my hobbies
Altair 680bI built this computer from a kit which my late brother purchased when it was first released in 1976. I can still remember having to solder all the LEDs and toggle switches by hand --uugghh-- it's ingrained into my subconscious. I still have all my original documentation which came inside the kit. It contains all the manuals (Programmers, Users, Assembly, etc, etc) with my notes from back then when we built this machine.
I/O configuration:
Here are some scanned pages from the Assembly manual and Schematics
pg.16, IC L, 74LS74 --needed for baudot terminal only [pdf]
pg.29, assy instructions, [pdf]
pg.30, assy instructions, [pdf]
Schematics, IC L, Baudot only, sht.2, rt half, [pdf]
pg.16, IC L, 74LS74 --needed for baudot terminal only [pdf]
pg.29, assy instructions, [pdf]
pg.30, assy instructions, [pdf]
Schematics, IC L, Baudot only, sht.2, rt half, [pdf]
Reset circuit:
Silkscreen error on motherboard rev 1-6X, photo [jpg]
The photo shows Q2,Q3 (both 2N4410) mounted in reverse position. This is because the Silkscreen incorrectly identifies the position that the Emitter leg of the transistor should be placed.
![[jpg]](files/altair/reset_circuit-sm.JPG){kind=link}
The photo shows Q2,Q3 (both 2N4410) mounted in reverse position. This is because the Silkscreen incorrectly identifies the position that the Emitter leg of the transistor should be placed.
The
silkscreen shows where the Emitter leg of the transistors would be
inserted by the 'E' symbol located on the silkscreen. However, the
silkscreen is incorrect and doesn't match the schematic. The
Collector leg of the transistors (both Q2 and Q3) should be inserted in
this hole (as shown in the picture) instead in order to correctly wire
the circuit as shown in the schematic.
Altair 680 BASIC
This listing is a text file converted from the original papertape.
MITS Altair 680 Basic v1.1 KCACR Cassette [txt]
MITS Altair 680 Basic v1.1 Papertape [txt]
Instructions:
1. Bootup the machine with the ACIA monitor rom
(provided you tested this already).
2. Type "L" at the monitor prompt
This is how you normally load from paper tape.
3. Select "Send a Text file" from the transfer menu
MITS Altair 680 Basic v1.1 KCACR Cassette [txt]
MITS Altair 680 Basic v1.1 Papertape [txt]
Instructions:
1. Bootup the machine with the ACIA monitor rom
(provided you tested this already).
2. Type "L" at the monitor prompt
This is how you normally load from paper tape.
3. Select "Send a Text file" from the transfer menu
(no character or line delays are needed)
4. Select a paper tape image (text file)
KCACR BASIC (Cassette BASIC) appears to be the regular basic with only
patches for the CSAVE and CLOAD commands. The reasoning behind this is if your
program needs the 340 bytes in memory.
Both files take about 20 seconds to load into an Altair 680 at 9600bps
patches for the CSAVE and CLOAD commands. The reasoning behind this is if your
program needs the 340 bytes in memory.
Both files take about 20 seconds to load into an Altair 680 at 9600bps
.J 0000
MEMORY SIZE? <cr>
TERMINAL WIDTH? 80
WANT SIN-COS-TAN-ATN? YES
9604 BYTES FREE
MITS ALTAIR 680 BASIC VERSION 1.1 REV 3.2
--KCACR--
COPYRIGHT 1976 BY MITS INC.
MEMORY SIZE? <cr>
TERMINAL WIDTH? 80
WANT SIN-COS-TAN-ATN? YES
9604 BYTES FREE
MITS ALTAIR 680 BASIC VERSION 1.1 REV 3.2
--KCACR--
COPYRIGHT 1976 BY MITS INC.
COMPARED TO:
.J 0000
MEMORY SIZE? <cr>
TERMINAL WIDTH? 80
WANT SIN-COS-TAN-ATN? YES
9946 BYTES FREE
MITS ALTAIR 680 BASIC VERSION 1.1 REV 3.2
COPYRIGHT 1976 BY MITS INC.
MEMORY SIZE? <cr>
TERMINAL WIDTH? 80
WANT SIN-COS-TAN-
9946 BYTES FREE
MITS ALTAIR 680 BASIC VERSION 1.1 REV 3.2
COPYRIGHT 1976 BY MITS INC.