UART transmitting interrupt handler

You still haven't read the instructions for posting code, which makes any code you post look completely garbled...

Note that the vector table in itself is an array of addresses which may make it impossible to take an interrupt there. You are probably limited to putting breakpoints on the first instruction pointed at by the vector table entries.

You still haven't read the instructions for posting code, which makes any code you post look completely garbled...

Note that the vector table in itself is an array of addresses which may make it impossible to take an interrupt there. You are probably limited to putting breakpoints on the first instruction pointed at by the vector table entries.

sorry for bad code posting.
you are right that interrupt vector itself is an array of addresses but when it enters into IRQ mode it loads program counter by the starting address of IRQ routine.
which is LDR instruction.
I have placed breakpoints on that instructions.
So when it enters into IRQ mode it should load PC by IRQ routine starting address.
But it doesn't execute the instruction.
again i m posting the code where i placed the breakpoints in startup file

Vectors         LDR     PC,Reset_Addr
                LDR     PC,Undef_Addr
                LDR     PC,SWI_Addr
                LDR     PC,PAbt_Addr
                LDR     PC,DAbt_Addr
                ;DCD     ||Image$$ER_IROM1$$RO$$Length||+||Image$$RW_IRAM1$$RW$$Length||
                                DCD             0x4000 ;PHYTEC comment: This hard codes the size
                                                           ;that the secondary bootloader uses to copy
                                                           ;binary software to SDRAM.

                LDR     PC,IRQ_Addr
                LDR     PC,FIQ_Addr

And i placed breakpoints when CPSR is changed when it enters into IRQ mode and loads SP.

  Enter IRQ Mode and set its Stack Pointer
                MSR     CPSR_c, #Mode_IRQ:OR:I_Bit:OR:F_Bit
                MOV     SP, R0
                SUB     R0, R0, #IRQ_Stack_Size

i have placed breakpoints on all the points as shown in the code. but PC doesn't even enter in that code.

Does the address after LDR match the address of your IRQ handler as seen from the map file?

Have you tried to add breakpoints for all the other vectors?

HEY
when i place more than two break points in the program and try to run it. it executes code upto first break point but then the execution stops there. it doesnt go ahead by pressing F5. Even it doesnt go ahead if i press F10 or F11. Thats strange.
When i debug step by step using F11 it doesnt execute using F5.
I am doing onchip debugging and ETB module of LPC3180 supports upto two breakpoints at a time only.
So i dont reach on the exact address location where IRQ starting address is located.

Much can be done with only two breakpoints.

You may have to run the application multiple times, trying different locations for your breakpoints.

hey
i checked that whether my interrupt is routine is called from interrupt handler or not.
Its working. Interrupt handler defined in start up file calls function which i have defined in the source code.
I checked it by manually executing instruction at interrupt handler in startup file.
Now problem remains that when IRQ is generated does Program counter goes to interrupt handler defined in the start up file or not.
I am trying for this.

Hello

I run code from external SDRAM.
when IRQ is generated program counter jumps to some location in IRAM. i dont know how data is moved from external SDRAM to IRAM. So i cant come to know where my interrupt vector table is stored in IRAM.

it is exceedingly difficult to understand what's wrong without a clear understanding of HOW your system is organized. how does it boot? what is the logic behind the bootcode? memory available? without minimal topology details - I doubt whether anybody would be in a position to help. give more details in concise, technical language.

yeah sure.

My code is in external SDRAM which starts from 0x80000000.
In the starting of my code interrupt vector table is located then all functions are stored.
In my code i defined an IRQ handler function. Which should be called when IRQ is generated.
But When IRQ is generated it goes into onchip IRAM (0x00000000 to 0x00004000) instead of going into IRQ handler function.
I have verified that if program counter goes into interrupt vector table it calls the desired function.
So the problem is that when IRQ is generated why program counter doesnt enter into interrupt vector table.

in case of an IRQ, the processor is supposed to go to 0x18 - which must contain the instruction to just to your function. is that the case?

in meant, of course , "jump to your function"

no.
I have stored the whole code in SRAM. And the map file shows the location of IRQ handler function is 0x800001a4.
But it doesnt jump to the location 0x800001a4 when IRQ is generated. LPC3180 doesnt have vectored interrupt controller. It contains one main interrupt controller and two sub interrupt controller.

What happens when you single step past the code? do you get the registers bold in the window?

In simple step past memory is updated as it should be.
Even in single step everything goes well but when IRQ is generated program counter doesn't jump on IRQ routine while executing in single step.
keil doesnt offer simulation capabilities for lpc3180 so its a pain to check memory values everytime.

Hello

I managed to enter into the interrupt vector table when IRQ is generated.
I mapped IRAM to 0x00000000.
At startup interrupt vectors are located. But It doesn't jump to the desired location.
Instead of that if i execute LDR PC,[PC,#0x0018]
from external SRAM it jumps to the desired location but if i execute this instruction at the remapped location
0x00000018. It doesnt jump to the specific location.
Does anybody have any idea?

THANKS GUYS...
I MADE IT WORKING FINALLY..