Category Archives: T2A2

DIY Projects, DIY Transputer interfacing, T2A2

T2A2

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Ok, here it is. The T2A2. What sounds like a robot from StarWars is actually a Transputer to Apple II interface. Its design is pretty much the same than its cousin, the T2C64, with the addition of some buffers to behave like a good citizen of the Apple-II bus. So this is how the little beast looks as of now (v0.5):

T2A_front

To use the Apple-II bus-connector of the 8Bit-Baby (another brainchild of mine), I had to shuffle the parts around a bit. On top you’ll see the same TRAM used on the T2C64… 20MHz T800 Transputer, 128KB SRAM. Right below it is an LS245 octal bus-transciever to handle signals like DevSel, R/W and A0-3. To its right its the IMS012 Linkadapter converting 8bit parallel bus into INMOS’ serial link-protocol. Below that, there’s the silver 5MHz oscillator to clock the IMS012 as well as the Transputer and another 245 to buffer the data-lines (D0-7). Finally on the left bottom there’s the CPLD which handles the Analyze, Reset and Error lines of the Tranputer as well as chipselect and such (Thanks to Mike for helping out on VHDL here!).

The picture above is the first Prototype and it’s finally working… even it’s a nightmare to look at its back side 😀

T2A_back

But because I’m a Commodore guy who wasn’t able to afford an Apple II in its hey-days I had to start from scratch and learn a lot…
That said, when I finally could afford an Apple II system, I went straight for the IIgs. I think IIgs is the perfect platform for an 8-bit Transputer interface given the amount of available/adressable RAM, native access to harddisks and a decent screen resolution.

Because of its simple design, the T2A2 should also work in any Apple-IIe etc. There’s no ‘firmware’, no EPROM. Just plain simple reading and writing to some (slot)specific addresses.
Due to its close relationship to the T2C64, programming is quite similiar. As a matter of fact I just slightly changed the examples I’ve used on the C64… which is the beauty of the idea.

So jump to the next post to see the first little test proggie in AppleSoft BASIC…

DIY Projects, DIY Transputer interfacing, T2A2

1st basic example

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Like with the T2C64, the CPLD on the T2A2 maps the C012 registers into the memory area of the used slot, using just 6 addresses starting at 0xc080 + (SLOT# * 0x10). So for e.g. Slot 4 this would be:

  • BASE        (0xc080 + (4 * 0x10))  = 49344
  • Data in:    BASE                   49344
  • Data out:  (BASE + 1)           49345
  • in-status:  (BASE + 2)           49346
  • out-status:(BASE + 3)           49347
  • reset:       (BASE + 8)           49352 (writing)
  • analyse:   (BASE + 12)          49356
  • errorflag:  (BASE + 8)           49352 (reading)

With this ‘knowlege’ we can start talking to the Transputer… and to make our first babysteps we’re using BASIC. It’s pretty much the same code as used on the C64 with the exception that there’s no “elegant” timeout handling due to the missing clock in AppleSoft, so you have to wait a bit longer until you get the printout in the end.
For details about what’s going on here, see the C64 page.

 10  PRINT "INIT TRANSPUTER"
11 BASE = 49344:IN = BASE:OUT = BASE + 1:IS = BASE + 2
12 OS = BASE + 3:RESET = BASE + 8:ANA = BASE + 12
13  POKE RESET,0: POKE ANA,1: POKE RESET,1
20  REM CLEAR I/O ENABLE
21  POKE IS,0
22  POKE OS,0
30  REM READ STATI
31  PRINT "I STATUS: ";( PEEK (IS) AND 1)
35  PRINT "O STATUS: ";( PEEK (OS) AND 1)
40  PRINT "ERROR: ";( PEEK (RESET) AND 1)
45  PRINT "SENDING POKE COMMAND"
46  POKE OUT,0
50  PRINT "O STATUS: ";( PEEK (OS) AND 1)
58 :
59  PRINT "SENDING DATA TO T."
60  POKE OUT,0: POKE OUT,0: POKE OUT,0: POKE OUT,128
61  POKE OUT,12: POKE OUT,34: POKE OUT,56: POKE OUT,78
70  PRINT "I STATUS: ";( PEEK (IS) AND 1)
79 :
80  PRINT "READING FROM T."
90  POKE OUT,1: REM PEEKING
100  POKE OUT,0: POKE OUT,0: POKE OUT,0: POKE OUT,128
110  PRINT  PEEK (IN); PEEK (IN); PEEK (IN); PEEK (IN)
128  DIM R(4)
129  PRINT "SENDING PROGRAM TO TRANSPUTER..."
130  FOR X = 1 TO 24
140  READ T: POKE OUT,T
150  WAIT OS,1
160  NEXT X
170  PRINT : PRINT "READING RESULT:"
175 C = 0: REM RETRIES
180  IF C = 10 GOTO 220
181  FOR X = 0 TO 5000: NEXT X: REM DELAY
189 ER = ER + 1: IF ER = 10 GOTO 220
190  IF ( PEEK (IS) AND 1) = 0 GOTO 181
195 R(C) =  PEEK (IN)
200 C = C + 1:ER = 0
210  GOTO 180
211  REM ------------------------
220  IF C = 1 THEN  PRINT "C004 FOUND"
230  IF C = 2 THEN  PRINT "16 BIT TRANSPUTER FOUND"
240  IF C = 4 THEN  PRINT "32 BIT TRANSPUTER FOUND"
250  IF C = 0 OR C > 4 THEN  PRINT "COULD NOT IDENTIFY""
1000  DATA 23,177,209,36,242,33,252,36,242,33,248
1001  DATA 240,96,92,42,42,42,74,255,33,47,255,2,0 

Ok, if this is running fine, i.e. a Transputer was actually found and your Apple didn’t went up in smoke, we’re set for some serious numbercruncing… and a video! Yay! We love Videos, don’t we?

(I’m skipping the other sample code available on the T2C64 page. It’ll work the same on an Apple, so no need for redundancy)

DIY Projects, DIY Transputer interfacing, T2A2

Mandelbrot and Video

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Like with the C64, this is probably the reason you came here:

The friggin’ fastest Mandelbrot displayed on a IIgs, ever! 😉

Yeah, you’re right, it’s not the fastest Mandelbrot calculated by an IIgs (its very own 65c816 CPU, that is)… but hey, it’s still kinda cool – and sooooo much faster!

Okey-Dokey, here we go, a complete Mandelbrot in 60s. This time in color… and zooming in! I couldn’t do that on the C64 as the C-Compiler didn’t natively support IEEE754 doubles (like Orca-C does) and having a mouse also helps a bit, too:

Wow, that was nice, wasn’t it?! (Sorry for the shaking, need to get a tripod soon)
Especially when you take in concern how ‘far’ the native 65c816 code got during the video on a ‘sped-up’ 10MHz TransWarp GS.

Like with the T2C64 version there are surely several things which could be improved, but the IIgs (even at native speed) is well capable to handle the little bit of extra work. The limiting factor is the bus-speed, i.e. how quick the Transputer can push his data into the host (IIgs). You can clearly see that by the time it took the display the 3 zooms: They all took about 60 seconds, even each zoom means more calculations as the iteration is doubled each zoom, in this case 32, 64, 128.
The Orca-C source/binary of this demo -and the previous AppleSoft sample- is available here (zip’ed PRODOS disk-image). It won’t make much sense without a T2A2 and is GS/OS-only as it uses QuickDraw II and the EventManager (for mouse & keyboard).

Final words: Don’t get too excited about the acceleration of the IIgs… it’s not accelerated at all. It’s more like a co-processor attached to it. And even then, you’ll need something really calculation-intensive to justify the time you’ll loose due to communication between the Apple and the Transputer. A single square-root for example wouldn’t make much sense.
But OTOH, that’s exactly things are handled with the Innovative Systems FPE (using a M68881). So it might be worth evaluating. Maybe I’ll write a SANE driver if I have the time to get a deeper understanding of GS/OS.

As my two targets (C64 & Apple II) are working now, I’m thinking about creating a ‘real PCB’ in the medium term. Given the rarity of the Link-Adaptor (Inmos C012) I’m currently looking into the possibility to use a larger CPLD to move the C012 into that. This would actually make this ‘project’ a product to buy.
But don’t hold your breath, need to get an eval kit first. Then some 100 days of fiddling, cursing and crying… and then more.

well, 6 years later it happened: The T2A2 became a proper PCB design… and got some additions too!

Apple II, DIY Projects, T2A2

T2A2 for everyone

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While the guys over at OpenApple were speculating in their latest podcast what a Transputer actually is… well, there are about a 100 links and ways on this page to find out – but hey… just click here – and of course that box saying search would do great wonders, too.

But seriously, my bad: I should have mentioned that this page your looking at is really just one post of many… so make sure you start at a Chapter (Menu. At the Top. ↑…yes up there) and read them in the order you’d read a book 😉

After quite some years (and a handful Apple II users requests) I felt the urge to finally put the T2A2 prototype (read that post to get a more general understanding) into a real expansion card… and here it is: Say “Hello!” to the T2A2 version 1.1!

It came a long way…

t2a2_evolution

…in more detail:

t2a2_front

As you can see, the final T2A2 is much smaller than the prototype (which used an 8bit Baby one-for-all PCB) and offers many additional features

  • 2 size-1 TRAM slots (or one size-2) – double the processing power!
  • Low-power, low-profile parts used where possible (3.3V CPLD, HCT logic)
  • External Transputer-link available as edge connector – extend your network to “near infinitum“
  • Jumpers for LinkSpeed and optional power to the Transputer-link connector
  • Fully buffered to be a good Apple II bus citizen
  • Works in any slot set to “your card”

Beyond this, everything said about the prototype is still true.

Most important:

a) It’s not tested in the ][ or ][+. I simply don’t own one of those.
Update: One owner reported it’s perfectly working in his IIe!
b) The T2A2 won’t instantly speed up any of your Apple II[e/gs] applications.

It’s more like a co-processor attached to it. And even then, you’ll need something really calculation-intensive to justify the time you’ll loose due to communication between the Apple and the Transputer. A single square-root for example wouldn’t make much sense – but having a complex algorithm (like the Mandelbrot fractal in my demo)  does absolutely make sense, as you just pass the parameters to the Transputer and let him do the sweating.

But on the other hand, FPU cards like the Innovative Systems FPE (using an M68881) or my even faster clone “NumberCruncher Reloaded” did just send instruction by instruction. So I somehow fancy the idea writing a SANE driver for GS/OS to integrate the T2A2 more transparently.

Want your own T2A2?

So now you’re keen to get one yourself? Please check this list first:

  • Do you have a TRAM already? (*)
  • You are aware that there’s no real software (yet) besides my little Mandelbrot demo?
  • You are keen to program something yourself – or are fine to wait until somebody else did?

While the Apple II side of coding is pretty easy, you have to get a grip about the Transputer development, too. That includes a DOS/Windows (<=XP) setup and some knowledge of C and/or OCCAM. I’ve created a little Transputer “SDK”, namely a VirtualBox image running DOS.

Plenty of Dev-Docs are available here.  
I suggest using the INMOS cross-compilers for C or OCCAM. An alternative C compiler came from LSC, which might suit you more if you don’t like the INMOS stuff.

Ok, so you’re still with me… so I have the first batch of 20 T2A2 PCBs ready which I will populate on-demand, and for 40€ (plus shipping) one of them can be yours.
(*) I might be able to offer you a TRAM, too. The price depends on available model, RAM size and CPU used.

⇒ drop me a mail tonobody likes SPAM
(Sorry, you have to type that into your mail-client – nobody likes SPAM, so do I)

Also check the T2A2 forum for current availability, shipping procedure and built status.

Some more technical details

Here’s a T2A2 with a size-1 TRAM installed in Slot-0:

t2a2_with_tram

The T2A2’s CPLD programming can be updated any time through a JTAG port (the lower 2×5 pin-row at the edge).
The jumper above it can be used to set the linkspeed for the TRAMs (10 or 20mbps). If you look very close, there’s a tiny LED next to that jumper. It’s the error LED controlled by the CPLD.
The next single jumper enables the VCC pins on the external Link connector, meant for (small!) external extensions. This connector is the same used on the Gerlach card and is very convenient because of its ubiquitous standard 2×5 shrouded pcb header connector. Here’s the pinout:

As said, the V1.1 T2A2 offers two size-1 TRAM slots. Before plugging in 40MIPS of raw processing power consider the amount of juice being pulled there. Depending on the amount of RAM and load a single TRAM can use up to 800mA of power!  😯
Given the max. of 4A on a standard IIgs power-supply, two TRAMs could bring your souped-up GS into trouble… it’s better to use the external connector with just one smaller TRAM or even simply bridge the Link0In/Out pins with Link3In/Out so that the T2A2 works as a TRAM-less adapter.
That said, there are size-2 TRAMs in existence which will snugly fit  and won’t hurt that much.