Difference between revisions of "Embedded System Tutorial File I/O"
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| + | Socialledge is moving to two portals. | ||
| + | * The Wiki will remain here for general references about the SJ-One board, and to document student reports. | ||
| + | * The bookstack will now be used for SJSU assignments | ||
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| + | [http://books.socialledge.com/books/embedded-drivers-real-time-operating-systems/chapter/lesson-watch-dogs This article has been moved here] | ||
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In this project, we will attempt to "combine" all the FreeRTOS knowledge into a single assignment. | In this project, we will attempt to "combine" all the FreeRTOS knowledge into a single assignment. | ||
| − | After completing the assignment, you will get a | + | After completing the assignment, you will get a sense of how the CPU is utilized, and how to use a new FreeRTOS event group API. All together, you should achieve a better sense of designing your tasks and using the File I/O for debugging purposes. |
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# Create a '''<code>producer task</code>''' that takes 1 light sensor value every 1ms. | # Create a '''<code>producer task</code>''' that takes 1 light sensor value every 1ms. | ||
| − | #* | + | #* After collecting 100 samples (after 100ms), compute the average. |
#* Write average value every 100ms (avg. of 100 samples) to the '''<code>sensor queue</code>'''. | #* Write average value every 100ms (avg. of 100 samples) to the '''<code>sensor queue</code>'''. | ||
#* Use medium priority for this task | #* Use medium priority for this task | ||
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#* Open a file (sensor.txt), and append the data to an output file on the SD card. | #* Open a file (sensor.txt), and append the data to an output file on the SD card. | ||
#* Save the data in this format: '''<code>printf("%i, %i\n", time, light)"</code>''' | #* Save the data in this format: '''<code>printf("%i, %i\n", time, light)"</code>''' | ||
| − | #* | + | #* Note that if you write and close a file every 100ms, it may be very inefficient, so try to come up with a better method such that the file is only written once a second or so... |
#* Use medium priority for this task | #* Use medium priority for this task | ||
# At the end of the loop of each task, set a bit using FreeRTOS event group API. | # At the end of the loop of each task, set a bit using FreeRTOS event group API. | ||
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# Create a '''<code>watchdog task</code>''' that monitors the operation of the two tasks. | # Create a '''<code>watchdog task</code>''' that monitors the operation of the two tasks. | ||
#* Use high priority for this task. | #* Use high priority for this task. | ||
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#* Use a timeout of 1 second, and wait for all the bits to set. If there are two tasks, wait for bit1, and bit2 etc. | #* Use a timeout of 1 second, and wait for all the bits to set. If there are two tasks, wait for bit1, and bit2 etc. | ||
#* If you fail to detect the bits are set, that means that the other tasks did not reach the end of the loop. | #* If you fail to detect the bits are set, that means that the other tasks did not reach the end of the loop. | ||
#* In the event of failed to detect the bits, append a file (stuck.txt) with the information about which task may be "stuck" | #* In the event of failed to detect the bits, append a file (stuck.txt) with the information about which task may be "stuck" | ||
#* Open the file, append the data, and close the (stuck.txt) file to flush out the data immediately. | #* Open the file, append the data, and close the (stuck.txt) file to flush out the data immediately. | ||
| + | #* Extra Credit: Every sixty seconds, save the CPU usage info to a file named "cpu.txt". See terminal command "infoHandler" for reference. Open the file, write the file, and close it immediately so the data is immediately flushed. | ||
# Create a terminal command to "suspend" and "resume" a task by name. | # Create a terminal command to "suspend" and "resume" a task by name. | ||
#* "task suspend task1" should suspend a task named "task1" | #* "task suspend task1" should suspend a task named "task1" | ||
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# Suspend the producer task. The watchdog task should display a message and save relevant info to the SD card. | # Suspend the producer task. The watchdog task should display a message and save relevant info to the SD card. | ||
# Let the system run for a while, and note down the CPU usage in your text file. | # Let the system run for a while, and note down the CPU usage in your text file. | ||
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What you created is a "software watchdog". This means that in an event when a loop is stuck, or a task is frozen, you can save relevant information such that you can debug at a later time. | What you created is a "software watchdog". This means that in an event when a loop is stuck, or a task is frozen, you can save relevant information such that you can debug at a later time. | ||
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Latest revision as of 20:10, 25 January 2019
Socialledge is moving to two portals.
- The Wiki will remain here for general references about the SJ-One board, and to document student reports.
- The bookstack will now be used for SJSU assignments
This article has been moved here
