DS1050
OPERATION
Interface protocol is simplified to an 8-bit control byte and 8-bit data byte. Information can be read or
written to the DS1050 including a commanded shutdown operation.
Power-Up Configuration
The DS1050 powers-up to half-scale (10000B) providing 50% duty-cycle. In this mode, the DS1050 can
be used as a standalone oscillator of the frequency specified. Once powered, the PWM output can be
changed via the 2-wire addressable serial port.
Pin Description
V
cc
– Power supply terminal. The DS1050 will support operation from power supply voltages ranging
from +2.7 volts to +5.5 volts.
GND
– Ground terminal.
PWM
O
– Pulse-width modulated output. This output is a square-wave having amplitudes from 0 volts to
V
CC
. The duty cycle of this output is governed by a 5-bit control register. Output duty cycles range from
0% to 96.88%. An additional command sequence will provide a 100% duty cycle or “full-on.”
SCL
– Serial clock input.
SDA
– Serial bi-directional data I/O.
A0, A1, A2
– Device address (chip selects).
2-Wire Addressable Serial Port Control
The 2-wire serial port interface supports a bi-directional data transmission protocol with device
addressing. A device that sends data on the bus is defined as a transmitter, and a device receiving data as
a receiver. The device that controls the message is called a “master.” The devices that are controlled by
the master are “slaves.” The bus must be controlled by a master device that generates the serial clock
(SCL), controls the bus access, and generates the START and STOP conditions. The DS1050 operates as
a slave on the 2-wire bus. Connections to the bus are made via the open-drain I/O lines SDA and SCL.
The following I/O terminals control the 2-wire serial port: SDA, SCL, A0, A1, and A2. A 2-wire serial
port overview and timing diagrams for the 2-wire serial port can be found in Figures 2 and 5,
respectively. Timing information for the 2-wire serial port is provided in the “AC Electrical
Characteristics” table for 2-wire serial communications.
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DALLAS [ DALLAS SEMICONDUCTOR ]
