ADXL202EB232 Analog Devices Inc, ADXL202EB232 Datasheet - Page 4

• Manufacturer Part Number: ADXL202EB232
• Manufacturer: Analog Devices Inc

Specifications of ADXL202EB232

• Lead Free Status / Rohs Status: Not Compliant

4
Table 3: Data Encoding
PWM % = (256 * MSB + LSB) / 100.0
COMPONENTS
The demo board consists of an ADXL202
accelerometer, a 16C63 Microchip microcontroller,
an ADM666 for voltage regulation of the RS-232
RTS signal, an ADM232 for RS232 interface, and a
crystal. Note that many of these components are
required only to support the RS-232 interface. In a
stand-alone, (non-232) board, often only the
ADXL202 and the Microchip controller will be
necessary.
RSET Resistor
To change the PWM frequency, the resistor labeled
R6 can be changed. Also there is a through-hole
resistor location RSET. Note: since R6 and RSET
are in parallel, one should only place a resistor in
only one of the locations. Please consult the Analog
Devices ADXL202 datasheet for values. The default
value of R6 sets the PWM frequency to 2.0KHz
X CAP/Y CAP Capacitors
The analog filtering for the X and Y accelerometers
are set by C15 and C11 respectively. There are
through-hole capacitors locations labeled X CAP and
Y CAP. Note: Since the pairs C15, X CAP and
C11, Y CAP are in parallel, one should only place
capacitors in one of the paired locations. Please
consult the Analog Devices ADXL202 datasheet for
more specifics. The default values of C15 and C11
0-255
Y Axis LSB
set the analog cut-off frequency to 106Hz for both
the X and Y accelerometers.
Troubleshooting
The ADXL202EB-232A is powered through your
computer's COM port using the DTS line. Some
computers do not supply enough power to the board.
Other computers require that the serial port is active
before the DTS line is forced high. If you do not see
the red LED flash on the board when you first plug it
into the serial port, this is most likely the problem.
To activate the com port, attempt to connect to the
com port through the software. After the connection
fails, press the reset button on the demo board, then
attempt to reconnect. If all else fails, try the board
on another computer.
If you do not get the "connected" button to turn
green on the evaluation software check the following
things:
Cannot get a consistent constant sampling rate:
Spirit Level display is showing NaN or showing
inconsistent results.
The correct COM port is selected. Try
switching the COM port setting on the software
to make sure.
Press the Reset Button. Verify that the LED on
the demo board flashes.
Close all other programs.
Datalog to a file and then do post-processing.
Set the datalog rate the same as the update rate.
Calibrate the demo board before using the Spirit
Level display