Difference between revisions of "Embedded System Tutorial UART"

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(Introduction)
 
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Socialledge is moving to two portals. 
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*  The Wiki will remain here for general references about the SJ-One board, and to document student reports.
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*  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-uart This article has been moved here]
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== Introduction ==
 
== Introduction ==
 
The objective of this lesson is to understand UART, and use two boards and setup UART communication between them.
 
The objective of this lesson is to understand UART, and use two boards and setup UART communication between them.
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A micrcontroller can have multiple UARTs in its hardware, and usually UART0 is interfaced to a "USB to serial" converter chip which is then connected to your computer.  In this exercise, you will write a driver for UART-2 and attempt to communicate between two boards.
 
A micrcontroller can have multiple UARTs in its hardware, and usually UART0 is interfaced to a "USB to serial" converter chip which is then connected to your computer.  In this exercise, you will write a driver for UART-2 and attempt to communicate between two boards.
  
I encourage you to fully read this article first, and here is a video about the UART0 tutorial.  This is a FAST PACED video, so learn to pause the video and look over your LPC user manual frequently :)
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I encourage you to fully read this article first, and here is a video about the UART0 tutorial.  This is a FAST PACED video, so learn to pause the video and look over your LPC user manual frequently :) '''Note that I forgot to configure the PINSEL registers, which are covered by this tutorial below.'''
[[https://www.youtube.com/watch?v=RU_NUPprx2Y]]
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*  [https://www.youtube.com/watch?v=RU_NUPprx2Y UART Driver Video]
  
 
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     LPC_UART0->LCR = (1 << 7); // Enable DLAB
 
     LPC_UART0->LCR = (1 << 7); // Enable DLAB
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    /* See the formula picture to get more info.
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    * Default values of fractional dividers simplifies the equation
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    * Warning: You need to set DLM/DLL correctly, but if divider is small enough, it will fit inside DLL
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    */
 
     LPC_UART0->DLM = 0;
 
     LPC_UART0->DLM = 0;
    /* See the formula picture to get more info.
 
    * Default values of fractional dividers simplifies the equation */
 
 
     LPC_UART0->DLL = CPU_CLOCK / (16 * 9600) + 0.5);
 
     LPC_UART0->DLL = CPU_CLOCK / (16 * 9600) + 0.5);
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     LPC_UART0->LCR = 3;        // 8-bit data
 
     LPC_UART0->LCR = 3;        // 8-bit data
 
}
 
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== Assignment ==
 
== Assignment ==
*  Locate the physical pins for a UART that is not already used by your board
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* <b>Assignment Outline</b>
* Configure the PINSEL to use the pins for UART Rx/Tx
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*: Form 2 people teams for this assignment.
* Initialize your UART at any baud rate
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*: Write a driver for UART2 or UART3
* Write uart_putchar(char) and uart_getchar() functions
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*: Do not use the pre-built driver or Uart2/3 class
* Interface your UART with someone else's board, and test the communication.
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*: Connect your UART to your partner's UART (to his board)
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*: Prove that you can send/receive data across multiple boards.
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*: Upload Logic Analyzer Screenshot for the UART Frame.
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* <b>Extra Credit</b>:
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*: Use Uart interrupt to queue the received data to avoid polling. You just need to enable UART RX interrupt and then hookup an interrupt callback to do the receive.
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* <b>Steps</b>
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*: Locate the physical pins for a UART that is not already used by your board
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*: Configure the PINSEL to use the pins for UART Rx/Tx
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*: Initialize your UART at any baud rate
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*: Write uart_putchar(char) and uart_getchar() functions
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*: Interface your UART with someone else's board, and test the communication.
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Latest revision as of 20:05, 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