Teletext graphics finally make it on the Electron!
The Acorn Electron is the archetypal add-on computer; on its own it is a very simple no-nonsense 32K computer, but with the advent of shadow RAM, sideways RAM, disc interfaces and turbo upgrades, the machine is having a pretty good run for its money.
One thing has always been in the way of offering true BBC compatibility however... Teletext graphics.
Say the words "Teletext" to a hardened Electron user and their eyes will glisten over with thoughts of Prestel, Ceefax, Bulletin boards, more memory and a majority of BBC micro programs, including WORDWISE PLUS.
In the past the way around the Electron's inability to display Teletext was to either forget the piece of software and go for a rewrite (WORDWISE PLUS for the Electron and high score tables in games etc) or to "simulate" the graphic characters in software by creating a black and white facsimile - a method that has been quite successful, but nevertheless failing to put over the colourful effect!
At the first Acorn User show way back in 1984, when the Electron was shown for the first time to packed crowds, a small stand named Sir Computers (sadly, now defunct) was rumoured to have a Mode 7 card for the Electron. Ugly rumours were afoot that Acorn "asked" for the board to be taken down for fear of distracting the crowds at the launch. This was never substantiated, but I have a feeling that there is some truth to the story, no matter how small.
The launch went ahead, the Mode 7 board died a death.
It is now 1988 and a small cardboard box arrived in the post without warning, it was heavily wrapped and was oblong - little did I know that, inside this unassuming box, was another box marked the JAFA SYSTEMS MODE 7 BOARD.
This board, whilst having absolutely nothing to do with the original Sir board, nevertheless sets out to create exactly what we all saw four years ago; it's been a long time coming folks, but at last the answer to every Electron users' prayer is here, a realio trulio Mode 7 board!
Right! The board is about the same size as the SLOGGER ROMBOX+ and is about the same width so it sits neatly and tidily on the back (and it bolts into place as well!). On the top of the box is an enigmatic square green button which replaces the BREAK key on the Electron (as this will BREAK into Mode 7). Out of the side is a new RGB socket, a new TV modulator and a connecting cable. Other than that, there is nothing else to the board, there is a sideways ROM built into the board so there is no messy cartridge slot required, and it even works off of the Electron's existing power supply... a nice touch that one.
Plugging in the board (correctly connection the monitor and the Elk) and powering up gives... absolutely nothing! Remember I said there was a Sideways ROM inside the board? Well, the ROM has to be invoked by typing *MODE7ON or OFF (I sigh with relief!) - a companion TEST command displays a seven-colour Teletext bar down the screen, similar to broadcasting test signals... Things are looking good.
First of all I pull out some undemanding Mode 7 software, an educational package - hey, it works! All of the proper Teletext characters are here - there are the flashing ones; the dotted effects. The trial program I loaded (from disc) works fine, albeit slowly, and there is at last, enough memory to start thinking about writing BBC BASIC programs on the Elk without having to use Shadow memory or a Second Processor.
Let's be a bit sneaky bow... I unplugged my copy of WORDWISE PLUS from the Beeb and shoved it into a spare socket on the SLOGGER ROMBOX+, I entered *WORDWISE and there it is, that lovely cyan and yellow menu! I loaded up a few segment files and they all work properly, again a bit slowly. There is an additional command in the Mode 7 ROM that enables the Electron's function keys and turns them into proper BBC Micro type function keys... this is fun!
Time to speed things up now... I plugged in the 6502 Second Processor and again, 6502 second processor programs work with the Mode 7 board, as does the SLOGGER MASTER RAM BOARD and Shadow RAM - is there no end to the compatibility of this board?
I plugged in the ANDYK RS232 INTERFACE and plugged in a specially-modified version of the MICRONET ROM, plugging in my old Beeb Modem (an Apollo model). I dialled up and got up on Prestel, mailboxes everywhere (Hey guys, you won't believe this, but I am sending this to you using an Electron with a Mode 7 card!) A few hours (and no doubt a killer of a phone bill) later, I logged off of my last bulletin board) and happily went to bed.
Next day, I woke up bright and early ready to read the Ceefax pages using Morley's Electron TELETEXT ADAPTER and a Modified Morley ROM - I scan the international news pages, I have a quick look at the share prices between gulping down my first coffee of the day and it's time to do some Telesoftware downloading!
This is where the Electron really begins to look impressive; plugged into a SOLIDISK FLOPPY/HARD DISC INTERFACE, I pulled all of the software for the Beeb straight down, fresh from the BBC transmitters and I started running the software...
Not all of the software on Teletext runs on the BBC Micro, but over the past four weeks I can say that 90% of the free software works on the Elk, all of it written in BASIC and none of it is Beeb-specific (i.e. Master only) ... Hell, even a few of the utility ROM images worked as well!
The Morley's TELETEXT ADAPTER isn't supposed to work with the Jafa MODE 7 BOARD, but the engineer who created this board clearly understands that in order to make people want to buy his board, then he will have to supply software that makes use of Mode 7 - this is why he is currently negotiating with Morley Electronics (who make some very impressive tackle indeed) and Micronet for the rights to sell modified software using the board.
WORDWISE PLUS is a straight plug in and go job; there are no messy software "kludges" to be loaded, you can go out and buy a copy of the ROM and plug it in and start working - it's as simple as that!
Games are a bit different - The silly thing about the Electron is that because it has so little memory inside it, games are nigh on impossible to even load into it. Many programs have to be loaded in and assembled in order to run, and if you don't have enough memory, there is little chance of getting software to load at all!
This is no longer the case with the Elk and the Mode 7 board; all of the Acornsoft titles loaded and assembled (not all executed), but the memory was there - of the games that did load (SNAPPER, MONSTERS, etc) the title screens were all in glorious Teletext and the high score tables were all there in their full glory - even putting on a Turbo Board made the games playable!
The next test was to load in ISO-PASCAL, write a quick program to do something silly and watch it work in Mode 6 - fine, the compiler runs happily, now we'll change things so that the program runs in Mode 7 and run it again. The program runs faster! This is because the screen is written to quicker using the Mullard Mode 7 chip than with the ULA on the Electron's board.
This is a common feature and something to keep in mind when writing software for the Beeb, Mode 7 has a far higher priority as a screen driver because it has its own processor (the Mullard chip) and works off its own bat (i.e. not the ULA).
I have tried the Mode 7 board on nearly every piece of Electron hardware and software I could get my hands on and most of it worked - if it required the use of Mode 7!
Interestingly enough, some Electron software actually gave me a Mode 7 screen on the high score tables, which is weird to say the least! I can only assume that either an old BBC Micro code was left in after the conversion, or it was written to take into account a possible Mode 7 upgrade.
This is a quality product - well made, and is compatible with a majority of Elk products, including the Plus 3 and the Plus 1 - buy it.
The Mode 7 board costs £89 inclusive and is available from Jafa Systems.