This example actually puts the Transputer to some sort of use… well, it’s still way beneath him but it does its job as an example.
Two tasks: a) Read the Transputer executable from disk and b) exchange data with the Transputer.

Here we go:

10 PRINT"INIT TRANSPUTER"
20 POKE 56840,0
30 POKE 56844,0
40 POKE 56840,1:POKE 56840,0
50 FOR W=0 TO 1000:NEXT W
60 POKE 56834,0
70 POKE 56835,0
80 REM READ STATI
90 PRINT "I STATUS: ";(PEEK(56834)AND1)
100 PRINT"O STATUS: ";(PEEK(56835)AND1)
110 PRINT"ERROR: ";(PEEK(56840)AND1)
140 PRINT"O STATUS: ";(PEEK(56835)AND1)

Up to here everything should be clear. Init Transputer, read stati -just to be sure.
Now we’re reading the executable (“GRAB”) from floppy and poke the bytes to the Transputer as they come flying crawling in:

150 DIM R(4)
160 PRINT"SENDING PROGRAM TO TRANSPUTER..."
170 REM READ TRANSPUTER BIN FILE
180 OPEN 1,8,2,"0:GRAB,S,R"
190 FOR I=0 TO 1 STEP 0
200 IF ST=64 GOTO 240
210 GET#1,A$:A=ASC(A$+CHR$(0))
220 POKE 56833,A
230 NEXT I
240 CLOSE 1

Ok, the Transputer binary expects us to tell it the number of integers we’re about to send to it (AN), the we send these (X) and finally re-read the results… which should all be X+7.

250 INPUT"COUNT:";AN
255 POKE 56833,AN
260 FOR AA=1 TO AN
270 PRINT"ENTER ";AA:INPUT X
280 POKE56833,X
290 NEXT AA
295 PRINT"GETTING";PEEK(56832);" RESULTS"
300 FOR BB=1 TO AN
310 PRINTPEEK(56832);
320 NEXT BB

Some final words about Transputer executables. There are many kinds depending which development system was used. Some need special loaders or bootfiles before the actual binary will be send to the Transputer. A ‘raw’ upload is only possible with binaries mostly having the extension of “.btl” (BooTfromLink). AFAIK only the OCCAM SDK and the Inmos C-compiler ‘icc’ will create those executables.

For those geeks who actually (still) do know their OCCAM, here’s the source of GRAB:

PROC first(CHAN OF BYTE in, out)
  #USE "hostio.lib"

  BYTE data.in, data.out :
  INT count, temp :
  [1000]BYTE array :

-- {{{ start main SEQ

  SEQ
    in ? data.in
    count := (INT data.in)
    SEQ i=0 FOR count
      in ? array[i]                   

        -- {{{ inner loop
        
            SEQ i=0 FOR count
              SEQ
                temp := (INT array[i])
                temp := temp + 7
                array[i] := (BYTE temp)
        
        -- end of inner loop
        -- }}}
                
    out ! (BYTE count)
    SEQ i=0 FOR count
      out ! array[i]          
    in ? data.in       -- debug only
    CAUSEERROR()

-- }}}
        
:

For the fun of it, here’s my first Commodore BASIC v2 program which does 3 things.

1. Line 1-50: Initialize the Transputer and set/get its status.
2. Line 69-110: Write (poke) some data into T’s memory and read (peek) it back.
3. Line 128-240: Send a little program to the T and read its result.

10 PRINT"INIT TRANSPUTER"
11 POKE 56840,1:POKE 56844,0:POKE 56840,0
20 REM CLEAR I/O ENABLE
21 POKE 56834,0: POKE 56835,0
30 REM READ STATI
31 PRINT "I STATUS: ";(PEEK(56834)AND1)
35 PRINT"O STATUS: ";(PEEK(56835)AND1)
40 PRINT"ERROR: ";(PEEK(56840)AND1)

This is the Transputer POKE command (0) which tells the T that the next 4 bytes are an address followed by 4 bytes of data:

45 PRINT"SENDING POKE COMMAND"
46 POKE 56833,0
50 PRINT"O STATUS: ";(PEEK(56835)AND1)
58 :

Mind that were little endian and BASIC is using decimal numbers. So we’re POKEing 0,0,0,128 which is 0x00, 0x00, 0x00, 0x80 in hex which again is the 32bit address of 0x80000000.

59 PRINT"SENDING DATA TO T."
60 POKE56833,0:POKE56833,0:POKE56833,0:POKE56833,128
61 POKE56833,12:POKE56833,34:POKE56833,56:POKE56833,78
70 PRINT"I STATUS: ";(PEEK(56834)AND1)
79 :

Now reading back (PEEK) from 0x80000000 what we just wrote:

80 PRINT"READING FROM T."
90 POKE56833,1:REM PEEKING
100 POKE56833,0:POKE56833,0:POKE56833,0:POKE56833,128
110 PRINTPEEK(56832);PEEK(56832);PEEK(56832);PEEK(56832)

These 4 sequential PEEKs print 12 34 56 78. Yay! A very simple Ram-disk if you want.

Now something more serious. A very small programm is sent to the T and executed. Instead of peek and poke (1/0) the initial ‘command’ is the length of the program (23 in this case), so the T starts executing after he received the 23rd byte.
The program itself is trivial, after some initialisation it writes 0xAAAA0000 to link0out. The use of it is very simple. If the Transputer is working correctly the first 2 bytes will allways be “0xAA”, if it is just a 16bit Transputer (T2xx) there won’t be more than 0xAAAA. A 32bit Transputer returns the full 0xAAAA0000. Voilá, that’s a simple T-detection.
To handle timeouts end error conditions I had to do some ugly things in BASIC. Sorry, don’t blame me, BASIC v2 is just… very basic.

120:
128 DIM R(4)
129 PRINT"SENDING PROGRAM TO TRANSPUTER..."
130 FOR X=1 TO 24
140 READ T:POKE56833,T
150 WAIT 56835,1
160 NEXT X
170 PRINT:PRINT"READING RESULT:"
175 C=0
180 N=TI+50
181 IF C=10GOTO 220
189 IF TI>N THEN ER=ER+1:IF ER=10 GOTO 220
190 IF (PEEK(56834)AND1)=0 GOTO 189
195 R(C)=PEEK(56832)
200 C=C+1
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"
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

Next up a bit more useful example, reading the Transputer executable directly from a binary file instead of having it in-line.