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pmod:pmodacl:reference-manual [2022/09/13 17:12] – changed forum.digilentinc.com to forum.digilent.com jeff.greenberg_ni.compmod:pmodacl:reference-manual [2022/10/04 11:38] (current) – external edit 127.0.0.1
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 +====== Pmod ACL Reference Manual ======
  
 +The Digilent Pmod ACL (Rev. E) is a 3-axis digital accelerometer module powered by the [[http://www.analog.com/static/imported-files/data_sheets/ADXL345.pdf|Analog Devices ADXL345]]. 
 +
 +{{Digilent Image Gallery 
 +| image = {{ :reference:pmod:pmodacl:pmodacl-0.png?direct |}}
 +| image = {{ :reference:pmod:pmodacl:pmodacl-1.png?direct |}}
 +| image = {{ :reference:pmod:pmodacl:pmodacl-2.png?direct |}}
 +| image = {{ :reference:pmod:pmodacl:pmodacl-3.png?direct |}}
 +}}  
 +
 +
 +== Download This Reference Manual == 
 +  * {{:reference:pmod:pmodacl:pmodacl_rm.pdf| PDF}}
 +
 +===== Features =====
 +  * 3-axis, ±2/4/8/16g accelerometer
 +  * User-selectable resolution 
 +  * Activity/inactivity monitoring  
 +  * Single/double-tap and free-fall detection 
 +  * Small PCB size for flexible designs 1.0 in × 0.8 in (2.5 cm × 2.0 cm) 
 +  * 12-pin Pmod port with SPI interface and 2×4-pin I²C interface
 +  * Follows Digilent Pmod Interface Specification Type 2A
 +  * Library and example code available in resource center
 +
 +----
 +=====Functional Description =====
 +The %%Pmod ACL%% utilizes [[http://www.analog.com/static/imported-files/data_sheets/ADXL345.pdf|Analog Devices ADXL345]] to provide high resolution acceleration changes including inclination changes of less than 1.0°. With free fall and single/double tap detection capabilities, the %%Pmod ACL%% can be configured to take measurements on the user's whim.
 +
 +----
 +===== Interfacing with the Pmod=====
 +The %%Pmod ACL%% communicates with the host board via the [[pmod:communication_protocols:spi|SPI protocol]] or the [[pmod:communication_protocols:i2c|I²C protocol]]. SPI communication is enabled when the Chip Select line is driven low; conversely, the I²C protocol is enabled when the Chip Select line is driven to a logic level high voltage. An interrupt can be triggered whenever a measured axis acceleration data is over a user defined threshold limit. A data stream setting the threshold activity to a value of 250 mg and Interrupt 1 to be triggered whenever the X and Y axis exceeds the threshold level through SPI is provided below:
 +
 +
 +^  Read/~Write  ^  Multi-byte  ^  6-bit Threshold Activity Address  ||||||
 +|  0  |  0  |  1  |  0  |  0  |  1  |  0  |  0  |
 +^  8 bits of Threshold Activity data (62.5 mg/LSB scale)  ||||||||
 +|  0  |  0  |  0  |  0  |  0  |  1  |  0  |  0  |
 +^  Read/~Write  ^  Multi-byte  ^  6-bit Activity/Inactivity Control Address  ||||||  
 +|  0  |  0  |  1  |  0  |  0  |  1  |  1  |  1  |
 +^  Activity/Inactivity Control Settings  ||||||||
 +|  ACT ac/dc  |  ACT X  |  ACT Y  |  ACT Z  |  INACT ac/dc  |  INACT X  |  INACT Y  |  INACT  Z  |
 +|  0  |  1  |  1  |  0  |  0  |  0  |  0  |  0  |
 +^  Read/~Write  ^  Multi-byte  ^  6-bit Interrupt Enable Address  ||||||  
 +|  0  |  0  |  1  |  0  |  1  |  1  |  1  |  0  |
 +^  8 bits of Which Interrupt Sources Are Enabled  ||||||||
 +|  Data Ready  |  Single Tap  |  Double Tap  |  Activity  |  Inactivity  |  Free Fall  |  Watermark  |  Overrun  |
 +|  0  |  0  |  0  |  1  |  0  |  0  |  0  |  0  |
 +
 +Once an interrupt has been generated, users may read the data registers (0x32 - 0x37) for the 10 bits of [[:twos_complement|two's complement data]] in the X, Y, and Z axes, respectively. The data in the two registers for each axis is right justified with sign extensions as the leading 6 bits. Reading the Interrupt source register (0x30) clears the activity interrupt bit D4. 
 +
 +Users may also follow the given [[pmod:pmodacl:start#example_projects|example code]] functions and demonstration to start collecting accelerometer data. 
 +
 +
 +==== Pinout Description Table ====
 +^  Pmod Header J1                                               |||||||   ^  Pmod Header J2  |||
 +^ Pin ^  Signal  ^  Description  | ^ Pin  ^  Signal  ^  Description  |:::^ Pin ^  Signal  ^  Description  |
 +|  1  |  ~CS   |  Chip Select  |:::|  7   |  INT2  |  Interrupt 2  |:::|  1, 5  |  SCL  |  Serial Clock  |
 +|  2  |  MOSI  |  Master-Out-Slave-In  |:::|  8   |  INT1  |  Interrupt 1  |:::|  2, 6  |  SDA  |  Serial Data  |
 +|  3  |  MISO  |  Master-In-Slave-Out  |:::|  9  |  NC  |  Not Connected  |:::|  3, 7  |  GND  |  Power Supply Ground  |
 +|  4  |  SCK  |  Serial Clock  |:::|  10  |  NC  |  Not Connected  |:::|  4, 8  |  VCC  |  Positive Power Supply  |
 +|  5  |  GND   |  Power Supply Ground  |:::|  11  |  GND   |  Power Supply Ground  |:::| |||
 +|  6  |  VCC   |  Power Supply (3.3V)  |:::|  12  |  VCC   |  Power Supply (3.3V)  |:::|:::|||
 +
 +Any external power applied to the %%Pmod ACL%% must be within 2.0V and 3.6V; it is strongly recommended that Pmod is operated at 3.3V.
 +----
 +===== Physical Dimensions =====
 +The pins on the pin header are spaced 100 mil apart. The PCB is 1 inch long on the sides parallel to the pins on the pin header and 0.8 inches long on the sides perpendicular to the pin header.
 +----
 +===== Additional Information =====
 +The schematics of the %%Pmod ACL%% are available {{reference:pmod:pmodacl:pmodacl_sch.pdf|here}}. Additional information about the accelerometer including communication modes and specific timings of the chip can be found by checking out its datasheet [[http://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf|here]]. 
 +
 +Example code demonstrating how to get information from the %%Pmod ACL%% can be found [[pmod:pmodacl:start#example_projects|here]].
 +
 +If you have any questions or comments about the %%Pmod ACL%%, feel free to post them under the appropriate section ("Add-on Boards") of the [[https://forum.digilentinc.com/|Digilent Forum]].