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use of MUTEX in ISR

Question asked by MattZ on Apr 21, 2011
Latest reply on May 6, 2011 by BrianW

Hi All,


I'm working on a project where I have an ISR reading ascii (NMEA formatted) data from a UART. My plan is to have a separate thread parse the ascii data and do something with the data. The ISR reads a character from the UART and puts it into a buffer. If the character is a new_line then it will notify the other thread to do its thing via a semaphore.


I plan to use two buffers so that one sentance could be collected by the ISR, while the other thread parses the sentance in the other buffer.


My question is can/should I use a mutex to protect each buffer in the ISR? If this were two ordinary threads, I would think that each thread would acquire the mutex associated with a particular buffer when operating on a particular buffer.


I noticed on page 5-235 of the VisualDSP++ 5.0 Kernel (VDK) User’s Guide that there is a list of ISR assembly macros. They include semaphores but not mutexes.


Any advice would be appreciated.


Thanks in advance