Callback function use in Usart

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sp_usa1
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Posted by sp_usa1: Sat. Nov 19, 2016 - 07:13 AM
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Hi,

I want to use callback function when RX interrupt occur in USART.

Just print any values after Rx interrupt.

Thanks

harman

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AVR Microcontrollers, megaAVR and tinyAVR
Last Edited: Sat. Nov 19, 2016 - 07:27 AM
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Bronze Markjs
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Posted by js: Sat. Nov 19, 2016 - 07:26 AM
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This has NOTHING to do with Studio bugs which this forum is for, I'll move the thread. No idea which chip you are using so I'll move it to the mega and tiny forum for now.

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Gold Markclawson
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Posted by clawson: Sat. Nov 19, 2016 - 12:46 PM
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Callbacks from ISRs are not a great idea. Just buffer the received data somewhere and if necessary set a flag to the foreground consumer code. 

 

If you do callback from an ISR the called code will run in the context of the interrupted disabled ISR. 

 

On AVR Tiny/Mega where there are no interrupt priorities you need all your ISRs to complete in microseconds. 

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sp_usa1
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Posted by sp_usa1: Sat. Nov 19, 2016 - 01:56 PM
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We have to do something 'registration' to buffer or at receiver side?

harman

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Bronze Markawneil
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Posted by awneil: Sat. Nov 19, 2016 - 04:10 PM (Reply to #4)
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sp_usa1 wrote:

We have to do something 'registration' to buffer or at receiver side?

Sorry, I have no idea what you mean by that - please explain.

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Gold Markclawson
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Posted by clawson: Sat. Nov 19, 2016 - 04:49 PM
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Google "ring buffer" or perhaps "FIFO". Almost every interrupt driven AVR UART TX/RX is based on FIFOs

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Bronze Markawneil
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Posted by awneil: Sat. Nov 19, 2016 - 05:33 PM (Reply to #6)
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clawson wrote:

Google "ring buffer" or perhaps "FIFO". 

aka "Circular Buffer"

 

Almost every interrupt driven AVR UART TX/RX is based on FIFOs

And not just AVRs: almost every interrupt driven UART TX/RX is based on FIFOs!

Top Tips:

  1. How to properly post source code - see: https://www.avrfreaks.net/comment... - also how to properly include images/pictures
  2. "Garbage" characters on a serial terminal are (almost?) invariably due to wrong baud rate - see: https://learn.sparkfun.com/tutorials/serial-communication
  3. Wrong baud rate is usually due to not running at the speed you thought; check by blinking a LED to see if you get the speed you expected
  4. Difference between a crystal, and a crystal oscillator: https://www.avrfreaks.net/comment...
  5. When your question is resolved, mark the solution: https://www.avrfreaks.net/comment...
  6. Beginner's "Getting Started" tips: https://www.avrfreaks.net/comment...
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sp_usa1
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Posted by sp_usa1: Sun. Nov 20, 2016 - 11:26 AM (Reply to #5)
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I want to transmit and receive data by using TX and RX interrupt in USART,for interfacing of atmega32

 

harman

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sp_usa1
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Posted by sp_usa1: Sun. Nov 20, 2016 - 11:30 AM
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Please post sample code for Usart for receiption and transmission.

harman

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Gold Markclawson
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Posted by clawson: Sun. Nov 20, 2016 - 12:00 PM
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Try the tutorial forum.

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