create software for Altere PIO 's

[Altera_Forum]

this is my code below, 

its self explanatory, i am unable to get the IOWR_ALTERA_AVALON_PIO_SET_BITS(base) to work as the output is confirming it. My PIO is set to 1  # define ALT_MODULE_CLASS_GPIO_0 altera_avalon_pio # define GPIO_0_BIT_MODIFYING_OUTPUT_REGISTER 1    CODE:::  # include <stdio.h> # include <unistd.h> # include "altera_avalon_pio_regs.h" # include "system.h" # include <strings.h>  // Time in microseconds to wait for switch debounce  int main(void) {   printf("Simple\n"); // print a message to show that program is running  int data1 = 0x00000309;   int val,val2;  //while(1){    IOWR_ALTERA_AVALON_PIO_DATA(GPIO_0_BASE,data1);  val = IORD_ALTERA_AVALON_PIO_DATA(GPIO_0_BASE);  printf("previous value = %x \n",val);    IOWR_ALTERA_AVALON_PIO_SET_BITS(GPIO_0_BASE+4, 0x02);  val2 =IORD_ALTERA_AVALON_PIO_DATA(GPIO_0_BASE);  printf("value after setting the bit = %x " , val2); //} }  -----------------OUTPUT------------------   Simple previous value = 309  value after setting the bit = 309

[Altera_Forum]

You shouldn't call IOWR_ALTERA_AVALON_PIO_SET_BITS with an Offset, as the offset is already added inside the Macro.

[Altera_Forum]

Thanks for your help 

 I got this working    # include <stdio.h> # include <unistd.h> # include "altera_avalon_pio_regs.h" # include "system.h"    int main(void){  int val;   //IOWR_ALTERA_AVALON_PIO_DATA(GPIO_1_BASE,0x0000); //printf( " GPIO default values are set at 0 \n");   IOWR_ALTERA_AVALON_PIO_SET_BITS(GPIO_1_BASE,0x0003); val = IORD_ALTERA_AVALON_PIO_DATA(GPIO_1_BASE);  IOWR_ALTERA_AVALON_PIO_DATA(LEDR_BASE, val); usleep(10000000);   IOWR_ALTERA_AVALON_PIO_CLEAR_BITS(GPIO_1_BASE, 0x0001); val = IORD_ALTERA_AVALON_PIO_DATA(GPIO_1_BASE); IOWR_ALTERA_AVALON_PIO_DATA(LEDR_BASE, val);    //set latch //printf(" GPIO 1st bit set to 1\n");  // IOWR_ALTERA_AVALON_PIO_CLEAR_BITS(GPIO_0_BASE,0x1000);//oe enable  // IOWR_ALTERA_AVALON_PIO_CLEAR_BITS(GPIO_0_BASE,0x200);//clear latch    }

[Altera_Forum]

What's the advantage of using this approach instead of the IOWR_32DIRECT and IORD_32DIRECT? 

 (or just IOWR and IORD_

[Altera_Forum]

Readability.

[Altera_Forum]

Hmmm... IMHO any code that uses any of the IOWR* defines is inherently unreadable and difficult to maintain. 

In this case you are also forcing 3 io/memory cycles when (probably) 2 are needed. I'd also tend to recommend using 'write 1 to set' and 'write 1 to clear' registers for general pio in order to remove the need for read-modify-write cycles on shared resources (save the need to disable interrupts).

[Altera_Forum]

--- Quote Start ---  Readability.  --- Quote End ---     Nice comment!   Seriously can we have smaller, readable not-all capitals macros please.