I/O programming in asm

[a00178074]

Posted on October 25, 2005 at 02:18

I/O programming in asm

[a00178074]

Posted on October 19, 2005 at 21:29

Hello!

I'm working with a ST72F324 MCU. I want to set a port like an output (PA4). When programming in C, I do the next:

PADDR=0xFF;

PAOR=0xFF;

PADR=0xFF;

and the led in this port is set, but when programming in asm, i do the next:

BSET PADDR,#4

BSET PAOR,#4

BSET PADR,#4

I hope with this code, the led on PA4 would be set but it doesn't.

Please, what is happening, I think i'm configuring correctly the I/O.

Thanks.

[fggnrc]

Posted on October 20, 2005 at 06:17

SSAM,

the ASM equivalent code of the C snippet is:

LD A,#$FF

LD PADDR,A

LD PAOR,A

LD PADR,A

What you wrote is different, because it touches only the bit #4, instead of all pins.

Are you sure that the led is attached to the right pin?

EtaPhi

[a00178074]

Posted on October 20, 2005 at 16:57

Thanks a lot, EtaPhi

I have done the same you wrote, my main program do the next:

.main

call port_init

loop

jra loop

.port_init

LD A,#$FF

LD PADDR,A

LD PAOR,A

LD PADR,A

ret

but running the program don't set the led in any PA port. When I use the similator it does'n set the PA ports anyway. The program is simple like this but i don't understand what is happenning. The ports are ok, because i probed them with the program in C.

I tried doing with a bit instruction bset,#4, after configuring like an output pin, but it didn't work.

I have to conect the MCU to a ST7538 and i need to generate REG_DATA AND RXTX signals from the MCU to the ST7538.The program i have is in assembler.

Could be something wrong in my workspace configuration?

[fggnrc]

Posted on October 21, 2005 at 05:13

It is very strange...

Since the C program code works, then the bug must lie in the asm source which is so simple...

By the way, which hardware definition file do you include?

I mean, the file which contains the definitions of HW ports i.e. PADR, PADDR and PAOR.

Replace PADR with $00, PADDR with $01 and PAOR with $02 (these are the common addresses for Port A registers, but check your datasheet) and see what happens.

You can also watch at the output of the C compiler.

After that, I have no more hint...

Bye

EtaPhi

[laurent239955_stm1]

Posted on October 24, 2005 at 07:11

You can generate a listing file (*.lst) by checking the option in the compiler. Then you can verify that the generated assembler code corresponds with yours.

Best regards

Laurent

[a00178074]

Posted on October 25, 2005 at 02:18

Hello!!

The problem was solved. The only thing i did was download the new version of the ST7VD and taking the program to the root c:\.

It is something i don't understand. Then with the ST7VD 3.1 the ports didn't work?

Could someone explain to me what was the problem with the ST7VD and the ports?

:(

Thank you again.

SSAM