Transcript Introduction to Programming

Expanding the BASIC Stamp:
Useful peripherals
Programming Unit, Lecture 6
LSU 06/04/2007
Expanding the BASIC Stamp
1
BalloonSat Expansion
•The BalloonSat development board has basic features built-in but your
application may require additional devices or circuitry or connection to
external instruments.
•The BalloonSat prototype area can accommodate temporary
construction for experimentation and test. The prototype area may be
large for payload specific circuitry and devices.
•The P2 expansion connector allows easy access to the BASIC Stamp
I/O pins, power and GND for external expansion.
LSU 06/04/2007
Expanding the BASIC Stamp
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Memory expansion with EEPROM
•BalloonSat has one EEPROM
chip installed.
•Additional I2C EEPROMs can
share the I2C bus (SCL and
SDA).
•Address bits (Addr2-Addr0)
must be unique for each
EEPROM added to avoid bus
conflict.
LSU 06/04/2007
Expanding the BASIC Stamp
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Analog-to-Digital Converter
•BalloonSat has an existing
ADC.
•More ADC chips can be added
to prototype area or on external
circuitry.
•Devices may share SCLK and
DO if each device has dedicated
Chip Select (CS). Only one CS is
enabled at a time.
LSU 06/04/2007
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Digital-to-Analog Converter
•DAC7574 is one
example of an I2C
compatible DAC.
•DAC7574 is a 4channel DAC with an
analog output range of 0
to 5 volts.
LSU 06/04/2007
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Digital-to-Analog Converter
DAC with output buffer for high-voltage and high-current load.
•TBD
LSU 06/04/2007
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Digital I/O Pin Expansion
•The PCF8574 I/O
Expander features 8
additional I/O bits.
•Expansion bits can
be used as Inputs or
Outputs.
LSU 06/04/2007
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Serial Communication Expansion
•Some applications may require a dedicated asynchronous
communications port. Payloads needing radio telemetry or
connection to a GPS can use an added UART or USART
such as the Maxim3100.
LSU 06/04/2007
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BalloonSat Expansion Precautions
•The BalloonSat development board can be damaged by high
voltages or reverse polarity. Make sure that any connections
to the board do not expose BalloonSat to negative voltage
levels or voltages greater than 5 volts.
•Use caution when soldering in the prototype area. Do not
accidentally short VCC to GND.
•Turn the power off when making adding or removing
components or wiring in the prototype area.
LSU 06/04/2007
Expanding the BASIC Stamp
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