issue in running 1 micro second timer
Is this a FreeRTOS question, or a question about how to use a hardware timer on a specific chip? If it is a FreeRTOS question please say something about what the timer is going to be doing, and what you are trying to achieve by having it run ever uS.
Running code from a timer that interrupts every 1us is going to be a VERY big load on your system, so I don’t think that is what you really mean, or you don’t understand you real needs.
If you want 1us resolution for some timing, you will need to use some hardware timer that your code sets up for that, and you will need to take into account the overhead associated with the setup and entry of the ISR. That speed operation tends to NOT be based on OS level operations, but code directly run inside an ISR.