dallas semiconductor DS2109DK, DS2109 service manual
查询DS2109DK供应商
DS2109DK
DS2109DK
DS2109 Demo Board
The DS2109DK is used in Plug and Play SCSI motherboards and host bus adapters to provide automatic
active termination for 18 pairs of signal lines and is available in a 28–pin SOIC package. The DS2109DK is a
demo board for both narrow and wide SCSI. A
DS21S07AE is used with the DS2109DK to terminate
27 lines for a SCSI–2 or SCSI–3 wide bus.
To use as a terminator for a narrow bus, connect the
SCSI cable into J2 of the DS2109DK. T o use at the end
of a wide bus, connect to J1. T est points are available for
all of the SCSI bus signals. The TERM PWR LED indicates termination power from the bus.
To demonstrate the automatic termination schemes of
the DS2109DK, connect cables to both J1 and J2. The
SCSI specifications require terminators installed in the
middle of the SCSI bus to be powered down or isolated
from the bus. The PDO LED will turn on when the
DS2109DK is isolated from the SCSI bus. The ground
detect method is controlled by switch GND DETECT.
Move the switch to YES, and if SCSI devices are
installed at both connectors, the PDO LED will come on.
The current sense method requires switch CURRENT
SENSE to be YES and then swtiching the RESET
switch from FLOAT to GND to FLOAT. This imitates a
SCSI reset from the host controller. If terminators are
connected to J1 and J2, the PDO LED will light. When
not demonstrating the automatic termination schemes,
leave switches S1 and S2 at NO and switch S3 at
FLOAT.
MATERIALS USED:
PART DESCRIPTION SOURCE PART NUMBER
U1 Plug and Play SCSI Terminator Dallas Semiconductor DS2109S
U2 SCSI Active Terminator Dallas Semiconductor DS21S07AE
J1 Wide SCSI connector Thomas and Betts HFR068RA29BS1
J2 Narrow SCSI connector Thomas and Betts 501–5007ES
S1–3 Switch PM Circuits Inc. D7789
C1 2.2 µF/16V tantalum capacitor Sprague 293–X225X9010A2T
C2, C4 4.7 µF/10V tantalum capacitor Kemet T491A475K010AS
C3, C5 0.1 µF/10V ceramic capacitor Kemet C1206C103K5RAC
L1–2 SMT Red LED Jlead Digikey P500
Z1 350 mW SOT23 2.7V Zener Digikey BZX84C2V7ZX
R1–2 1/8W 5% 1.2K Resistor MEPCO 9C12063A1201JKR
022698 1/3
DS2109DK
DS2109DK LAYOUT
YES
NO
DETECT
J1
GND
YES
S1
NO
CURRENT
SENSE
DB0
DB1
DB2
DB3
DB4
DB5
DB6
DB7
DB8
DB9
DB10
DB11
DB12
GND
S2
FLOAT
RESET
U1
DS2109S
C2
C3
C1
U2
DS2109S
C4
PDO LOW
L1 Z1
S3
R1 R2
I/O
REQ
C/D
SEL
MSG
RST
ACK
BSY
ATN
DBP
TP
GND
DBP1
DB15
DB14
DB13
TERM PWR
L2
J2
022698 2/3
C5
DS2109DK DEMO
DALLAS SEMICONDUCTOR
CALL 214–450–8110 FOR INFO
Loading...