Re: All the exact differences in programming interface for EGA vs VGA?

Posted on 2021-06-27, 22:46

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by mkarcher

in PC Emulation

in PC Emulation

superfury wrote on 2021-06-27, 22:42: It's still setting up the Misc Output Register incorrectly, though? It's pretty much set to 00h all the time, Can you post a link to the BIOS that exhibits this behaviour?

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Re: All the exact differences in programming interface for EGA vs VGA?

Posted on 2021-06-27, 22:34

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by mkarcher

in PC Emulation

in PC Emulation

I assume (but don't know) that you can read from planes two or three if you set the read map select register to two or three. I tested the behaviour in text mode (which uses odd/even) on a Trident TVGA8900, an ET4000AX and a GeForce 4 MX 420. On all three of these cards, I can read the font from …

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Re: All the exact differences in programming interface for EGA vs VGA?

Posted on 2021-06-27, 22:01

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by mkarcher

in PC Emulation

in PC Emulation

This looks about the way I expect it to be handled in real hardware. I'm unsure about read map selection, though. You seem to always read from the first bit set in *planes, so after OddEven_decode, you will always read from plane 0 or 1. This might be correct, but my guess is (I need to test that …

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Re: What is Controller-Number 6 in a Control-Change message?

Posted on 2021-06-27, 21:52

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by mkarcher

in MT-32 Development

in MT-32 Development

ok before are two msg in this order B0 65 0 B0 64 0 B0 6 and changing 3rd byte OK, so previous two messages select the "pitch bend range" registered parameter by its "registered parameter number" 0. If that parameter is selected, the third byte of B0 06 xx specifies how many semitones you can bend …

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Re: Sound Blaster 16 ct2230 works only for a few minutes

Posted on 2021-06-27, 21:27

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by mkarcher

in Marvin \ Sound

in Marvin \ Sound

Also, I have read that if I can't find caps with the same exact specs, it's preferable to go for higher capacitance than lower; is this a good rule of thumb, or are there other considerations to make there? Both the capacity and the ESR of caps used inside the audio path have an effect on the …

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Re: All the exact differences in programming interface for EGA vs VGA?

Posted on 2021-06-27, 21:19

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by mkarcher

in PC Emulation

in PC Emulation

This is what I've gotten with this combined for Odd/Even mode: (code snipped) This looks about the way I expect it to be handled in real hardware. I'm unsure about read map selection, though. You seem to always read from the first bit set in *planes, so after OddEven_decode, you will always read …

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Re: What is Controller-Number 6 in a Control-Change message?

Posted on 2021-06-27, 21:02

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by mkarcher

in MT-32 Development

in MT-32 Development

A "data entry" control change message shouldn't come on its own. It's part of the RPN/NRPN system. You first have to select a parameter number by writing an officially assigned 14-bit parameter number into controls 100 and 101 (B0 64 01 / B0 65 00) for parameter number 1 which is "master fine tuning …

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Re: All the exact differences in programming interface for EGA vs VGA?

Posted on 2021-06-27, 20:47

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by mkarcher

in PC Emulation

in PC Emulation

So: - If Sequencer Memory Mode bit 2 isn't in Odd/Even mode, use planar mode addressing for writes. The other mentioned bits aren't used for that. - If Graphics Mode bit 4 isn't in Odd/Even mode, the same applies as mentioned abover for Sequencer Memory Mode bit 2. - If the read/write is in odd/ …

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Re: Sound Blaster 16 ct2230 works only for a few minutes

Posted on 2021-06-27, 20:38

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by mkarcher

in Marvin \ Sound

in Marvin \ Sound

That said, I have done some more research and I seem to understand that I want to go with Japanese brands for the most part (Rubycon, Panasonic, Sanyo and the like), but I still don't know much about which specific ones to get (at equal rating, that is). I am imagining that I need to stick with …

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Re: All the exact differences in programming interface for EGA vs VGA?

Posted on 2021-06-27, 20:29

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by mkarcher

in PC Emulation

in PC Emulation

But isn't Odd/Even mode enabled by those other two registers (Sequencer Memory Mode bit 2 cleared for CPU writes and graphics mode register bit 4 set for CPU reads. Otherwise, it's in planar mode instead of odd/even mode and the known and documented planar mechanics apply? (Although Chain 4 …

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Re: All the exact differences in programming interface for EGA vs VGA?

Posted on 2021-06-27, 20:16

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by mkarcher

in PC Emulation

in PC Emulation

Isn't bit 0 for the VRAM gotten from CPU address bit 16 when the miscellaneous graphics register bit 1 is set? So does that bit in the register override the bit 5 of the misc output register? As I understand it, in odd/even mode (enabled by misc graphics bit 1, A0 is taken from misc output bit 5 …

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Re: All the exact differences in programming interface for EGA vs VGA?

Posted on 2021-06-27, 17:29

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by mkarcher

in PC Emulation

in PC Emulation

You are talking about odd/even mode, where A0 from the CPU selects either planes 0&2 or 1&3. Which plane(s) actually get written to is selected by the map mask register, which typically is 03h in odd/even modes, so planes 2 and 3 are out of reach. As A0 is used to select the planes, there is no A0 …

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Re: I cannot figure out what SoundBlaster is this?

Posted on 2021-06-27, 11:31

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by mkarcher

in Marvin \ Sound

in Marvin \ Sound

dank0 wrote on 2021-06-27, 07:38: When i set blaster in DOS to A200 I5 D1 T4 it plays only music in doom, not any effects. A200 is wrong. The card is jumpered to its default setting A220.

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Re: Help with P55T2P4 interface headers cluster

Posted on 2021-06-26, 22:13

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Don't worry. Everything is easier than you expect. For fans, the traditional coloring is GND=black, POWER=red. As most fans are 12V fans, the red wire on PC fans is supposed to be connected to +12V. ATX added a speed sensor output to fans, which often is yellow. The speed sensor output is designed …

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Re: Sound Blaster 16 ct2230 works only for a few minutes

Posted on 2021-06-26, 18:15

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by mkarcher

in Marvin \ Sound

in Marvin \ Sound

While attempting a fix, however, I still plan on doing some diagnosis first, in order to at least get better acquainted with the skills of the trade and transferring them to similar odd jobs on my appliances. I have read about using an ESR meter in order to determine if a cap is still good or not …

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Re: TVM MD-3N - EGA or CGA Monitor?

Posted on 2021-06-26, 14:24

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by mkarcher

in Marvin \ Video

in Marvin \ Video

However, that doesn't mean that should the monitor have all the pins (including pin 7), that it is an "enhanced" EGA monitor. The best way to confirm is to check for continuity between pins 1 & 2 (i.e., if both pins are connected to ground). If there is continuity, then (as mentioned previously), …

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Re: EXCELGRAPH - ISA Video Display Controller (ET4000/W32i)

Posted on 2021-06-26, 14:03

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by mkarcher

in Marvin \ Video

in Marvin \ Video

Series termination usually does not require 300 Ohm resistors. As ALEKS tried at first, 10 Ohm to 33 Ohm are typical values for series termination. Of course, I do believe you that increasing the resistance helps fixing the problems with your board, but if you need that high, the primary purpose of …

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Re: The TANDY DAC, how its implented ?

Posted on 2021-06-26, 13:23

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

FreddyV wrote on 2020-10-05, 08:24: Unfortunately, it use a DMA controller PIN that is not on the ISA Bus. (TC) It is on the ISA bus, although some sources may call it differently. TC ("terminal count") aka EOP ("end of process") is on ISA pin B27.

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Fixing an Acer FX-3D/Pro Radio: AD1816 + integrated radio

Posted on 2021-06-26, 13:17

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by mkarcher

in Marvin \ Sound

in Marvin \ Sound

I recently picked a Acer FX-3D sound card with integrated radio from my box of old ISA cards. It's a typical late ISA age sound card featuring the AD1816 sound chip. This card is special in that it also contains an FM radio receiver in the shielded box. SG1L9316.JPG A typical AD1816 sound card …

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Re: EXCELGRAPH - ISA Video Display Controller (ET4000/W32i)

Posted on 2021-06-25, 20:10

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by mkarcher

in Marvin \ Video

in Marvin \ Video

Below 1MB it seems simple(upper pins are cleared), but when addressing past 1MB, 8-bit cards would read an address below 1MB instead? Thus incorrectly decoding addresses(e.g. 1A0000 would map to VRAM?)? Anyone knows what happens on the ISA slot in this case? This one is quite simple to answer: …

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