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Altimeter Module MS5607 (#29124)
The Altimeter Module is a high-resolution (20 cm) altimeter sensor, with SPI and I
2
C bus interface. The
module includes a pressure sensor and a temperature output, allowing implementation of an
altimeter/thermometer/barometer without any additional sensors. It provides a precise digital 24-bit
pressure and temperature value.
Features
High resolution: 20 cm
Thermometer range: -40 to +85 °C, with
<.01 °C resolution
Pressure range: 10 to 1200 mbar
Supports I²C and SPI communications
24-bit pressure and temperature values
Key Specifications
Power requirements: 3.3 to 6.5 VDC
Communication interface: I²C (up to 400 kHz) or
SPI (20 MHz)
Operating temperature: -40 to +185 °F (-40 to +85 °C)
Dimensions: 0.85 X 0.80 in (2.16 X 2.03 cm)
Application Ideas
Mobile altimeter / barometer systems
Rate of climb and descent indicator (RCDI)
Height sensing
Navigation
Weather station
Altitude hold for UAVs
IMU builds
Downloads & Resources
More resources, example code, the device schematic, and open-source hardware files are available from
the 29124 product page at
www.parallax.com.
Copyright © Parallax Inc.
Altimeter Module MS5607 (#29124)
v1.0 11/3/2011 Page 1 of 5
Quick-Start Guide
The following is a very basic procedure to get started initializing and reading values from the Altimeter
Module. Example test code can be found on the 29124 product page at www.parallax.com.
This module’s default communication setup is I²C. Use of SPI communication is configured by pulling the
PS pin low. See the datasheet for SPI configuration and use.
1. With main power off, make the proper connections between the module and a microcontroller as
shown below. The voltage connected to the VIN pin should be the same as the voltage powering
the microcontroller communicating with the device.
2. Power on the device and load the sample code provided on our product page.
NOTE: The SDA pin is connected to a bi-directional level shifting IC, used to translate the lower
I/O voltage of the MS5607 to the possibly higher voltage used by an externally connected device.
This particular level shifter has built-in pull-up resistors to each supply rail so it can be driven by
open drain outputs for I
2
C; but can also be driven low/high for SPI protocol. The CLK, PS and CS
pins operate exclusively as inputs, so a simpler level shifting circuit with a resistor and Schottky
diode is used. For the SDO pin another simple level shifting circuit is used along with a MOSFET
and two resistors.
In summary, there is no need for any external hardware to operate.
Precautions
This sensor is moisture sensitive and was manufactured with “no-clean” solder paste. Please take
steps to protect unit in wet environments.
The pressure sensor is light sensitive; direct light will give false readings. Indirect light is okay.
Calibration
There is no need to calibrate the module since every sensor is individually factory calibrated at two
temperatures and two pressures. These calibration tests are stored on the sensor itself and are part of
the onboard ROM data.
Copyright © Parallax Inc.
Altimeter Module MS5607 (#29124)
v1.0 11/3/2011 Page 2 of 5
Device Information
All the features of the MS5607 Altimeter IC are covered in full detail in the device datasheet.
Pin Definitions and Ratings
Pin
1
2
3
4
5
6
Name
GND
VIN
PS
SCL
SDA/SDI
SDO
Type
G
P
I
I
IO
O
Function
0 V supply, ground pin
Supply voltage from +3.3 to +6.5 VDC
Protocol select: PS high (VDD) I
2
C; PS low (GND) SPI
I
2
C & SPI serial clock (SCL)
Serial data input / I2C data IO
SPI serial data output (SDO)
7
CS
I
Chip select (active low), internal connection
Pin Type: P = Power, G = Ground, I = Input, O = Output
Module Dimensions
Copyright © Parallax Inc.
Altimeter Module MS5607 (#29124)
v1.0 11/3/2011 Page 3 of 5
Theory of Operation
The MS5607 consists of a piezo-resistive sensor and a sensor interface IC. The main function of the
MS5607 is to convert the uncompensated analogue output voltage from the piezo-resistive pressure
sensor to a 24-bit digital value, as well as providing a 24-bit digital value for the temperature of the
sensor.
For details on pressure and temperature calculations, please refer to the data sheet and to application
note #501 located on the 29124 product page at
www.parallax.com.
In order to obtain best accuracy over temperature range, particularly in low temperature, it is
recommended to compensate the non-linearity over the temperature. For a full description and flow chart
on setting up this compensation, see page 9 of the datasheet located on the Altimeter Module’s product
page at
www.parallax.com.
Pressure Output Characteristics (VDD = 3V, T = 25°C)
Parameter
Operating Pressure
Range
Extended Pressure
Range
Total Error band,
no autozero
Total Error band,
autozero at one
pressure point
Conditions
Full Accuracy
Linear Range of ADC
at 25°C, 700..1100 mbar
at 0..50°C, 300..1100 mbar
at -20..85°C, 300..1100 mbar
at -40..85°C, 300..1100 mbar
at 25°C, 700..1100 mbar
at 0..50°C, 300..1100 mbar
at -20..85°C, 300..1100 mbar
at -40..85°C, 300..1100 mbar
Oversampling Ratio (OSR)
4096
2048
1024
512
256
Minimum
300
10
-1.5
-2.0
-3.5
-6.0
-0.5
-1.0
-2.5
-5.0
0.024
0.036
0.054
0.084
0.130
-1
Typical
Maximum
1100
1200
+1.5
+2.0
+3.5
+6.0
+0.5
+1.0
+2.5
+5.0
Unit
mbar
Resolution RMS
Long-term stability
Table data is taken from the MS5607 datasheet.
mbar/yr
Temperature Output Characteristics (VDD = 3V, T = 25°C)
Conditions
at 25°C
Absolute Accuracy
-20..85°C
-40..85°C
Oversampling Ratio (OSR)
4096
2048
Resolution RMS
1024
512
256
Table data is taken from the MS5607 datasheet.
Parameter
Minimum
-0.8
-2.0
-4.0
Typical
Maximum
+0.8
+2.0
+4.0
Unit
0.002
0.003
0.005
0.008
0.012
°C
Copyright © Parallax Inc.
Altimeter Module MS5607 (#29124)
v1.0 11/3/2011 Page 4 of 5
Communication Protocol
The Altimeter Module has built in two types of serial interfaces: SPI and I
2
C. Pulling the Protocol Select
pin PS low selects the SPI protocol. The module pulls the PS high making the default communication
protocol I
2
C. For details on use of these communication protocols, please refer to the datasheet located
on the 29124 product page.
Example Code
Example code is available for download from the 29124 product page at
www.parallax.com.
C Code
Please see application note “APPNote_520_C_code.pdf” on the 29124 product page for C code examples
using Measurement Specialties Altimeters.
Propeller
™
P8X32A
The Altimeter_Demo_and_Driver.zip contains 29124_simple_altimeter_demo.spin file which is a simple
demonstration showing altitude with a configurable starting altitude. Also contained in the zip file is an
HTML file “29124_altimeter.html” that goes over in detail about the altimeter driver used in the demo
code.
The Demo programs use Parallax Serial Terminal to display the device output. The object and the
Parallax Serial Terminal itself are included with the with the Propeller Tool v1.2.7 or higher, which is
available from the Downloads link at www.parallax.com/Propeller.
Copyright © Parallax Inc.
Altimeter Module MS5607 (#29124)
v1.0 11/3/2011 Page 5 of 5
