Service manual

Service Manual
Sockets (cont.)
Skt
Fitted
Function/Specification
SK11
Yes
6-way mini-DIN socket providing the
connection point for the keyboard. If required,
a standard Archimedes keyboard may be
plugged into this socket.
SK12
Yes
High resolution mono video output.
Provides a 0.7V mono video signal (into 75
Ohm) at a dot rate of 96MHz. This requires a
High resolution monitor to be connected.
SK13
Yes
High resolution mono vertical sync.
Provides composite/vertical synchronisation
pulses for the high resolution mono output.
SK14
Yes
High resolution mono horizontal sync.
Provides horizontal synchronisation pulses for
the high resolution mono output.
Internal expansion
Interface
Introduction
The computer supports an expansion card (podule)
interface. The maximum power available per slot can be
calculated from the following:
• The +5V supply rail is rated at a maximum of 1A
• The +12V supply rail is rated at a maximum of 250mA
• The -5V supply rail is rated at a maximum of 50mA
Refer to the application note 'A Series Podules' for a full
podule interface specification, available on request from
Acorn Computers.
Pin
a
c
Description
1
0V
0V
Ground
2
LA[15]
—5V
3
LA[14]
0V
Ground
4
LA[13]
0V
Ground
5
LA[12]
reserved
6
LA[11]
MS[0]*
MEMC Podule select
7
LA[10]
reserved
8
LA[9]
reserved
9
LA[8]
reserved
10
LA[7]
reserved
11
LA[6]
reserved
12
LA[5]
RST*
Reset (see note below)
13
LA[4]
PR/W*
Read/not write
14
LA[3]
PWE*
Write strobe
15
LA[2]
PRE*
Read strobe
16
BD[15]
PIRQ*
Normal interrupt
17
BD[14]
PFIQ*
Fast interrupt
18
BD[13]
S[6]*
19
BD[12]
C1
12C serial bus clock
20
BD[11]
C0
12C serial bus data
21
BD[10]
S[7]*
External Podule select
22
BD[9]
PS[0]*
Simple Podule select
23
BD[8]
IOGT*
MEMC Podule handshake
24
BD[7]
IORQ*
MEMC Podule request
25
BD[6]
BL*
I/O data latch control
26
BD[5]
0V
Supply
27
BD[4]
CLK2
2MHz Synchronous clock
28
BD[3]
CLK8
8MHz Synchronous clock
29
BD[2]
REF8M
8MHz Reference clock
30
BD[1]
+5V
Supply
31
BD[0]
reserved
32
+5V
+12V
Note: The RST* signal is the system reset signal, driven by
IOC on power up or by the keyboard reset switch. It is an
open-collector signal, and expansion cards may drive it also
if this is desirable. The pulse width should be at least 50ms.
Part 1 - System description Issue 2, June 1991 1-19