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AT INTERFACE DESCRIPTION
5 – 2
Pin Description Table
Pin Description Table
Pin Description Table
Pin Description Table
Pin Description Table
PIN NAME
PIN
I/O
SIGNAL NAME
SIGNAL DESC RIPTION
RESET -
01
I
Hos t Reset
Reset si gnal from the host s ystem. Acti ve during power up and inacti ve afte
D D0
17
I/O
Host Data Bus
16 bit bi-directional data bus between host and dri ve. Lower 8 bi ts used for
register and EC C byte transfers. All 16 bi ts us ed for data transfers.
D D1
15
I/O
D D2
13
I/O
D D3
11
I/O
D D4
09
I/O
D D5
07
I/O
D D6
05
I/O
D D7
03
I/O
D D8
04
I/O
D D9
06
I/O
DD 10
08
I/O
D D11
10
I/O
DD 12
12
I/O
DD 13
14
I/O
DD 14
16
I/O
DD 15
18
I/O
D MARQ21
O
DM A Request
This signal is used wi th DM AC K for D MA transfers . By asser ti ng thi s s ignal
dri ve indi cates that data is ready to be transfered to and from the host.
DIOW -
STOP
23
I
Host I/O Write
Risi ng edge of Wr ite strobe clock s data from the hos t data bus to a regi ster
the drive.
D IOR -
HD MARDY
-
HSTROBE
25
I
Host I/O Read
Read strobe enabl es data from a register on the dri ve onto the host data b u
DMA ready duri ng UltraDMA data in bursts.
Data strobe during UltraDMA data out bursts.
IORDY
DD MARDY
-
DSTROBE
27
O
I/O C hannel Ready
This signal may be driven low by the dri ve to insert wait states into host I/O
cycles.
D MA ready duri ng UltraDMA data out bursts.
D ata str obe during Ul traDMA data in bursts.
CSEL
28
C able Select
Us ed for Mas ter/Slave selection via cabl e. Requires s peci al cabling on host
s ystem and i nstallation of C abl e Sel ect jumper.
D MACK -
29
I
D MA Acknowledge
This signal is used wi th DM ARQ for D MA transfers . By asser ti ng thi s s ignal
host is ac knowledging the recei pt of data or i s indicating that data is availa
INTRQ31
O
Hos t Interrupt
Request
Interrupt to the host asserted when the dri ve requi res attenti on from the host
IOC S16
32
D evi ce 16 bit I/O
Obsolete
PD IAG -
34
I/O
Pas sed D i agnostic
Output by dri ve when in Slave mode; Input to drive when in Master mode.
DA0
35
I
Hos t Address Bus
3 bi t binary address from the host to selec t a regis ter in the dri ve.
DA1
33
I
DA2
36
I
C S0 -
37
I
Host Chip Select 0
C hi p sel ec t from the host used to access the C omm and Bl ock registers in th
dri ve. Thi s si gnal i s a decode of I/O addres ses 1F0 - 1F 7 hex.
C S1 -
38
I
Host Chip Select 1
Chip select from the host used to access the Control registers in the drive. T
si gnal is a decode of I/O addres ses 3F6 - 3F 7 hex.
DASP -
39
I/O
Drive Active/D ri ve
1 Present
Ti me-multiplexed, open collector output whi ch i ndi cates that a drive i s active
that
device 1 is pres ent.
GND
02
N/A
Ground
Si gnal ground.