SOURCEFORGE » RALF » 2015 Erasure codes for Cubesat missions

h1. III - Advanced Project.

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h2. 1. Adapting project to elementary task.

See [[Wiki#"3. Creation of a simple MPLAB X IDE project"|Tutorial page]] for project bases

In this part, you will have to modify particular files of the previous Test/.

h3. 1.1 Integrating C Source files into task.

* task_name.c stating _void task_name (void) { ... }_.

Here you can either call the C main function in the task_name function or adapting your main file into a task.

* task_name.h stating _extern void task_name (void);_ and other intern functions.

h3. 1.2 

* tasks.h defining OSTCBP of all predifined tasks (way of specifying a pointer to a particular Salvo _Task Control Block_). More information available on Salvo User Manual.

* task_cmd.c which is a tool provided by Test/ that allows to resume/stop your task.

!task_cmd.png!

* main.c which is the basic implementation to call your task(s).

!main.png!

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h2. 2. Integration of a Reed-Solomon encoder/decoder.

A highly convenient implementation of a Reed-Solomon code is available on "RS Code Website":http://rscode.sourceforge.net/ and will be integrated in the following.

h3. 2.1 Presentation of Reed-Solomon.

h3. 2.2 Task Example.

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h2. 3. Displaying results.

h3. 3.1 In simulation.

p=. !CodingWin3.png!

*Message of 87 characters*

p=. !CodingWin2.png!

*Code of adding errors*

p=. !UART1.png!

*Checking Output UART Window*

p=. !CodingWin1.png!

*Displayed result*

h3. 3.2 On board.

|_.-                    |_.Char       |_.Code ASCII  |_.Hexadecimal |_. Binary       |

|_.Codeword             |=. 2         |=. 50         |=. 0x32       |   0b00110010   |

|_.Erroneous Codeword   |=. 3         |=. 51         |=. 0x33       |   0b00110011   |

!LEDs_resized.png! !LEDs_error_resized.png! !LEDs_resized.png!

__________________ *a. Codeword : 0bXX110010* ________________________ *b. Erroneous codeword : 0bXX110011* ____________________ *c. Corrected codeword : 0bXX110010* ______________

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h2. 4. Measurement of encoding/decoding time.

p=. !Clock1.png!

*1000 ticks per milliseconds*

p=. !Clock2.png!

*Time measurement of data encoding*

p=. !Clock3.png!

*Printing clock data*

p=. !Time_RS_resized.PNG!

*Chart of Reed Solomon time measurement*