OK. Thanks. I received the file. I'm a newbie, so i'm asking the following questions:
What is the FOX port used by the servo kernel module ? How can I enable the fast timer API ? Thanks in advance for your help. Best regards, Giovanni Ernst Mayerhofer <[EMAIL PROTECTED]> wrote: Hi, No i didn't forget the attachments, they were deleted. here you are: http://files.the-signs.com/servo.tar.gz 2007/2/3, Giovanni <[EMAIL PROTECTED]>: > > Dear Ernst, > > thanks for your reply. However I didn't find any file attached to your > message. Maybe forgotten ? > > Best regards, > Giovanni > > Ernst Mayerhofer <[EMAIL PROTECTED]<ernst.mayerhofer%40gmail.com>> > wrote: if you want to make something which works really well, you have to do > it in > > the kernel ;-) > > I made a kernel module once. As I modified it now for you and didn't test > it > on the foxboard, there might be a problem, so feel free to ask me if there > is some problem. > > just compile the servo.c attached with the also attached makefile. you > have > to change the path of AXIS_TOP_DIR in the Makefile. > > once you have compiled it, transfer it to the foxboard and type: > $ insmod servo.o > if you want to see the kernel log messages, type > $ dmesg > then you can make a new device node , eg > $ mknod c /etc/servo c 249 0 > and, if you want to set the servo to a specific position, write the value > of > T_on in us to /etc/servo: > $ echo 500 > /etc/servo > > it should work! > notice that if you want to use it, you have to enable the fast timer api. > > greets and pardon for my bad english, > > ernst mayerhofer > > 2007/2/2, Giovanni <[EMAIL PROTECTED] <pino_otto%40yahoo.com>>: > > > > This solution sounds cool. > > > > Did you try it with a real case ? > > > > I would like to run some real working code based on this idea. If you > have > > some code ready to run, can you post it ? Otherwise we can collaborate > to > > develop some working code and test it. > > > > Best regards, > > Giovanni > > > > spargelzack <[EMAIL PROTECTED] <spargelzack%40yahoo.com><spargelzack% > 40yahoo.com>> wrote: > > (sorry if this shows up twice, i'm not familiar with the yahoo groups > > > > interface yet) > > > > Hi Everybody > > > > I found a cheap + fast solution for using servos with the foxboard. > > > > First, there is a way to use the i/o lines not described on the > > acmesystems website (it's well known on the axis developer website > > though). You can use write() on Ports A+B after proper initialization. > > > > The Clock interval is around 5 us, so you have to pass about 4000 > > values for a full 2ms period. > > > > But as i found out, the 20ms interval isn't all that important. What > > matters is the length of the pulse. > > > > So, here's my code: > > > > -- > > #include <stdio.h> > > #include "stdlib.h" > > #include "unistd.h" > > #include "sys/ioctl.h" > > #include "fcntl.h" > > #include <sys/time.h> > > #include <asm/etraxgpio.h> > > > > int main(int argc, char **argv){ > > int fd; > > int i; > > int pos; > > unsigned char mask; > > unsigned char period[4000]; > > > > if(argc > 1) > > pos = atoi(argv[1]); > > else > > pos = 100; > > > > // better use memset() here, but this is proof-of-concept code > > for(i=0; i<pos+1; i++){ > > if(pos > i) > > period[i] = 0xFF; > > else > > period[i] = 0; > > } > > > > fd = open("/dev/gpiob", O_RDWR); > > > > if(!fd){ > > printf("open error\n"); > > exit(-1); > > } > > > > mask = 1<<6 | 1<<7; // use pins PB6 and PB7 according to the > > fox pinout > > > > // prepare for write() > > if(ioctl(fd, _IO(ETRAXGPIO_IOCTYPE, IO_CFG_WRITE_MODE), > > IO_CFG_WRITE_MODE_VALUE(1, mask, 1<<1))){ > > perror("ioctl error"); > > exit(-1); > > } > > > > for(;;){ > > write(fd, &period, pos+1); // write the pulse, > > followed by a zero to set the output > > usleep(5000); // let the CPU breathe a bit.. > > } > > } > > -- > > > > This only works with ports A and B, not with the G line. > > > > Supply any value between 100 and 400 as first argument to set the > > position of two servos connected to PB6 and PB7. > > > > example: > > > > ./motor 180 > > > > This uses LESS THAN 1% CPU when running. > > > > This is proof of concept code, so it's UGLY AND NOT USEFUL OUT OF THE > > BOX. Also, my english sucks a bit. > > > > --- In [email protected] > > <foxboard%40yahoogroups.com><foxboard%40yahoogr > oups.com>, "zooltheno1" > > <[EMAIL PROTECTED]> wrote: > > > > > > Hi > > > I want to use RC-Servos with the Foxboard, the normal interfall is > > > 1-2ms and 20ms pause. > > > I tried to use udelay for the delay, put the minimum is 40ms, > > > which is far to slow, even normal AC is faster. > > > How could I get the nesasery delay without 100% CPU load ? > > > > > > Bye > > > Ralph > > > > > > > > > > > > > > > ------------------------------------------------ > > Resources are limited, Imagination is unlimited. > > > > --------------------------------- > > Want to start your own business? Learn how on Yahoo! Small Business. > > > > [Non-text portions of this message have been removed] > > > > > > > > [Non-text portions of this message have been removed] > > > > > > ------------------------------------------------ > Resources are limited, Imagination is unlimited. > > --------------------------------- > Everyone is raving about the all-new Yahoo! Mail beta. > > [Non-text portions of this message have been removed] > > > [Non-text portions of this message have been removed] ------------------------------------------------ Resources are limited, Imagination is unlimited. --------------------------------- Don't pick lemons. See all the new 2007 cars at Yahoo! Autos. [Non-text portions of this message have been removed]
