Changeset 288

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Timestamp:
09/23/08 19:51:37 (5 years ago)
Author:
atorf
Message:

Added documentation for COM_ReadI2C

Location:
branches/atorf/RWTHMindstormsNXT
Files:
2 modified

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  • branches/atorf/RWTHMindstormsNXT/COM_ReadI2C.m

    r273 r288  
    11function ReturnBytes = COM_ReadI2C(Port, RequestLen, DeviceAddress, RegisterAddress, varargin) 
    2  
     2% Requests and reads sensor data via I2C from a correctly configured digital sensor. 
     3% 
     4% Syntax 
     5%   |ReturnBytes = COM_ReadI2C(Port, RequestLen, DeviceAddress, RegisterAddress)| 
     6% 
     7%   |ReturnBytes = COM_ReadI2C(Port, RequestLen, DeviceAddress, RegisterAddress, handle)| 
     8% 
     9% Description 
     10%    This function is used to retrieve data from digital sensors (like the 
     11%    ultrasonic) in a comfortable way. It is designed as a helping function 
     12%    for developers wanting to access new sensors. For already implemented 
     13%    sensors (e.g. ultrasound, as well as HiTechnic's acceleration and  
     14%    infrared sensors), use the provided high-level functions such as 
     15%    |GetUltrasonic|, |GetInfrared|, etc. 
     16% 
     17%    For I2C communication, usually the |NXT_SetInputMode| command has to 
     18%    be used with the |LOWSPEED_9V| or |LOWSPEED| setting. Afterwards, 
     19%    commands can be send with |NXT_LSWrite|. Once a sensor is correctly 
     20%    working, i.e. has data available, you can use this function to 
     21%    retrieve them. 
     22% 
     23%    In |COM_ReadI2C(Port, RequestLen, DeviceAddress, RegisterAddress)|, 
     24%    |Port| is the sensor-port the sensor is connected to. |RequestLen| 
     25%    specifies the amount of bytes you want to retrieve. For ultasound, 
     26%    this is 1. |DeviceAddress| is the sensor's address on the I2C bus. 
     27%    This sometimes can be changed, but not for the ultrasonic sensor. 
     28%    Default value is 0x02 (2 in decimal). Finally, |RegisterAddress| is 
     29%    the address where you want to read data from. For the ultrasound and 
     30%    many other sensors, the "data section" starts at 0x24 (66 in decimal). 
     31% 
     32%    As last argument you can pass a valid NXT-handle to be used from this 
     33%    function. If no handle is passed, the default set by 
     34%    |COM_SetDefaultNXT will be used. 
     35% 
     36%    *Returns:* |ReturnBytes|, byte-array (column vector) of uint8 
     37%    This array contains the raw sensor-data you requested. How to 
     38%    interpret them depends on the sensor. If communication failed (even 
     39%    after automatic retransmission) -- e.g. when the sensor get's 
     40%    disconnected while in use -- an empty vector |[]| will be returned. 
     41% 
     42% Note 
     43%    Please note that the return values of this function are of type uint8. 
     44%    You have to convert them to double (using |double()|) before 
     45%    performing calculations with them, otherwise you might get unexpected 
     46%    results! 
     47% 
     48%    The sensor you are addressing with this command has to be correctly 
     49%    opened and initialized of course -- otherwise no valid data can be 
     50%    received. 
     51% 
     52% Example 
     53%    This example opens and reads the ultrasonic sensor 
     54%+   port = SENSOR_1; 
     55%+   handle = COM_OpenNXT('bluetooth.ini', 'check'); 
     56%+ 
     57%+   OpenUltrasonic(port); 
     58%+    
     59%+   % retrieve 1 byte from device 0x02, register 0x42 
     60%+   data = COM_ReadI2C(port, 1, uint8(2), uint8(66)); 
     61%+    
     62%+   if isempty(data) 
     63%+       DistanceCM = -1; 
     64%+   else 
     65%+       % don'f forget this double()!!! 
     66%+       DistanceCM = double(data(1)); 
     67%+   end%if 
     68% 
     69% 
     70% See also: NXT_LSWrite, NXT_LSRead, NXT_LSGetStatus, NXT_SetInputMode, OpenUltrasonic, 
     71% GetUltrasonic, SENSOR_1, SENSOR_2, SENSOR_3, SENSOR_4 
     72% 
     73% 
     74% Signature 
     75%   Author: Linus Atorf (see AUTHORS) 
     76%   Date: 2008/09/23 
     77%   Copyright: 2007-2008, RWTH Aachen University 
     78% 
    379 
    480 

  • branches/atorf/RWTHMindstormsNXT/NXT_PlayTone.m

    r140 r288  
    5252% check if bluetooth handle is given; if not use default one 
    5353if nargin > 2 
    54         handle = varargin{1}; 
     54    handle = varargin{1}; 
    5555else 
    5656    handle = COM_GetDefaultNXT;