Trouble with making delay with RPT Assembly command on 2808 proc

Franc Zajc

I need a short delay written in Assembly by repeating NOP command. I would like to do so with RPT command as described in : TMS320C28x CPU and Instruction Set Reference Guide (literature Nr. SPRU430E) on page 6-250.

I wrote following command lines;

RPT #10

|| NOP

CCS debugger does not recognise the " || NOP " as a valid command (text appear in green color, same as the comments). Why is that?

I also would like to know what " | | " stands for, because it is also not recognised and it shows up as green text.

Please advice how to do use RPT command correctly.

Thank you for answers

over 9 years ago

0 Vivek Singh over 9 years ago

TI__Guru** 115211 points

Hi Franc, This is correct instruction and I hope you are not getting any error while compiling this code. You can ignore the text color in CCS.

Regards,

Vivek Singh

0 Subrahmanya over 9 years ago in reply to Vivek Singh

TI__Mastermind 24095 points

Franc,

Are you using this inside a C code? You can try below.

__asm(" RPT #10 || NOP");

-Bharathi.

0 Franc Zajc over 9 years ago in reply to Subrahmanya

Prodigy 220 points

Dear,
thank you both for answers, I am using Assembly code, I am not familiar with C code.

The || NOP command not only that it shows in same text color as the comments, but after compiling there is no execution code for this line.

Assembly code :
RPT #10
||NOP
MOVZ DP,#SPIB_BASE>>6

Here is dissasembly line copied from CCS generated from code above: (something goes wrong at NOP command I am guessing)
112 RPT #10
00804a: F60A RPT #10
00804b: 7700 || NOP
115 MOVZ DP,#SPIB_BASE>>6
00804c: B9DD MOVZ DP, #0x1dd

Franc

0 Lori Heustess over 9 years ago in reply to Franc Zajc

TI__Guru* 91940 points

Franc Zajc said:
after compiling there is no execution code for this line.

The disassembly seems to be correct - at address 0x00804b there is 0x7700 which is a NOP. Does it not execute correctly?

Franc Zajc said:
00804a: F60A RPT #10
00804b: 7700 || NOP

0 Franc Zajc over 9 years ago in reply to Lori Heustess

Prodigy 220 points

Hello,
I am glad to hear dissasembly seems to be OK, but it doesn't work when executed.
I adjusted the RPT to 253 cycles(running at 60MHz, ecpected 4.22usec delay gap) and checked on the scope. I see only 3 cycles delay.It seems like the program skips the" || NOP "command.

Franc

0 Lori Heustess over 9 years ago in reply to Franc Zajc

TI__Guru* 91940 points

To be sure - are you "running" the code or single "stepping" the code?

0 Franc Zajc over 9 years ago in reply to Franc Zajc

Prodigy 220 points

****additional info****
I went trough the following program using step into (F5):
RPT #253
|| NOP
RPT #253
|| NOP
first it stopped on RPT #253 once, it skipped ||NOP, stopped on RPT #253 once and skipped ||NOP, and continued to next instruction.

0 Lori Heustess over 9 years ago in reply to Franc Zajc

TI__Guru* 91940 points

Please try running the code instead of single stepping. I suggest using a pin toggle around the code that you can measure on the 'scope.

0 Franc Zajc over 9 years ago in reply to Lori Heustess

Prodigy 220 points

Thank you Lori

I did both, I tried with single step and I also run the code with measuring on the scope.
Single step just skipped the instruction.
In run mode, scope showed SYSCLK/6 frequency of toggle pin.

Thanks

0 Vivek Singh over 9 years ago in reply to Lori Heustess

TI__Guru** 115211 points

Hi Franc, Is this issue resolved?

Regards,

Vivek Singh

0 Franc Zajc over 9 years ago in reply to Vivek Singh

Prodigy 220 points

Hi Vivek,

unfortunately I still have this problem, but I managed to circumvent the problem by using different commands. If you have a solution of how to use ˝||˝ in assembly, I would really appreciate it.

Thank you in advance and best regards,

Franc Zajc

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Trouble with making delay with RPT Assembly command on 2808 proc