★ HARDWARE ★ PERIPHERIQUES - INTERFACES ★ INTERFACES CIRKIT|Amstrad Computer User) ★ |
| Interfaces CIRKIT | Hardware Peripheriques - Interfaces |
It all adds up Trevor Cummings contemplates a few CPC add-ons and delves into a pack of cards. For a number of years now there have been several CPC add-ons lurking around in the background. Their existence hasn't been widely known because they haven't been generally advertised in our magazines. To find them, you almost have to bump into them by accident. And that's just what I did a while ago. There's a Romboard, an RS232C port and a 8-bit printer and parallel port and their importance to us is about to be realised. Cirkit, who make them, are a similar company to Maplins in that they both produce do-it-yourself projects for the electronics enthusiast, both supply parts for one's own projects, both sell ready made units and both sell through their catalogues which we can buy from places like W.H. Smiths. Incidently, the new catalogue is due out just about now. The significance of the Cirkit addons is twofold. Firstly, we have just seen the demise of the DkTronics real time clock with general purpose I/O port and, secondly, Pace's RS232C serial interface is about to bite the dust. Pace still have some left but no more are being made. The idea of a real time clock is probably gone forever for the CPC but the I/O port, together with an 8-bit printer port, is one of the Cirkit products. So two of these add-ons might well fill the gaps left by those that have died. The first tiling that struck me about the HS-S1 RS232 card, and its software in particular, was its similarity to the Pace version. Soon afterwards the reason became clear. Both interfaces were designed by Honey soft. This prompted another thought. It has been generally believed that the Pace version was the only RS232 which actually used Amstrad's specified serial port addresses and, therefore, the only one to work happily in CPM with such comms programs as the very popular MEX. I figured the chances were great that the HS-S1 would also use” the specified addresses so I set it up to run Mex. No problem. I was straight into Micronet without so much as a “wot, no Pace?” message appearing on my screen. So, while the others ‘in the know' are weeping and wailing over the loss of the Pace device, I am busy writing a program to flash “who's a clever boy then?” all over my screen. Gordon Bates, eat yer heart out! << The HS-SI Dual Channel Series Card. There are differences between the tw'o though. Some favour one and some the other. Not least of these is the price. The Pace version costs around the £55 mark while the Cirkit variety costs £34.44 but Pace's has its software built in whereas Cirkit's software is £6.60 extra on tape and £10.81 extra on disc or ROM. The ROM version would also need a Romboard. As I have already said, the software is very similar but there is an important difference. Both make use of bar commands allowing the user to write his own comms software for whatever purpose. For instance, the command |CWRITE < string > will send a string of date to the RS232 port and out down the telephone line if connected. |CREAD will read a string from the port. With these and other commands, comms programs can be written in Basic. But as well as this, both viewdata and scrolling software, which gives the instant ability to access bulletin boards, Micronet. Microlink, etc., is integrated into Pace's Commstar software whereas Cirkit's software has no such facilities. The closest it gets is with the TERMINAL command which, when used after |OPENing a serial channel, does allow the computer to go straight on-line. However, it is somewhat basic and has none of the built-in facilities such as printing the screen, saving the buffer offered by Commstar and other comms programs. For serious ready made comms software we need to look to other programs. That seems to make the Cirkit device look like the poor relation, doesn't it? But it isn't. Consider this. Pace's interface is sold complete with Commstar whether you like it or not and a great many comms users don't like it. They use Mex or the Cage ROM for preference. The Cage ROM costs around £30 but Mex is Public Domain and virtually free. Now we can see Cirkit's device as an RS232 which uses the correct serial addresses and for which we can get free software. We don't have to buy software that we might not want. If we do want to experiment and write our own, then the ready made bar commands software is available and at a very good price. Another difference between them is that Cirkit's has two serial channels which can be used simultaneously while Pace's has only one. The second Cirkit channel consists of just two lines - transmitted data and received data so hardware handshaking isn't possible. Most of us would probably only use one channel but the second one is there if needed. Because of its legal addresses, it does look as if the HS-SI wall step into the hole about to be left by Pace. HS-RX1 ROM Expansion Card. >> Known to most of us as a romboard, the HS-RX1 Rom Expansion Card is just one of the half dozen or so boards available for the CPC and, like each of the others, it has its own merits, not least of which is its size. Measuring about 4" x 3", it can hold up to four standard ROMS such as Protext, Utopia, DOS ROM for megadrives and of course the ROM version of the RS232C software. With such ROMs connected, the programs they contain are instantly available at the press of a few keys and take virtually no time to load. The 464 can have up to 7 ROMS attached, including the disc drive ROM, and the 6128 can have 15. The HS-RX1 has a link which allows the user to set it for the bottom half (ROMs 0 to 7) or the top half (8 to 15) and, within those halves, each ROM can be set to any number. I think we are all pretty familiar with ROMS so there's not a lot more to say about the board except this. For its four socket size its £22.94 price tag fits in quite reasonably with its competitors but, and it's a big but, if it is bought together with one of the two other add-ons, then it can be bought at half price) £11.47. Now that's not bad, is it? Remember, you heard it here first. I've saved the HS-P1 Parallel and Centronics Card until the last because I find it the most interesting of all three. Possibly the most significant thing about it, as far as most CPC users are concerned, is that it is an 8-bit printer port. That's not all it does but I'll come to the rest a little later. Remember the 8-bit printer port project we did a few months ago which allowed us to access the ‘high' graphic character sets in our printers? This card does the same thing. Unlike ours though, it doesn't use the same printer port address and it attaches to the computer's expansion socket, not the printer socket. These two facts are significant because it means that two printers can be connected at the same time and each can be selected by a single command. Those who can afford it can have a dot matrix and a daisywheel printer fitted together and choose which one to send the printer output to. You could, in fact, have three printers connected but that's going a bit far, isn't it? << HS-P1 Parallel and Centronics Card. The HS-P1 is a dual 8-bit parallel card and as well as the edge connector for the printer it has a 26 way IDC connector for other general purpose in/out work. Both ports have full handshaking available and can have each bit configured as input or output. Hence, up to 16 different external devices can be controlled through them. The instruction book provided contains several application suggestions including the control of a turtle. Like the RS232, the software is optional and can be bought on tape, disc or ROM. Also like the RS232 it is in the form of bar commands which are simple to use from Basic. Some of them are - put, get, write and read. The :PIO.PRINT,(n) is perhaps the most useful as it allows printer selection, a choice of 7 or 8-bit mode and the type of handshaking. For instance :PI0.PR1NT,2 will cause all printer output to be 8-bit, BUSY handshaking only and directed to the HS-P1 port. And that will continue until a computer reset or until another such command is issued. If the 2 had been a 1 then the output would go to the CPC's normal 7-bit printer socket. For general in/put applications the commands are extremely useful and likewise for 8-bit printer use. But the software isn't essential. The book does supply technical information including the I/O addresses used and a simple bit of machine code, rather like the program that ran our own 8-bit port, is all that is needed to intercept and redirect printer output. Watch this column in the very near future for a program to run the 8-bit port. After that, as they say, yer on yer own. Pin-outs of both port are also given so the technically minded among us would have no difficulty in making full use of the ‘control' aspects of the card. At £22.94 the HS-P1 is an excellent buy if you have more than one printer or if you want to control external devices from the computer. The software is extra - £4.44 on tape, £8.74 on disc or ROM. But let's not forget KDS' 8-bit port which includes its type-in software at around £19. It's a case of horses for courses really. The KDS device will only ever be an 8-bit, printer port and, if that's all you need, then it's the one for you. If you aspire to other things then the Cirkit card doesn't cost too much more. All three cards are made to the same 4" x 3" size and all connect to the computer's expansion port (disc drive port on the 464) via a short length of cable. They each have a through edge connector so that other peripherals can be added and they are sold uncased. This last point needs a mention. When connected to the computer, the boards lie flat on the desk with their pin sides down. If your computer is moved frequently then your desk could become slightly scratched as the boards slide across it. This is easily overcome by fitting some little stick-on-feet to the undersides. Cirkit can supply them at 48p for 8 - stock number 21-10030. Alternatively, the boards have a good sized hole in each comer and many methods can be found of using them to prevent the pins resting on the desk.
| ||||||||||||||||||||||||||||||||||||||||||||||||||
