on boards designed around the Intel-style clock. You'd be at 8.3MHz on a "10MHz" chip but …

---

Re: Null Bridgeboard Project?

Posted on 2022-05-04, 10:05

by

by bakemono

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Full length Amiga cards are huuuuuuge. I wonder how much it would cost to get those made. Are there any drivers to use ISA cards on the Amiga? I remember hearing that you could use a network card through the bridge board but I don't know if the Amiga accesses it directly or if it requires software …

---

Re: Modify system palette in Windows 3.1 (VGA)

Posted on 2022-05-04, 09:40

by

by bakemono

in Milliways

in Milliways

If Win 3.1 indeed uses the default palette set by the BIOS, then how about patching the int 0x10 handler?

---

Re: What retro activity did you get up to today?

Posted on 2022-05-03, 02:31

by

by bakemono

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Look at this real interesting hole though, the eZ80! lol eZ80 is kind of the opposite of the Z280. They did a great job of extending the address space this time but didn't bother trying to extend the instruction set in other ways. Too bad there is no PLCC or DIP version. Anyway I just had a …

---

Re: OPNA (YM2608) based soundcard for IBM PCs and compatibles possible?

Posted on 2022-05-02, 01:29

by

by bakemono

in Marvin \ Sound

in Marvin \ Sound

Schematic and PLD code for my YM2203 card are on my site (march 16) . YM2608 has the same audio output and bus interface (except it can take a higher clock frequency, so 14MHz divided by two could be used instead of dividing by four, 22V10 could probably replace the ATF750). The big differences are …

---

Re: What retro activity did you get up to today?

Posted on 2022-04-29, 03:07

by

by bakemono

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I saw Zilog Z280 CPUs in PLCC-68 for sale on auction site, and then found a blog post about people using them for small homebrew boards. I was starting to feel the urge to design my own board. Then I looked through the Z280 manual and changed my mind... The banking/paging scheme they used to extend …

---

Re: Nec PC-9821 support and compatibility

Posted on 2022-04-27, 20:51

by

by bakemono

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yeah, PC-98 use x86 CPUs like others, but the system architecture is very different that you can't just run I386 software as-is, and NEC98 software won't run as-is on standard I386 PCs, either. Windows has a hardware abstraction layer. Hence there is an enormous category of software for which the …

---