Phoenix International VL1-250-SC-DS, Техническая информация

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Scope
This chapter describes the overall features and specifications of the VL1-250-SC-DS .
Features
The VL1-250-SC-DS incorporates one or two very compact winchester disk drives within a single module. The hard
disk drive(s) is a high-performance winchester type with embedded disk drive control electronics. This microprocessor
controlled embedded controller is on the hard disk and is compatible with ANSI X3.131-1986 SCSI commands. The
hard drive is a very high performer, with a 1-to-1 interleave and an average track-to-track access times of 10 millisec-
onds or less. It incorporates an embedded at least 8 megabytes of cache buffer which is operated in “look ahead”
mode, providing buffering for sequential sector operations. The hard drive(s) has been carefully packaged with suitable
control cables and power distribution connectors for direct attachment to single board computers in the VME chassis or
to external devices.
Ultra 320 SCSI Interface Description
In order to provide a method of embedding the disk drive control electronics within the hard disk drive, several disk
drive manufacturers jointly defined an interface specification. This specification for the Small Computer System Inter-
face has become known throughout the industry as “SCSI”. Basically, the SCSI interface consists of the required
address, data and control signals from a wide SCSI Host Adapter. Since a goal of the specification is to allow the disk
drive to be connected via standard cable, the specification required buffering of all signals so that the drive could be
mounted a suitable distance from the board interface. This distance, however, is limited to twelve meters. The specifi-
cation provides all signals via a 68-pin header connector for use with standard 68 conductor ribbon cable and connec-
tors. Table 2-2 is a description of the Ultra320 SCSI pin definitions. The direction indicated is relative to the host.
Pin Signal Pin Signal Direction Description
1 +DB(12) 35 -DB (12) In/Out Bidirectional data line 12
2 +DB(13) 36 -DB (13) In/Out Bidirectional data line 13
3 +DB(14) 37 -DB (14) In/Out Bidirectional data line 14
4 +DB(15) 38 -DB (15) In/Out Bidirectional data line 15
5 +DB(P1) 39 -DB (P1) In/Out Bidirectional data line parity1
6 +DB(0) 40 -DB (0) In/Out Bidirectional data line 0
7 +DB(1) 41 -DB (1) In/Out Bidirectional data line 1
8 +DB(2) 42 -DB (2) In/Out Bidirectional data line 2
9 +DB(3) 43 -DB (3) I n/Out Bidirectional data line 3
10 +DB(4) 44 -DB (4) In/Out Bidirectional data line 4
11 +DB(5) 45 -DB (5) In/Out Bidirectional data line 5
12 +DB(6) 46 -DB (6) In/Out Bidirectional data line 6
13 +DB(7) 47 -DB (7) In/Out Bidirectional data line 7
14 +DB(P) 48 -DB (P) I n/Out Bidirectional data line parity
15 GND 49 GND - Ground reference
16 DIFFSENS 50 GND - SCSI Sense/Ground reference
17 TERMPWR 51 TERMPWR - Terminator Power
18 TERMPWR 52 TERMPWR - Terminator Power
19 RESERVED 53 RESERVED - Reserved for future use
20 GND 54 GND - Ground reference
21 +ATN 55 -ATN In/Out Attention
22 GND 56 GND - Ground reference
23 +BSY 57 -BSY In/Out Busy
24 +ACK 58 -ACK - In Acknowledge
25 +RST 59 -RST In Reset
26 +MSG 60 -MSG Out Message
27 +SEL 61 -SEL In/Out Select
28 +C/D 62 -C/D Out Control/Data
29 +REQ 63 -REQ Out Request
30 +I/O 64 -I/O Out Input/Output
31 +DB(8) 65 -DB (8) In/Out Bidirectional data line 8
32 +DB(9) 66 -DB (9) In/Out Bidirectional data line 9
33 +DB(10) 67 -DB (10 ) In/Out Bidirectional data line 10
34 +DB(11) 68 -DB (11) In/Out Bidirectional data line 11
Table 2-2: SCSI Pin Definition
NOTES:
(1)
The minus sign next to the signals indicates active low.
Features and Specifications 2-3