Third party Apple ][ expansion cards

[Everlevel]

The Apple serial card designed by David N Anderson for Namal Electronics in 1983 supported not only RS232 but also 20mA loop.
This was one of a range of cards from Namal Electronics, Cambridge, England designed by David Anderson for the Apple ][. Like others from this supplier drivers were available to allow printing from CP/M if a Z80 card was installed as well as the native Apple DoS.
Jumpers (at the top of the board) could be used to define handshaking type and interface required. This card used a quad opto isolater to protect the 5 volt logic from the 24v RS232 and to isolate for 20mA loop use.
It stands today as a significant historical artifact reflecting:

• British engineering innovation in American hardware ecosystems,
• The evolution of custom Apple II peripherals in the early 1980s,

 

[Everlevel]

This Apple ][ expansion card also had 4k of onboard ROM (2732) which could be accessed using a sideways memory techneque.
Despite its advanced capabilities, the Super Clock 1 was not widely known—likely due to its limited production and targeted industrial clients. It stands today as a significant historical artifact reflecting:

• British engineering innovation in American hardware ecosystems,
• The evolution of custom Apple II peripherals in the early 1980s,
• A rare example of firmware-integrated sideways RAM in Apple II hardware.

This board demonstrated early hybrid memory design on the Apple II, allowing dynamic memory paging outside Apple’s standard architecture. It's one of the only known Apple II peripherals to use Sideways ROM/RAM model—and to successfully integrate them with real-time timing logic. Its potential applications ranged from computing environments to NATO Maintenance and Supply Agency operations in Luxembourg
One of a couple of expansion cards designed by David N Anderson, Cambridge, England in 1982 for Namal Electronics.
Other cards were Serial card that supported RS232 and 20mA loop and parallel expansion card supporting parallel print (centronics) and could be used for general control.

 

[Everlevel]

More notes on the Super clock card :
Sideways memory was developed in 1982 to overcome a problem with the Apple ][ computer expansion slots.
Due to the addressing limitations of the 6502 and most 8 bit microprocessors of the day, total addressable memory was limited to 64k bytes.
The Apple ][ tried to address this problem by having a shared 2k of memory reserved for use by the 6 expansion slots along with their individual 256 bytes of on card memory. In many cases the was ok but with video expansion cards this caused a problem which showed itself as screen flicker or sometimes a blank screen when the shared memory was switched in and out of use by another expansion card.
With the Super Clock 1 card from Namal electronics, designed by me Dr David Anderson, this was an unacceptable problem as one of the functions on the card was to display the current time at the top of the screen.
A method was needed to have more than the 256 bytes of Memory for the expansion slot without using the 2k shared memory.
By using a 6522 Versatile Interface Adapter (VIA) with its 2 x 8 bit I/O, It is possible to use one set of this PIAs outputs to control the clock chip and the second set of outputs to extend the memory addressing on the expansion card.
Another aspect of the 6502 processor is its Indirect addressing. As part of the instruction set of the 6502 processor as well as the standard jump (JMP) 3 byte instructions, the indirect addressing allowed a 2 byte JMP instructions known as branch (BRA). These are jumps that are limited to the current 256 byte page leading to coding for a 256 byte memory page to be only 2 bytes and, therefore, extra efficient.
How it works.
By using the 6522 PIA to control the sideways switching of the memory, the firmware code in the ROM can be programmed thus.
Your code
.
.
.
Ending the page with:
PHAPush A; temp store the A register
LDA #Load A with the next page number; the pages don't have to be in sequence
STA Store this page in the 6522 PIA, this will make the RAM shift sideways the continuing code on the next selected page. This is why it is important to have this code line up at the same relative memory addresses.
The following code is at the same memory position but on a different page that has been slid sideways.
PLArestore A
BRA #00branch to start of this new page and to continuation of your code.

 

[ajacocks]

Everyone, I spoke directly to @Everlevel. They are not an AI.

@Everlevel, you might want to introduce yourself to the folks here.

- Alex

 

[cjs]

Everyone, I spoke directly to @Everlevel. They are not an AI.

But if he were an AI, how would he know? :-) I was recently informed that, as indicated by my regular use of em-dashes, that I'm an AI, and I had no idea. (I took it badly at first, but I am slowly becoming resigned to my new position in life, or I guess lack thereof.)

A rare example of firmware-integrated sideways RAM in Apple II hardware.

It's one of the only known Apple II peripherals to use Sideways ROM/RAM model...

Sideways memory was developed in 1982 to overcome a problem with the Apple ][ computer expansion slots.

Well, no. "Sideways ROM" appears to be the BBC Micro term for what's much more widely known as bank switching, and this was introduced to the Apple II at least as early as Apple's Language Card, released in 1979. The Language Card was also incredibly common; many, possibly most Apple II+s sold from about 1980 onward had one. (And many Apple IIs got them as an upgrade, as you need it or a similar ROM card to run Applesoft BASIC on the II.)

For an example of bank switching in the 256-byte areas allocated to each card slot, you can look at, e.g., the Frob card that was recently discussed in this forum.

It is unusual to have a 6522 to support bank switching when it can be done so much more cheaply than that, but I'm guessing this card used a 6522 anyway for the timers, and so the extra logic in that used for the bank switching came essentially free.

 

[Everlevel]

Hello, I'm Dr David Anderson for the last 30+ years I've run my IT business Everlevel Ltd here in England. I'm semi retired and looking to spend some of my now spare time archiving tech stuff from my past.

 

[Everlevel]

But if he were an AI, how would he know? :-) I was recently informed that, as indicated by my regular use of em-dashes, that I'm an AI, and I had no idea. (I took it badly at first, but I am slowly becoming resigned to my new position in life, or I guess lack thereof.)




Well, no. "Sideways ROM" appears to be the BBC Micro term for what's much more widely known as bank switching, and this was introduced to the Apple II at least as early as Apple's Language Card, released in 1979. The Language Card was also incredibly common; many, possibly most Apple II+s sold from about 1980 onward had one. (And many Apple IIs got them as an upgrade, as you need it or a similar ROM card to run Applesoft BASIC on the II.)

For an example of bank switching in the 256-byte areas allocated to each card slot, you can look at, e.g., the Frob card that was recently discussed in this forum.

It is unusual to have a 6522 to support bank switching when it can be done so much more cheaply than that, but I'm guessing this card used a 6522 anyway for the timers, and so the extra logic in that used for the bank switching came essentially free.

Well yes, I showed the technology to Acorn, which was just down the road from me. My contact there at the time was John Cole but I also knew Hermann Hauser and his wife Pam. Hermann was the joint founder of Acorn.

I don't know the Frob card. If by language cards do you mean Z80 cp/m card and other second processor cards?

 

[vwestlife]

Sure, not everything that includes em dashes was AI-generated, but it's impossible to get AI to generate text that avoids all use of em dashes, even when you specifically instruct it not to:

The Em Dash Dilemma: How a Punctuation Mark Became AI’s Stubborn Signature

Almost a year ago, I stumbled into a weird rabbit hole, trying to outsmart AI. Since I moderate a number of very large subreddits, I…

medium.com

And bullet point lists are another giveaway of AI-generated text.

 

[Everlevel]

I did a lot of work with the Apple ][ but my first computer was the UK101 in the US it was called the superboard 2. Singleboard 6502 based.

As I did all of my early work on the UK101, I based my degree work on Ohio Scientific Computers.

 

[Eudimorphodon]

I don't know the Frob card. If by language cards do you mean Z80 cp/m card and other second processor cards?

No. In the Apple II universe "Language Card" refers to the 16K RAM board that became essentially standard equipment on disk-based Apple II's by the early 1980's. (It was introduced in 1979.) The Apple II has built into it a system that lets a card override the built-in ROM sockets, and the Language card leverages that to provide a chunk of RAM that can on a semi-granular basis be swapped in and out. If you've ever booted an Apple II+ or IIe (the IIe essentially has the "Language card" built-in) with the standard DOS 3.3 master you'll see a message about it loading Integer BASIC into the language card. (And, actually, if you have an original II that still has Integer on the motherboard but has the language card installed, a rare but possible configuration, it's possible to load Applesoft into the card instead.) User programs that themselves can make use of more than 48K of RAM also directly leverage it. (The card was originally introduced for use with Apple's Pascal/P-System programming environment, which was a really tight fit in 48k.)

(Before the RAM-based language cards Apple sold a Firmware card that literally had a toggle switch on it to allow you to have both Integer and Applesoft in the same system. Here's a modern recreation of that.)

Kind of surprised you don't recognize "Language Card", since, again, by the early 80's the "standard" Apple II configuration targeted by most disk software was a "64K Apple II Plus", which was actually a 48K Apple II plus (or upgraded II, only difference is the ROM chips) plus said RAM card.

 

[cjs]

but it's impossible to get AI to generate text that avoids all use of em dashes, even when you specifically instruct it not to

That must be it. I also find it impossible not to use em dashes—even when people instruct me not to.

And bullet point lists are another giveaway of AI-generated text.

Oh, that tears it! I just checked my personal documentation repo and counted 7414 bullet list items.

I don't know the Frob card. If by language cards do you mean Z80 cp/m card and other second processor cards?

No, I mean the Language Card from Apple, introduced in 1979, that expanded it to 64K RAM and, in the earlier versions, added the Autostart ROM as well. You can find some information on it here, including links to the schematics and manuals. Here's the memory map from Appendix C of the manual.



I'm rather surprised you never had one, though I suppose it might not be so rare for early 48K Apple II+ machines that never got upgraded. (And I'm not familiar with typical European configurations; I grew up in Canada.) But a number of demos that Apple distributed with their system wouldn't run without a Language card because they were written in Integer BASIC.

On the IIe and IIc the language card was integrated into the system, though still using the same banking scheme, and without the extra bank of ROM at $F800-$FFFF.

The Frob is a ROM emulator and development system for the Atari 2600. It was discussed and reverse-engineered in this thread, and the disassemblies, schematics and a theory of operation can be found in this repo. It's quite a neat little card, I feel, though I'm probably heavily biased since I put a fair amount of work into helping to figure it out. (I'm the one that wrote the theory of operation for it, and I welcome comments. I don't feel it's as clear as it could be.)

 

[Everlevel]

Ah I think I know the card your referring to. We had a slightly different version of the Apple ][, the Apple ][ euro plus. Different video and firmware setup. The IIe had a different 80 col card (extended video card ?) which had a version with extra memory. I may need to dig out my IIe and refresh my memory. Things were changed name and marketing wise for the UK (and europe) markets, video was PAL, keyboards were different also. I don't think the Frob ever made it to the UK

 

[Eudimorphodon]

We had a slightly different version of the Apple ][, the Apple ][ euro plus. Different video and firmware setup

So far as I’m aware EuroPlus-es are basically identical to US Plus-es other than eliminating color (unless you add a PAL encoder board) and using PAL video timing. You’d still use the same Language card. But, eh, I suppose if you bought one early enough it might not have been the standard bundle yet.

The IIe had a different 80 col card (extended video card ?) which had a version with extra memory

If you pull the 80 column board out of a IIe it becomes essentially an Apple II+ with a language card. (16K of the 64K it has on the motherboard are bank switched according to Language card rules.)

 

[vwestlife]

If you pull the 80 column board out of a IIe it becomes essentially an Apple II+ with a language card. (16K of the 64K it has on the motherboard are bank switched according to Language card rules.)

Plus lowercase text and a much better keyboard.

 

[Everlevel]

No PAL encoder board. Always PAL colour direct from the motherboard

 

[vwestlife]

No PAL encoder board. Always PAL colour direct from the motherboard

"The Europlus did not output color on its own, it was strictly monochrome 50Hz out of the box. The Europlus could be fitted with the PAL Color Encoder Card in Slot 7 to translate the pixel patterns of the Apple II graphics modes to represent the colors that would have been displayed on an NTSC display on a PAL display."

Apple II Composite Artifact Color - NTSC, PAL and Filters

Vintage computers and retro gaming

nerdlypleasures.blogspot.com

 

[cjs]

Yeah, I think the Apple II would have required some fairly drastic changes to the motherboard if were going to produce PAL off the motherboard directly. The colour generation circuitry is very NTSC-centric, being pretty near the simplest way possible to add NTSC colour to a monochrome CVBS signal.

 

[Eudimorphodon]

"The Europlus did not output color on its own, it was strictly monochrome 50Hz out of the box. The Europlus could be fitted with the PAL Color Encoder Card in Slot 7 to translate the pixel patterns of the Apple II graphics modes to represent the colors that would have been displayed on an NTSC display on a PAL display."

Apple II Composite Artifact Color - NTSC, PAL and Filters

Vintage computers and retro gaming

nerdlypleasures.blogspot.com

Yep, this. The Euro versions of the IIe and IIc also couldn’t do color without add-ons. (A very rare one in the case of the IIc.)

 

[vwestlife]

There was also the "International NTSC" version of the IIe, which output NTSC color, but at a refresh rate of 50 Hz. Apple sold it with a 240-volt, 50 Hz version of their NTSC color monitor. Connected to a PAL monitor, it would sync up correctly, but not display any colo(u)r.