Hi All,
After I have struggled for few days on settings interrupts, I thought I
should share this with you. I would also appreciate it if you would
correct me if I am wrong. Here's how I did it in plain language: Coding
is in RED
1. Globally disable all interrupts
CSR &= ~1; // global disable
IER = 0 ; // reset IER (This is not in the apps note but I thought
no harm doing this)
2. Enable NIME. This is very important to ensure that your
interrupt run after you globally enable all.
IER |= 0x00000002; //enable NMIE
3. Map your vector table ( IST ) to a base address. I put it in my
DDR RAM. Not sure if this is suitable but it works for me. This is the
part where I am stuck the longest.
I miss interpret the apps notes thinking that I should set with the bit
0 to 10 of the address(last 4 hex add). Actually it's the first 5 hex
address. You can refer to your .MAP file to see where is your vector
table map to. The following table I got it from the SPRU732d Chapter 5.
ISTP = 0x80000000; //set ISTP to base add 80000 XXX ( this is to
actually set bit 10th to 31th )
Here's is how I declare in linker command
Under memory
DDVec: o = 0x80000000 l = 0x00000200
Under sections
"vectors" : load = DDVec, run = vecs
Here's how I do in the in vectors.asm. I am not sure why the apps notes
said that putting 8 NOPs is sufficient enough. I understand that the ISR
need to be done in 8 instruction. But putting 8 NOPs is not even 32
bytes. So I added a few NOPs to make it 32 bytes.
.ref _c_int00
.ref _ MYINTERRUPT ; refer the address of ISR
defined in C program
.sect "vectors"
RESET_RST:
MVKL .S2 _c_int00, B0
MVKH .S2 _c_int00, B0
B .S2 B0
.loop 9
NOP
.endloop
NMI_RST:
.loop 6
NOP
.endloop
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
RESV1:
.loop 6
NOP
.endloop
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
RESV2:
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
.loop 6
NOP
.endloop
INT4:
.loop 6
NOP
.endloop
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
INT5:
MVKL .S2 _MYINTERRUPT, B0
MVKH .S2 _ MYINTERRUPT, B0
B .S2 B0
.loop 9
NOP
.endloop
INT6:
.loop 6
NOP
.endloop
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
INT7:
.loop 6
NOP
.endloop
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
INT8:
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
.loop 6
NOP
.endloop
INT9: NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
.loop 6
NOP
.endloop
INT10: NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
.loop 6
NOP
.endloop
INT11: NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
.loop 6
NOP
.endloop
INT12: NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
.loop 6
NOP
.endloop
INT13:
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
.loop 6
NOP
.endloop
INT14:
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
.loop 6
NOP
.endloop
INT15:
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
.loop 6
NOP
.endloop
Here's how my .MAP file look like
vectors 0 80000000 00000200 RUN ADDR = 00000000
80000000 00000200
vectors.obj (vectors)
4. Clear the interrupt event with EVTCLRx
INTC_EVTCLR2 &= ~(1 << 13);
5. Map the event to a interrupt with INTMUXx
INTC_INTMUX1 |= (77 << 8); //refer to the event mapping table in TRM for
event ID
6. Enable the event with IER
IER |= (1 << 5); //enable interrupt event. I'm using interrupt no 5
7. Finally, Globally enable all interrupt
CSR |= 3; //global enable,GIE, PGIE
Hope this help. Do correct me if I'm wrong or if there is better way to
write. Thanks.
Regards,
Suzanne Lim
