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Re: EXCELGRAPH - ISA Video Display Controller

Posted on 2021-04-15, 09:35

Yes, CH9294E variant is required in PDIP-20 package. To my knowledge, the G version is mostly in SMD package. And it is not compatible with this design. I think in my case, Windows 98 detected the card as plain VGA as well. I forced the drivers to ET4000/W32i later on.

Re: EXCELGRAPH - ISA Video Display Controller

Posted on 2021-04-15, 08:09

Hi root42, I checked the datasheet of the ICS2494 IC. It seems to be compatible with the dual PLL frequency synthesizer made by Chrontel CH9294. I have the datasheet for the Chrontel CH9294 IC, if it is of any help. PS: I have just seen that I made a labelling error in my schematic. I listed the …

Re: EXCELGRAPH - ISA Video Display Controller

Posted on 2021-04-14, 20:33

Thank you for the Keystone bracket hint. I will look into the Keystone drawings and check the measurements first. If it fits I will take a couple of them. Regarding the DRAM, the ones I used are a newer than what would've been normally used in the early '90s. But they are still obsolete parts. The …

Re: EXCELGRAPH - ISA Video Display Controller

Posted on 2021-04-14, 18:15

I know that eBay prices are particularly high for ET4000/W32i cards. I don't think there were that many made (at least not like Trident cards) and they offer great ISA performance. I think only one other card based on a variant of Cirrus Logic GD series chip is on par with the Tseng models. However …

Re: EXCELGRAPH - ISA Video Display Controller

Posted on 2021-04-14, 16:46

I never thought about 8-bit card mode thus I decided to use the 16-bit extended signals for addressing. In addition, my 80386DX project PCB has the LA17-LA19 (16-bit) signals hardwired to the SA17-SA19 (8-bit) signals. But the video card works OK with other PCs, up to Pentium 233 MHz (that's the …

Re: EXCELGRAPH - ISA Video Display Controller

Posted on 2021-04-14, 10:25

SEGE is a multi-purpose pin. The most interesting is that for 16-bit ISA operation (linear design), it is tied to system ISA bus A23 signal. In other system designs it is connected differently. However I was not interested in anything other than ISA thus I don't know the other functions. Later edit: …

Re: EXCELGRAPH - ISA Video Display Controller

Posted on 2021-04-13, 13:04

Can you check with Windows 98 instead? When I installed Windows 98 I tried different drivers and only some worked. In the end I think I used the ones provided by Microsoft. I can check later on today when I'll have time. I remember that some drivers would not enable the accelerator and would default …

Re: EXCELGRAPH - ISA Video Display Controller

Posted on 2021-04-13, 06:01

I wouldn't think the CPU doesn't have enough power to generate data for an ISA-class card. Even an accelerated one. But then again, in a simulation, everything might be possible. The project went live on my site. I also injected my own ASM routine in the VIDEO ROM BIOS binary image and then burned …

Re: EXCELGRAPH - ISA Video Display Controller

Posted on 2021-04-12, 09:20

I would deffinetely go with IDA. Or if you'd like to dig deeper then give SoftICE a try. That would bring back interesting memories of the old times. You can step into each asm routine in real-time. But, as you might've guessed already, it takes a lot of time. And reversing a poorly written …

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