13 replies to this topic

[Kr0tki]

Hello,

I've got a few questions about the XEP80 interface. The data on the Net is somewhat confusing, maybe some could help me fill the blanks.

1. Are there two different versions of the XEP80, one for 50Hz displays and one for 60Hz displays? Or is there only one version that can be switched to either ow the two by software?
2. What is the character cell size in the text mode? There are conflicting reports - one says that the size is 7x10; another claims that the height is 11 pixels. 11 pixels would give 275 scanlines, which is too much for the NTSC standard. So I'm suspecting that the character cell size is different for 50 and 60Hz modes. Is it true?
3. Anyone knows what is the frequency of the XEP80's pixel clock? I need this to accurately compute the XEP80's pixel aspect ratio.

[Stephen]

To the best of my knowledge, there is only one version. The SDX driver can make the XEP80 switch between PAL and NTSC modes via command line switch.

I cannot answer your other two questions, but I will say this. I have never found a display device that didn't completely "chop off" the 25th line of text. My 1084S does (and no amount of adjusting the size controls on the back will fix it), every CRT and LCD screen I have tried cuts it off, and two different models of VGA scan doublers cut it off. It wouldn't surprise me if it is outputting too many lines.

[IndusGT]

Sorry if this has been covered before, I've looked in the thread as well as Flashjazzcat's site. Does the LAST WORD work with the Xep 80?

Thanks

Edited by IndusGT, Mon Apr 4, 2011 7:02 AM.

[flashjazzcat]

IndusGT, on Mon Apr 4, 2011 7:02 AM, said:

Sorry if this has been covered before, I've looked in the thread as well as Flashjazzcat's site. Does the LAST WORD work with the Xep 80?

Nope, sorry. The version equipped with display drivers for VBXE and XEP80 isn't finished yet.

[IndusGT]

flashjazzcat, on Mon Apr 4, 2011 7:08 AM, said:

IndusGT, on Mon Apr 4, 2011 7:02 AM, said:

Sorry if this has been covered before, I've looked in the thread as well as Flashjazzcat's site. Does the LAST WORD work with the Xep 80?

Nope, sorry. The version equipped with display drivers for VBXE and XEP80 isn't finished yet.

Ok, that's good, I did not know that development was ongoing still with The last word. I bet it will look great with the VBXE

[Kr0tki]

Stephen, on Mon Apr 4, 2011 5:52 AM, said:

To the best of my knowledge, there is only one version. The SDX driver can make the XEP80 switch between PAL and NTSC modes via command line switch.

Thanks. Do you know where I can obtain the SDX driver (and possibly some instructions)?

Stephen, on Mon Apr 4, 2011 5:52 AM, said:

I cannot answer your other two questions,

Yes you can Computing the character cell height is a matter of displaying a inverse-video character and counting number of scanlines it takes. Could you check it out in your free time?

Stephen, on Mon Apr 4, 2011 5:52 AM, said:

but I will say this. I have never found a display device that didn't completely "chop off" the 25th line of text.

Yup, I'm aware of that. 275 lines is more than a typical PAL TV displays ,which is about 260 lines.

[flashjazzcat]

IndusGT, on Mon Apr 4, 2011 7:28 AM, said:

I did not know that development was ongoing still with The last word.

As much as is possible with a single brain and one pair of hands.

Quote

I bet it will look great with the VBXE.

It does. You can download the VBXE beta from my website. It's far from complete, but it does run in VBXE 80 column mode.

[Stephen]

Kr0tki, on Mon Apr 4, 2011 9:06 AM, said:

Stephen, on Mon Apr 4, 2011 5:52 AM, said:

To the best of my knowledge, there is only one version. The SDX driver can make the XEP80 switch between PAL and NTSC modes via command line switch.

Thanks. Do you know where I can obtain the SDX driver (and possibly some instructions)?

Stephen, on Mon Apr 4, 2011 5:52 AM, said:

I cannot answer your other two questions,

Yes you can Computing the character cell height is a matter of displaying a inverse-video character and counting number of scanlines it takes. Could you check it out in your free time?

Stephen, on Mon Apr 4, 2011 5:52 AM, said:

but I will say this. I have never found a display device that didn't completely "chop off" the 25th line of text.

Yup, I'm aware of that. 275 lines is more than a typical PAL TV displays ,which is about 260 lines.

I believe the driver is included on the standard cart image for 4.42 (I am at work now - I will verify this when I get home). It should be accessible via CAR:XEP80.SYS (it takes command line parameter of P for PAL, N for NTSC). You will want to add the line "DEVICE=CAR:XEP80.SYS" to your config.sys file.

I will get you the character size info as soon as I get home.

[Kr0tki]

Thank you very much! It's indeed included with SDX 4.42.

[Mathy]

Hello Kr0tki

It might not answer the above questions, but have you looked at the stuff I collected on the XEP80 on my special stuff page?

sincerely

Mathy

[Kr0tki]

Yup, I'm actually linking to one of your files in the first post

[Stephen]

Kr0tki, on Mon Apr 4, 2011 1:34 AM, said:

Hello,

I've got a few questions about the XEP80 interface. The data on the Net is somewhat confusing, maybe some could help me fill the blanks.

1. Are there two different versions of the XEP80, one for 50Hz displays and one for 60Hz displays? Or is there only one version that can be switched to either ow the two by software?
2. What is the character cell size in the text mode? There are conflicting reports - one says that the size is 7x10; another claims that the height is 11 pixels. 11 pixels would give 275 scanlines, which is too much for the NTSC standard. So I'm suspecting that the character cell size is different for 50 and 60Hz modes. Is it true?
3. Anyone knows what is the frequency of the XEP80's pixel clock? I need this to accurately compute the XEP80's pixel aspect ratio.

Well, to the best of my ability, it appears that the character cell is composed of 10 scanlines. An uppercase X is 7 scanlines, and in inverse there is one scanline above and two below. This is the same regardless of whether or not I had the SDX driver in PAL or NTSC mode. The X character is 5 pixels wide, with a space at either end giving a total size of 7X10.

[Kr0tki]

Thanks for your effort. So the screen height is actually 250 lines, that's still a huge amount of overscan but at least it fits the NTSC specs. However it bugs me that in 50Hz mode tou got the same result - 250 lines should be visible on most PAL TV sets, and I've seen many accounts from the PAL guys that they still get the screen cropped.

Now could anybody from the PAL land confirm if the character height is 10 or 11 pixels? I think one more account will be enough to resolve the issue beyond doubts.

EDIT: I've got an idea. Stephen, maybe in the 50Hz mode the XEP inserts a blank scanline every 10 lines, but you haven't noticed?

Edited by Kr0tki, Tue Apr 5, 2011 1:24 AM.

[Rybags]

Another thing - does it Sync at the same rate as equivalent NTSC/PAL ?

I'd assume it'd have to be close, especially since monitors back then weren't so tolerant of off-spec signals.

If it ran faster HSync, the lines would be packed closer together.