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resources:quick-start:adxl313_quick_start_guide [16 Jul 2020 23:29] – added DATA FORMAT section Pablo del Corroresources:quick-start:adxl313_quick_start_guide [16 Jul 2020 23:58] – [INITIALIZATION] Pablo del Corro
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 The interrupt behavior, latch high or latch low, can be configured through the DATA_FORMAT register. Refer to the ADXL313 data sheet for details. The interrupt behavior, latch high or latch low, can be configured through the DATA_FORMAT register. Refer to the ADXL313 data sheet for details.
  
 +<note tip>
 +Always make set the ADXL313 in Standby mode first before configuring any register. 
 +</note>
 ==== DATA FORMAT ==== ==== DATA FORMAT ====
 The ADXL313 registers length is 8 bits, while its acceleration in full resolution is 13 bits. Thus the acceleration data of each axis is stored in two registers. For example, for X-axis DATAX0 is the low byte register and DATAX1 is the high byte register. Once acceleration data is acquired from data registers, the user must reconstruct the data as a 16-bits word length.  The ADXL313 registers length is 8 bits, while its acceleration in full resolution is 13 bits. Thus the acceleration data of each axis is stored in two registers. For example, for X-axis DATAX0 is the low byte register and DATAX1 is the high byte register. Once acceleration data is acquired from data registers, the user must reconstruct the data as a 16-bits word length. 
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 {{ :resources:quick-start:xl-dataconstruction.png?nolink&400 |}} {{ :resources:quick-start:xl-dataconstruction.png?nolink&400 |}}
  
-<note tip> 
 In programming language this will be equivalent to:  In programming language this will be equivalent to: 
 <code> <code>
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 </code> </code>
 with X_16bits a variable defined as uint16.  with X_16bits a variable defined as uint16. 
-</note> 
  
-Make sure to zero the unwanted MSB (14th to 16th bit) by doing: +Also make sure to zero the unwanted MSB (14th to 16th bit) by doing: 
  
 <code> <code>
-X_16bits  = X_16bits & 0x1FFF;+X_raw  = X_16bits & 0x1FFF;
 </code> </code>
- +where **X_raw** is uint16 that contains actual acceleration information formatted as **two's complement**. 
-<note important>The ADXL313 uses two's complement data format.</note>+
  
 The two's complement function can be implemented with the following code: The two's complement function can be implemented with the following code:
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 } }
 </code> </code>
-For this example, the argument **value** will be X_16bits and the argument **bits** will be 13 (full resolution). +For this example, the argument **value** will be X_raw and the argument **bits** will be 13 (full resolution). 
  
 To calculate the acceleration value in units of //g//, multiply the two's complement value obtained times the Scale Factor (1/sensitivity, units: [g]/LSB) at the given range and resolution. For this example, the Scale Factor is 4 [g]/ 1024 LSB which is equal to 3.9[m//g//]/LSB. To calculate the acceleration value in units of //g//, multiply the two's complement value obtained times the Scale Factor (1/sensitivity, units: [g]/LSB) at the given range and resolution. For this example, the Scale Factor is 4 [g]/ 1024 LSB which is equal to 3.9[m//g//]/LSB.
  
-<note important>Always review the [[ADI>media/en/technical-documentation/data-sheets/ADXL313.pdf|ADXL313 datasheet]] for detailed information</note>  +In code this is:  
 +<code> 
 +X_g = (twos_complement(X_raw,13))*0.0039; 
 +</code>  
 +where **X_g** is the X-axis acceleration in units of //g//. 
 + 
 +<note tip>Always review the [[ADI>media/en/technical-documentation/data-sheets/ADXL313.pdf|ADXL313 datasheet]] for detailed information</note>  
  
resources/quick-start/adxl313_quick_start_guide.txt · Last modified: 16 Jul 2020 23:59 by Pablo del Corro

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