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.