DS1481 Datasheet, PDF (1/10 Pages) Dallas Semiconductor – 1.Wire Bus Master with Overdrive

DS1481
PRELIMINARY
DS1481
1–Wire Bus Master with Overdrive
FEATURES
• Provides a synchronous interface to Dallas Semicon-
ductor 1–wire devices
• Compatible with low power parallel ports
• Can be cascaded with other DS1481’s
• Allows print spooler and other processes to run during
1–wire I/O
• Provides high speed communcation with overdrive
capable devices
• Space saving 14–pin (150 mil), SOIC package
DESCRIPTION
The DS1481 is a dedicated 1–wire timing generator.
The device is normally used in conjunction with a paral-
lel port controller to provide the necessary interface to
the host processor. Busy signals allow the host proces-
sor to perform other tasks while 1–wire “time–slots” are
completed. The DS1481 also saves the state of D/CLK
and RES allowing print spoolers to operate without
affecting 1–wire communication.
DS1481 based devices can be cascaded. The first
device’s O1/BSY1 and O2/BSY2 connect to the PC
PIN ASSIGNMENT
V_CC
1
ENI
2
O1/BSY1
3
O2/BSY2
4
D/CLK
5
RES
6
NC
7
14
I/O
13
ENO
12
I1
11
I2
10
NC
9
NC
8
GND
14–PIN SOIC (150 MIL)
PIN DESCRIPTION
V_CC
– Supply
ENI
– Enable In
D/CLK
– Data/Clock
RES
– Reset
O1/BSY1
– Output 1/Busy 1
O2/BSY2
– Output 2/Busy 2
GND
– Ground
I1
– Input 1
I2
– Input 2
I/O
– 1–wire I/O
ENO
– Enable Out
NC
– No Connect
printer port’s BUSY and SELECT OUT signals (pins 11
and 13 respectively). The next DS1481 connects its
O1/BSY1 and O2/BSY2 to the first device’s I1 and I2
respectively. ENO of the first device connects to ENI of
the second device. More DS1481’s can be stacked in a
similar manner. The last devices I1 and I2 connect to
BUSY and SELECT of the attached printer.
The DS1481’s 3–volt operation insures compatibility
with most low power parallel ports (i.e., portable com-
puters).
021798 1/10