Dear Concern
I connected the CMSDK timer example with the Cortex - M0 processor. I have written exception handler for a timer in assembly code. After a certain moment interrupt is generated from the timer module in CMSDK. I see that the processor enters the exception handler for the first time and executes the handler and stays there. Please check the timer handler which basically sends a digit to a peripheral when triggered. The code is provided below. The processor does not return to the reset handler from the timer handler. I see that the processor when enters the timer handler for the first time responds to the interrupt and in the end of executing the timer handler provides the address like fffffff8. fffffff8,..fffffffc.....fffffffc...00000004 then gets stuck. The processor does not provide the other addresses. As a result, it does not go to reset handler hence does not respond to any peripherals. I am sharing the timer handler and reset handlers. Please help.
Reset_Handler PROC GLOBAL Reset_Handler ENTRY ; Setting the NVIC register LDR R1, =0xE000E400 ;Interrupt Priority Register LDR R0, =0x00000000 ;Priority: IRQ0: 0x00 STR R0, [R1] LDR R1, =0xE000E100 ;Interrupt Set Enable Register LDR R0, =0x00000001 ;Enable interrupt for timer STR R0, [R1] MOVS R0,#0x0; clearing the Primask to accept the interrupts MSR PRIMASK, R0 ; configure the timer LDR R1, =0x40001008 ;reload value to Timer MOVS R0, #0xFF STR R0, [R1] LDR R1, =0x40001000 ;control register value to Timer MOVS R0, #0x09 STR R0, [R1] ; apb led LDR R1, =0x40000000 ;Write to APB-LED with value with 0x25 MOVS R0, #0x35 STR R0, [R1] LDR R1, =0x20000000 ;Write to SRAM with value with 0x25 LDR R0, =0x25 STR R0, [R1] ; loop to keep processor awake so that it can receive interrupts AGAIN B AGAIN ENDP ;Timer_Handler Timer_Handler PROC EXPORT Timer_Handler LDR R1, =0x4000100C ;Clear Register MOVS R0, #0x01 STR R0, [R1] LDR R1, =0x40000000 ;Write to APB-LED with value with 0x25 MOVS R0, #0x25 STR R0, [R1] BX LR ENDP ALIGN 4 ; Align to a word boundary END