Apple IIe 80 column mode basically unreadable - what am I missing?

[owensct]

Hi All,

So I have a Apple IIe that I have been playing around with. It came with a Microsoft Premium Z80 CP/M card. I finally got the CP/M boot disk down loaded and booted it to CP/M. CP/M runs in 80 columns and it is almost unreadable. Thinking that it was the box I am using to hook the Apple up to a modern LCD monitor I plugged it into the composite port on my Commodore 1902A monitor and its no better. I have tried switching to 80 column mode in Apple Basic and it is just as unreadable. 40 Column seems to work fine. The Z80 card has an 80 column mode, so maybe it a problem with the Z80 80 Column. I have a regular 80 column card, but I haven't tested it out yet to see if it performs any better. I've also tried different composite cables and there is no significant difference.

Is this normal for Apple IIe in 80 column mode or am I missing something/doing something wrong? I know on the old Commodores trying to display 80 columns on a composite monitor was so bad it wasn't supported, but since Apple supported it I figured they had a way around it.

Any input would be greatly appreciated.

Thanks

Gordon

 

[SomeGuy]

Perhaps post a photo of how it looks?

80-column mode pretty much did suck on composite color CRTs. It looked best when using a monochrome CRT. Chances are an LCD TV is treating it as a lower resolution "color" image, even if it lacks color.

Also, on a IIe, the 80 column mode is built in. You must install a memory card to have access to 80-column mode, but the 80-column hardware is already in the video hardware.

 

[Eudimorphodon]

80 column composite video is usually pretty hopeless, that's just how it is. That's why most Apple II's in business settings were paired with green monochrome monitors. To get around the problem to some extent the "ColorMonitor IIe" that Apple sold for those machines had a switch on it to throw it into a monochrome mode as needed for text applications.

If the Commodore 1902A monitor you have supports separate "Chroma" and "Lumina" inputs (Ala a C64, aka, "S-Video") something you can try is connecting the output from the Apple II to the Lumina input instead of composite. That should kill most of the color fringing and basically make it act like an Apple monitor with the color killer button pressed. I've displayed remarkably clear (considering) grayscale 80 column text from the composite connector of a Tandy 1000 on a Commodore 1702 monitor by connecting it like that.

 

[VERAULT]

Good point.. Was the 1902 in mono or color mode? In color mode the text would not look great. Basivally there is no reason to be in color when using the cp/m card.

 

[owensct]

Hi Guys,

Yeah I pretty much figured 80 col composite was a lost cause. I vaguely remember attempts to do 80 col composite on the Commodore 64 and it was bad, a company (Hesware I think) came out with an 80 col cartridge for the C64, (I had one) and it was pathetic, which is why when Commodore came out with the C128 they did the 80 column mode differently. The 1902A is a Digital RGB and Luma/Chroma video monitor with female 8-pin DIN connector, (for Commodore PC's CGA and C128 80-Col mode) female 6-pin DIN connector, (C64 and C128 40 col) 1x RCA connector, (to hook up a VCR). It also has a switch to put it in monochrome (green). No S-Video unfortunately.

Well At least I now know it just 80 col composite and not a problem with the Apple. I guess I can mess around with the 1902 to see if I can improve the display. Maybe I can improve the image as I really want to play around with Apple CP/M. CP/M was what I cut my teeth on back in the day besides mainframes. Plus I really don't want to buy another vintage monitor. Hopefully I can find a way to improve the output on the LCD or do the same on the 1902A and share the monitor between the two. 30 minutes of staring at that screen at my age and I'll have a ripping migraine, lol.

BTW the picture of the 80 col on the 1902A is way more, (and I mean way more) readable in the picture than it is on the actual screen. In person it is brutal on the eyes.

Thanks for the Info

Gordon

 

[gertk]

What kind of cable did you use ? A good quality coaxial cable could improve things a lot.
Do not use composite video input as its bandwidth is limited. The Y (Luma) input should give a much better pictue in combination with a quality video (coaxial) cable.

 

[VERAULT]

Im going to disagree with you. I use 80 col composite. But as mentioned previously, I use it on monochrome monitors and the text looks completely fine. I only use my Commodore monitors for Color, I use monochrome on everthing else, just easier on the eyes since I mostly do text. I use a Zenith datasystems green screen on my work bench. I think you will change your tune if you use a monochrome and 80 col mode. (not monochrome mode, actual monochrome)

 

[Eudimorphodon]

The 1902A is a Digital RGB and Luma/Chroma video monitor with female 8-pin DIN connector, (for Commodore PC's CGA and C128 80-Col mode) female 6-pin DIN connector, (C64 and C128 40 col) 1x RCA connector, (to hook up a VCR). It also has a switch to put it in monochrome (green). No S-Video unfortunately.

The "C64 and C128 40 col" connector is the equivalent of S-Video, IE, they're both the same thing: "Lumina", which is a monochrome grayscale composite signal, and a "Chroma" signal on a different wire instead of mixed into a color composite signal. If you make a breakout cable that lets you connect the IIe to the Lumina input on the DIN jack it should give you a signal *almost* as clear as an actual monochrome monitor; Mono monitors are still sharper because they don't have to make white pixels out of three different phosphors sorted by a shadow mask, but it should be clearer than via the composite connector.

(The reason the composite connector is problematical is the dot-clock of the Apple II by necessity is a multiple of the NTSC colorburst frequency, which means that even if the colorburst itself is shut off on the computer side (which it is by default in the text modes) the monitor is still essentially passing the 14mhz-ish stream of dots you're sending to it through a filter that looks for phase shifts at a 3.58mhz cadence, which limits the effective bandwidth significantly, and there is also the possibility of the high-res dots getting interpreted as color shifts even without the formal colorburst.)

 

[VERAULT]

The "C64 and C128 40 col" connector is the equivalent of S-Video, IE, they're both the same thing: "Lumina", which is a monochrome grayscale composite signal, and a "Chroma" signal on a different wire instead of mixed into a color composite signal. If you make a breakout cable that lets you connect the IIe to the Lumina input on the DIN jack it should give you a signal *almost* as clear as an actual monochrome monitor; Mono monitors are still sharper because they don't have to make white pixels out of three different phosphors sorted by a shadow mask, but it should be clearer than via the composite connector.

(The reason the composite connector is problematical is the dot-clock of the Apple II by necessity is a multiple of the NTSC colorburst frequency, which means that even if the colorburst itself is shut off on the computer side (which it is by default in the text modes) the monitor is still essentially passing the 14mhz-ish stream of dots you're sending to it through a filter that looks for phase shifts at a 3.58mhz cadence, which limits the effective bandwidth significantly, and there is also the possibility of the high-res dots getting interpreted as color shifts even without the formal colorburst.)

Oh well here is my question. Does the CP/M card create its own 80 col display using hardware on the card or does it use the 80/col capabilities (if any) of the apple II. I have seen apple II+ and IIe machines WITHOUT 80 col cards have perfectly readable 80 col CP/M text with only the softcard / CP/M card installed. Again I dont know how it works but I get the feeling the CP/M card (or some of them) render thier own 80 col display. Take what I say with a grain of salt I have nothing to back this up except my memories.

 

[resman]

The Microsoft Premium CP/M IIe card plugs into the AUX slot and provides the same functionality as the IIe 64K RAM card plus the Z-80 functionality used by CP/M. As such it behaves just like any IIe with an AUX RAM card for the sake of 80 columns. A regular color composite monitor doesn't have the bandwidth to display 80 columns nicely. The AppleColor IIe and IIc composite monitors will increase their display bandwidth when they senses the color burst is disabled to improve the display of the monochrome 80 column text mode. Not as nice as a real RGB monitor or monochrome monitor, but a reasonable compromise if you aren't using 80 column text mode all the time.

 

[VERAULT]

Resman, how common/rare are those Microsoft Premium Softcards. Just Curious.

 

[Eudimorphodon]

Oh well here is my question. Does the CP/M card create its own 80 col display using hardware on the card or does it use the 80/col capabilities (if any) of the apple II. I have seen apple II+ and IIe machines WITHOUT 80 col cards have perfectly readable 80 col CP/M text with only the softcard / CP/M card installed. Again I dont know how it works but I get the feeling the CP/M card (or some of them) render thier own 80 col display. Take what I say with a grain of salt I have nothing to back this up except my memories.

So far as I'm aware on a II+ you either need a separate 80 column card or you're using a fancy CP/M card that also has a video generator on them. (Which considering the huge number of cards they made for the Apple II I certainly wouldn't rule out.) The plain ol' minimal Microsoft Softcard-type Z80 card didn't do 80 column on its own. Here's a brief Infoworld review that specifically says you need an 80 column card or a serial terminal if you want better than 40 column.

Those "Premium Softcards" for the IIe weren't really anything special in that regard, they essentially were just the guts from a regular Softcard grafted onto a clone of the normal AUX-slot Apple memory card that enables a IIe to do 80 column internally. The IIe's 80 column capability emulates the standard "Slot 3" interface used by Videx cards (the actual hardware is completely different, but most programs access things through the ROM driver so it's okay) so a regular Softcard in a IIe with the 80 column/128k board can also do 80 columns. The "Premium" card just saved a slot.

 

[resman]

Resman, how common/rare are those Microsoft Premium Softcards. Just Curious.

Not exactly sure. My guess is they didn't sell a lot - there were better options by then. A few things of note:

1. The software mine came with didn't play will with MouseText, so it was before the Enhanced IIe came out. There was a patch I downloaded from the Apple CP/M group that fixed it.

2. It only ran at 2 MHz. Others like the PCPI were faster.

3. Used the AUX slot so you couldn't opt in a RAMWorks card or RGB card.

 

[gertk]

Im going to disagree with you. I use 80 col composite. But as mentioned previously, I use it on monochrome monitors and the text looks completely fine. I only use my Commodore monitors for Color, I use monochrome on everthing else, just easier on the eyes since I mostly do text. I use a Zenith datasystems green screen on my work bench. I think you will change your tune if you use a monochrome and 80 col mode. (not monochrome mode, actual monochrome)

I totally agree with you when using a monochrome monitor as these do not have filtering. On a color monitor using the composite input (as Gordon mentioned he used) you are severely limited by the color decoding and filtering circuitry. It will be less than 4 MHz bandwidth.
On a monochrome monitor you can easily achieve over 20 MHz bandwidth.

 

[owensct]

Guys,

Interesting information and a lot to absorb thanks for the help. Now I just need to do some additional research.

Gordon

 

[shirsch]

Those "Premium Softcards" for the IIe weren't really anything special in that regard, they essentially were just the guts from a regular Softcard grafted onto a clone of the normal AUX-slot Apple memory card that enables a IIe to do 80 column internally.

Not quite. The traditional Softcard shared host computer memory with the 6502 and was constrained to a clock speed that made this possible - effectively about 2 Mhz. The Premium Softcard IIe was a more conventional design that had its own 64k of onboard memory. The only Z80 add-on (that I'm aware of) with built-in video was the DRI "Gold Card". Those are interesting, but extremely rare.

 

[BulbulatorMacher]

1. The software mine came with didn't play will with MouseText, so it was before the Enhanced IIe came out. There was a patch I downloaded from the Apple CP/M group that fixed it.

Sorry for responding after 5 years, but I can't send DMs yet, and this topic is what I'm interested in.
Was that Yahoo Apple CP/M group? Yahoo Groups have been closed in 2020. I've tried to, but was unable to find its contents on archive.org. Do you still have this patch?
I've been able to modify the standard image to work with MouseText myself. I could upload my patch, but I prefer to use the historical version if one exists. Besides, I'm not 100% sure if mine is correct - I've found a block of unused RAM and disk image and placed a patch there - about 20 bytes with respective JMPs.

 

[alank2]

80 column composite looks crisp and clean on a Tandy 1000 with a Tandy VM-2 monitor. It is probably the low dot pitch of a color monitor that is the issue.

 

[resman]

Sorry for responding after 5 years, but I can't send DMs yet, and this topic is what I'm interested in.
Was that Yahoo Apple CP/M group? Yahoo Groups have been closed in 2020. I've tried to, but was unable to find its contents on archive.org. Do you still have this patch?
I've been able to modify the standard image to work with MouseText myself. I could upload my patch, but I prefer to use the historical version if one exists. Besides, I'm not 100% sure if mine is correct - I've found a block of unused RAM and disk image and placed a patch there - about 20 bytes with respective JMPs.

Yeah, that was a while ago. I'd imagine your patches are similar. I'll look for the disk image, but make no promises - I'll have to dig through a bunch of floppies.

 

[Eudimorphodon]

80 column composite looks crisp and clean on a Tandy 1000 with a Tandy VM-2 monitor. It is probably the low dot pitch of a color monitor that is the issue.

FWIW, recently I experimenting with building an RGBI-to-Svideo adapter using an AD724 encoder chip, and the results were... interesting. On one hand it's a *huuuuge* improvement over composite, in that 80 columns is "readable"; what really was amazing was how well it could do one color text over a different color background, composite tends to be completely hopeless at that.

On the other hand, well, you can see clearly just how bad the dot pitch is on the Commodore 1702 monitor I was using for this in this shot:

One saving grace CGA has over the Apple II is the default CGA font uses 2 pixel wide vertical elements in most letters. The Apple II font is much scrawnier. As a result CGA's characters are clunky and a little blurry, but at least they're "solid". With the Apple II's skinny font a bad dot pitch can actually cause the characters to look like they're breaking up.