problem when Writing to GPIOs through Macro

Adel

Hello everyone.

I’m using Control card TMS320F2803x Piccolo, I want to set some switches in my application.

At the beginning I use specific way to close the switches together witch worked perfectly, I just write to GPADAT register.

GpioDataRegs.GPADAT.bit.GPIO16 = 1;

GpioDataRegs.GPADAT.bit.GPIO18 = 1;

GpioDataRegs.GPADAT.bit.GPIO26 = 1;

--------------------------

I try to define the GPIOs in Macro :

#define OPEN_SWITCH1_COMMAND (GpioDataRegs.GPADAT.bit.GPIO16 = 0)
#define CLOSE_SWITCH1_COMMAND (GpioDataRegs.GPADAT.bit.GPIO16 = 1)

#define OPEN_SWITCH2_COMMAND (GpioDataRegs.GPADAT.bit.GPIO26 = 0)
#define CLOSE_SWITCH2_COMMAND (GpioDataRegs.GPADAT.bit.GPIO26 = 1)

#define OPEN_SWITCH3_COMMAND (GpioDataRegs.GPADAT.bit.GPIO18 = 0)
#define CLOSE_SWITCH3_COMMAND (GpioDataRegs.GPADAT.bit.GPIO18 = 1)

And I try to close the switches like it look below:

CLOSE_SWITCH1_COMMAND;

CLOSE_SWITCH2_COMMAND;

CLOSE_SWITCH3_COMMAND;

It doesn’t work, the GPADAT register doesn’t updated.

but if I adding above 5 nops after every command like it look below :

CLOSE_SWITCH1_COMMAND;

NOP;NOP;NOP;NOP;NOP;

CLOSE_SWITCH2_COMMAND;

NOP;NOP;NOP;NOP;NOP;

CLOSE_SWITCH3_COMMAND;

It works rightly.

Can someone tell me the reason why it happened ?

Best Regards

Adel

over 15 years ago

0 quark over 15 years ago

Expert 2220 points

Have you tried looking into the assembly code generated by the compiler? It should give you a clue what was different.

Use the "-k" (Keep Generated .asm Files) compiler option to generate the assembly code.

0 Eggi over 15 years ago in reply to quark

Prodigy 235 points

Hi,

i don't know much about piccolo controller, but on my f2812 i have to set and clear ios like this

#define SET GpioDataRegs.GPASET.bit.GPIOA15 = 1;
#define CLEAR GpioDataRegs.GPACLEAR.bit.GPIOA15 = 1;

The data reg has no effect to the pin, you just can use it to read the actual state of the pin

Regards

Eggi

0 Adel over 15 years ago in reply to Eggi

Prodigy 135 points

i try this option but it doesn't work.

Best Regards

Adel

0 Mitja Nemec over 15 years ago

Genius 5885 points

Hi Adel

It is a pipeline issue mentioned somewhere in the manuals. For this reason TI added CLEAR and SET registers as Eggi pointed out.

Regards, Mitja

0 Lori Heustess over 15 years ago in reply to Mitja Nemec

TI__Guru* 93800 points

Please see this information on the GPIO frequently asked questions wiki page:

http://processors.wiki.ti.com/index.php/General_Purpose_IO_%28GPIO%29_FAQ_for_C2000#Q:_Back-to-back_DAT_register_writes_do_not_work_as_expected

-Lori

C2000™︎ microcontrollers

C2000 microcontrollers forum

problem when Writing to GPIOs through Macro