How to use external interrupt with FreeRTOS

I use LPC2148 with FreeRTOS and I want to test xSemaphoreGiveFromISR function. I try to use only external interrupt it work but when I use FreeRTOS it doesn’t work. I guess this problem is happen because startup file. I use one startup file with one project it can run freeRTOS but I use another startup file is cannot run freeRTOS but can run external interrupt. I check the different between 2 files I found this                          ISR_Stack_Size  EQU     (UND_Stack_Size + SVC_Stack_Size + ABT_Stack_Size +  
                         FIQ_Stack_Size + IRQ_Stack_Size) in the project that can run external interrupt but FreeRTOS doesn’t work.
How can I do with startup file? I use Keil  IDE Thank you

How to use external interrupt with FreeRTOS

I think the LPC2138 demo uses an external interrupt connected to a button on the Crossfire board. Can you copy that?