27 Jul
2004
27 Jul
'04
3:12 a.m.
Anyone happen to have a copy of the Intel D82284 IC (18 pin DIL)
datasheet? I think it's some form of clock generator IC; I have an 80286
board which uses one that I'm trying to fix and just want to verify that
the system's clocking OK.
cheers,
Jules
10:13 a.m.
Anyone happen to have a copy of the Intel D82284 IC (18 pin DIL)
datasheet? I think it's some form of clock generator IC; I have an 80286
I have the 82C284 data sheet, which is the CMOS version. I assume it's
very similar.. It's described as 'Clock Generator and Ready Interface for
80286 Porcessors', and I remmeebr it being used in the IBM PC/AT.
Anyway, here's a pinout :
1 : ARDY/ (Asynchronous Ready Input)
2 : SRDY/ (Synchronous Ready Input)
3 : SRDYEN/ (SRDY Enable Input)
4 : READY (Ready output to CPU)
5 : EFI (External Frequneny Input, TTL clock in)
6 : F, C/ (Clock Select Input. High = use EFI, Low = use Xtal)
7 : X1 (Xtal connection)
8 : X2 (Ditto)
9 : Gnd
10 : Clk (Processor Clock output)
11 : RES/ (Reset Input)
12 : Reset (Synchronised Reset output to CPU)
13 : PCLK (Peripheral Clock Output)
14 : N/C
15 : S0/ (Status Input from CPU)
16 : S1/ (Ditto)
17 : ARDYEN/ (ARDY Enable Input)
18 : Vcc
board which uses one that I'm trying to fix and
just want to verify that
the system's clocking OK.
Check for a clock signal at twice the 'specified' CPU clock (e.g. 16MHz
for an 8MHz machine) at pin 10.
Most 286 machines were pretty close to the IBM PC/AT schematic. Do you
have access to the TechRef?
-tony
10:44 p.m.
On Tue, 2004-07-27 at 22:13, Tony Duell wrote:
Yep, I actually stumbled across the same IC by accident and did find the
datasheet for that one; I'm also assuming that they're compatible. The
datasheet does say that the chip's designed for the 80C286, but I'm
presuming they're interchangeable (particularly for my purposes at
present of just making sure it's doing *something*)
Anyone happen to have a copy of the Intel D82284 IC (18 pin DIL)
datasheet? I think it's some form of clock generator IC; I have an 80286
I have the 82C284 data sheet, which is the CMOS version. I assume it's
very similar.. It's described as 'Clock Generator and Ready Interface for
80286 Porcessors', and I remmeebr it being used in the IBM PC/AT. Most 286 machines were pretty close to the IBM PC/AT
schematic. Do you
have access to the TechRef?
Hmm, we'll have one at Bletchley. This is actually for the 286
coprocessor board in my newly-aquired Acorn ABC 310, but the techref
should still contain a lot of relevant stuff.
Service manuals for the machine do survive *somewhere* in the original
owner's attic, so I can get my paws on them later this year when he
finds them; but as the chap whose hands this machine just passed through
saw it boot once I'm hopeful I can sort it out before then.
I'm yet to hear an estimate of the number of such boards made - they
were never sold commercially by Acorn, but apparently did get used
in-house for a lot of the development work on the Master 512 copro
(indeed, mine has Master 512 ROMs fitted). Presumably cost kept Acorn
from just using the 286 as the coprocessor in the
Master 512.
The board I have is an issue D, but I'm not aware of any other
survivors, other than in the original owner's '310 (yes, he had two, and
the empty shell of a third). Presumably issues A-C existed only on
paper, breadboards in the lab etc.
cheers,
Jules
28 Jul
28 Jul
11:19 a.m.
I have the 82C284 data sheet, which is the CMOS version. I assume it's
very similar.. It's described as 'Clock Generator and Ready Interface for
80286 Porcessors', and I remmeebr it being used in the IBM PC/AT.
Yep, I actually stumbled across the same IC by accident and did find the
datasheet for that one; I'm also assuming that they're compatible. The
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