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A1200PT2.TXT
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1993-02-10
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133 lines
The Amiga A1200: Inside & Out
Part 2 Feb 10th 1993
(C)1993 Silicon Synapse Electronics & John Kamchen
SSE BBS (204)589-1078 MEGS of AmiTronics hacks.
The information contained in this document should not be considered to be 100%
accurate, as I am having a hard time finding anything official on this system.
---------
After doing alot of phone calling, I was able to obtain the pinouts for
both IDE drive formats (the 2.5" & 3.5"). These come from Maxtor, and are
valid for both the A600 and A1200 (tho there is some debate as to whether the
Maxtor 2.5" drives work reliably on the A1200). The pinouts are standard for
any IDE drive, so the source doesn't matter much.
The pinouts are as follows: (_NAME means signal active low)
Name 2.5" 3.5" Desc
_RESET | 1 | 1 | Drive reset
GROUND | 2 | 2 |
DD7 | 3 | 3 | Drive data bus bit 7
DD8 | 4 | 4 | Drive data bus bit 8
DD6 | 5 | 5 | Drive data bus bit 6
DD9 | 6 | 6 | Drive data bus bit 9
DD5 | 7 | 7 | Drive data bus bit 5
DD10 | 8 | 8 | Drive data bus bit 10
DD4 | 9 | 9 | Drive data bus bit 4
DD11 | 10 | 10 | Drive data bus bit 11
DD3 | 11 | 11 | Drive data bus bit 3
DD12 | 12 | 12 | Drive data bus bit 12
DD2 | 13 | 13 | Drive data bus bit 2
DD13 | 14 | 14 | Drive data bus bit 13
DD1 | 15 | 15 | Drive data bus bit 1
DD14 | 16 | 16 | Drive data bus bit 14
DD0 | 17 | 17 | Drive data bus bit 0
DD15 | 18 | 18 | Drive data bus bit 15
GROUND | 19 | 19 |
key | 20 | 20 | Key for interface connector
DMARQ | 21 | 21 | DMA request (not supported yet)
GROUND | 22 | 22 |
_DIOW | 23 | 23 | Drive I/O write
GROUND | 24 | 24 |
_DIOR | 25 | 25 | Drive I/O read
GROUND | 26 | 26 |
IORDY | 27 | 27 | I/O channel ready
SPSYNC | 28 | 28 | Spindle sync (not supported yet)
_DMACK | 29 | 29 | DMA acknowledge (not supported yet)
GROUND | 30 | 30 |
INTRQ | 31 | 31 | Drive interrupt
_IOCS16 | 32 | 32 | Drive 16 bit I/O
DA1 | 33 | 33 | Drive address bus bit 1
_PDIAG | 34 | 34 | Passed diagnostics
DA0 | 35 | 35 | Drive address bus bit 0
DA2 | 36 | 36 | Drive address bus bit 2
_CS1FX | 37 | 37 | Chip select 0
_CS3FX | 38 | 38 | Chip select 1
_DASP | 39 | 39 | Drive active/slave present
GROUND | 40 | 40 |
+5v | 41 | -- | +5v supply
+5v | 42 | -- | +5v supply
GROUND | 43 | -- |
RESERVED| 44 | -- | Reserved for future definition
As you can see, apart from the power pins, all the signals are exactly the
same. The ones that say 'not supported yet' should still be connected.
The 44pin connector isn't a normal .1" IDC header, it's more like .075".
I'm still trying to track down the source of these connectors/cables. The
local computer store should have some of these around, and I'll have to do 40
solder joints to join it to a normal IDE plug. If I come up with a better
way, I'll let you guys know.
If you are like me, you will want to use a 3.5" hard drive on this system,
because of the cost of those stupid 2.5" units (they run about $150 more than
the equivalant sized 3.5" drive). Aside from the cost factor, there is a
storage consideration. The largest 2.5" I've heard of is 120mb, but there
might be a 240mb lurking around somewhere. Myself, I wouldn't put anything
less that 240mb in this computer.
* NOTE *
The 3.5" drive you use must be an 'LPS' type (LOW PROFILE!).. 1 inch high
-| There may be a conflict with your warranty sticker & a screwdriver |-
When I bought my sysytem, the computer has something rattling around inside
and the power LED didn't work.. plus something was wrong with the workbench
screen. These were all valid warranty complaints, and I didn't do anything
dishonest. The tech checked over the system (the mystery object fell out,
the power LED worked, but the WB screen was still odd). I felt stupid, but
went in with good intentions (the car always starts as the tow-truck
arrives). Lucky me, they didn't put another sticker over a screw. You too
may be just as lucky. But, if you take in your system with a 'phantom
problem', you have to live with the results (such as paying the shop fee for
wasting their time). As well, if you damage the computer (like cutting
wires, bending metal, blowing the IDE chip) the warranty is for sure gone no
matter what you offer as an excuse.
Ever wonder why the drive is put in at an angle? It's not meant to look
pretty (tho it does). The reason is simple: SPACE! The inside on the A1200
is really cramped, what with all the metal shielding and all. In a 500, many
people bolted the drive to the underside of the top case (under the vent
holes) and it proved to work very well. The A1200 doesn't have that option.
Space is at a premium.
* DO NOT DAMAGE OR DISASSEMBLE ANY ORIGINAL CABLES OR CUT ANY METAL *
* You should be able to restore the A1200 to as-new condition should *
* it require warranty work in that vital first year *
1) Remove the floppy drive, make it external. This is as easy as it sounds.
The floppy cable (34 conductor) can be extended by any means you see fit.
Simplest way would be to buy a drive cable from the local computer store.
The power connector for the floppy will be shared with the HD, so look at
your needs, and come up with something. The HD is bound to have the
normal 4 pin power plug. There will be some soldering done here, keep it
neat. To shield the floppy cable, wrap it in aluminium foil & duct tape
(run the power plug inside the shielding!). A case from Active or Radio
shack can house DF0: (make it look nice, eh?). This is better than using
a 'shuffle board' system, because it allows to keep the external drive
port free for DF1-3:.
Install the 3.5" HD in the floppy bay. Don't loose that angle bracket.
The drive should sit really nice, and not be wedged against anything.
One thing you have to look out for is that the drive connectors (40 pin &
power) don't get wedged against the sheilding. You might need to bend the
metal a wee bit, but I hope not.
Doing it this way has two benefits: Simple to do (as easy as it gets) and
should you need to take the machine into the shop for repairs, you can
dismantle everything, put the floppy drive back in place, and close it up!
You still need to get ahold of the Commodre Install disk to use the HD.