27 Jul
2004
27 Jul
'04
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