# Send Message From ISR -port LPC2212

**URL:** <https://forums.freertos.org/t/send-message-from-isr-port-lpc2212/2054>\
**Category:** Kernel\
**Created:** [December 1, 2008, 2:23pm UTC](https://forums.freertos.org/t/send-message-from-isr-port-lpc2212/2054 "2008-12-01T14:23:36Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [December 1, 2008, 2:23pm UTC](https://forums.freertos.org/t/send-message-from-isr-port-lpc2212/2054/1 "2008-12-01T14:23:36Z")

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**[verretj](https://sourceforge.net/u/verretj/)** wrote on [Monday, December 01, 2008](https://sourceforge.net/p/freertos/discussion/382005/thread/5afd8edd/#161a):

Hello,

I’m trying to make a serial driver. Therefore I have to send a message from an ISR.  
This message sometimes awake a different task from the one it is interrupting, and sometimes the same task that was interrupted.  
Referring to the documentation I have to use taskYIELD\_FROM\_ISR () when the task has been awaken. But It is apparently not defined&nbsp; in the code.  
How can I do then.  
I tried without it but I can merely send an receive characters once.  
And I tried with taskYIELD and portYIELD\_FROM\_ISR() which does not work at all  
What should I do and where is this&nbsp; taskYIELD\_FROM\_ISR () defined?

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<div class="post-metadata">

**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [December 1, 2008, 2:34pm UTC](https://forums.freertos.org/t/send-message-from-isr-port-lpc2212/2054/2 "2008-12-01T14:34:32Z")

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**[davedoors](https://sourceforge.net/u/davedoors/)** wrote on [Monday, December 01, 2008](https://sourceforge.net/p/freertos/discussion/382005/thread/5afd8edd/#161a/f67f):

There is inconsistency in the naming of this macro. Depending on the compiler you are using it might be called portEND\_SWTICHING\_ISR. Look at the example interrupt service routines that came with the port you are using to see how it is done.