The address is in bytes and pinconf is an array of integers, which are 4 bytes long.
j. On Wed, Apr 2, 2014 at 8:02 AM, milkyway <[email protected]> wrote: > I am new to beagle baord. I have a doubt here. Please help. > > In the following line > > pinconf[0x217c/4] = pinconf[0x217c/4] & 0x0000ffff | 0x00040000; // > gpio_149 > > Why do you need the division inside the pinconf array for indexing? > > > On Wednesday, 7 December 2011 20:26:08 UTC+5:30, dl4mea wrote: >> >> Hello, >> >> My self given task was to get a LED blinking on the Beagleboard. >> >> After getting bored from "echo 0 > brightness" and puzzling together >> some pieces of code that I found on the net, I finally got a piece of >> plain C code that I can cross compile on a Linux machine and play on >> the Beagleboard. The two user LEDs as well as one pin of the extension >> connect flash in a 1sec clock with it. >> >> No guarantee for completeness, no guarantee for functionality, but >> here it works. >> >> Enjoy! >> >> Günter (dl4mea) >> >> /* Blinking of user LEDs USR0 and USR1 and gpio_157 on Expansion >> Connector P2 >> NOTE: gpio_157 is 1.8V IO, possibly not sufficient for a LED >> >> disconnect user LEDs from Linux >> echo none > /sys/class/leds/beagleboard::usr0/trigger; echo none > / >> sys/class/leds/beagleboard::usr1/trigger; >> >> compile using >> <path_to_cross>/arm-armv6-linux-gnueabi-g++ -static blink.c -o blink >> >> References: OMAP35x Applications Processor, Technical Reference Manual >> spruf98u.pdf >> */ >> >> #include <stdio.h> >> #include <stdlib.h> >> #include <sys/types.h> >> #include <sys/stat.h> >> #include <unistd.h> >> #include <fcntl.h> >> #include <sys/mman.h> >> >> int main(void) >> { >> >> printf ("open file descriptor for PADCONFIG\n"); >> int fd = open("/dev/mem", O_RDWR | O_SYNC); //O_SYNC makes the >> memory uncacheable >> if (fd < 0) { >> printf("Could not open PADCONFIG memory fd\n"); >> return 0; >> } >> >> // Pad configuration >> printf ("map PINCONFIG\n"); >> volatile ulong *pinconf; >> pinconf = (ulong*) mmap(NULL, 0x10000, PROT_READ | PROT_WRITE, >> MAP_SHARED, fd, 0x48000000); >> if (pinconf == MAP_FAILED) { >> printf("Pinconf Mapping failed\n"); >> close(fd); >> return 0; >> } >> >> printf ("set pinconfig GPIO\n"); >> pinconf[0x217c/4] = pinconf[0x217c/4] & 0x0000ffff | >> 0x00040000; // gpio_149 >> pinconf[0x2180/4] = pinconf[0x2180/4] & 0xffff0000 | >> 0x00000004; // gpio_150 >> pinconf[0x218c/4] = pinconf[0x218c/4] & 0x0000ffff | >> 0x00040000; // gpio_157 >> close(fd); >> >> /* -------------------------------------- */ >> >> printf ("open file descriptor for GPIO\n"); >> int gpio_fd = open("/dev/mem", O_RDWR | O_SYNC); >> if (gpio_fd < 0) { >> printf("Could not open GPIO memory fd\n"); >> return 0; >> } >> >> // GPIO configuration >> printf ("map GPIO\n"); >> volatile ulong *gpio; >> gpio = (ulong*) mmap(NULL, 0x10000, PROT_READ | PROT_WRITE, >> MAP_SHARED, gpio_fd, 0x49050000); >> if (gpio == MAP_FAILED) { >> printf ("GPIO Mapping failed\n"); >> close(gpio_fd); >> return 0; >> } >> >> printf ("set GPIO config\n"); >> >> // Configure GPIO pins on bank 5 as output. >> // GPIO 5 is at physical address 0x49056000 = 0x49050000+0x6000 >> gpio[0x6034/4] &= ~0x20600000; // set low for output >> // Also disable the wakeupenable and irqenable intertupts >> // GPIO clear_Wakeupenable is offset by 0x80 for each bank >> gpio[0x6080/4] = 0x20600000; // 0x1: Clear the corresponding >> bit in the GPIO_WAKEUPENABLE register >> // GPIO clear_irqenable1 is offset by 0x60 for each bank >> gpio[0x6060/4] = 0x20600000; // 0x1: Clear the corresponding >> bit in the GPIO_IRQENABLE1 register >> // GPIO clear_irqenable2 is offset by 0x70 for each bank >> gpio[0x6070/4] = 0x20600000; // 0x1: Clear the corresponding >> bit in the GPIO_IRQENABLE2 register >> >> /* -------------------------------------- */ >> >> printf ("Toggle Pins\n"); >> >> int j=0; >> for (j=0; j<10; j++) >> { >> printf ("j=%u\n", j); >> //clear_data_out has offset 0x90 >> gpio[0x6090/4]=0x20600000; >> usleep(500000); >> //set_data_out has offset 0x94 >> gpio[0x6094/4]=0x20600000; >> usleep(500000); >> } >> >> close(gpio_fd); >> } > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. -- Given a choice between two theories, take the one which is funnier -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
