Follow the instructions here if you aren’t set up for git. This page was last edited on 31 May , at Embedded Linux Class by Mark A. Retrieved from ” https: I couldn’t set them during kernel boot with the 2. The standard way to interface with the outside world in Linux is through Kernel Drivers.
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There are two ways to do this, eurpwm slick way which may not work and the sure way. A given pin can have one from as many as eight lines assigned to it. What’s the highest frequency you can get?
Here’s another PWM lead.
platform/amx/ti/drivers/ehrpwm.c – kernel/lk – Git at Google
If these command cause the SSH connection to close, you may have to get a newer version of Angstrom. You may have to set the duty cycle to 0 to change the frequency. In this exercise you will learn how to use the Beagle’s pulse width modulation pwm hardware using the sysfs interface and also learn about pin multiplexing pin mux on the way. I was able to get a 1. Stick a scope on the pin and see if the frequency and duty cycle are right. The DM has 11 general purpose timers, 4 of which gpt8-gpt11 can be brought fhrpwm of the chip and used for pulse width modulation DM TRM page The u-boot details are here.
Can you guess why? In a previous exercise EBC Exercise 11 gpio Polling and Interrupts you saw how linnux use the gpio to produce a square wave out using a C program and sysfs. Navigation menu Personal tools Log in Request account. This will show up at ehrpwm1A the 0 maps to A.
The standard way to interface with the outside world in Linux is through Kernel Drivers.
There are some pins that you can control what they output. How do you know which one to change?
Try changing the frequency and duty cycle. Embedded Linux Class by Mark A. This page was last edited on 31 Mayat We want pin 6. The version of the kernel and u-boot that I’ve given you should already be configured to access the PWM pins. If it isn’t you’ll have to recompile the Kernel and u-boot.
EBC Exercise 13 Pulse Width Modulation 3.2
This says the MUX is presently set on pin 7. Retrieved from ” https: I couldn’t set them during kernel boot with the 2.
Views Read View source View history. Counting starts on the left with 0. Now, check the settings by browsing to http: This is for the 3. You could even do PWM from a shell command by using devmem2 to write to the memory mapped registers from a command line. Currently there are no standard PWM whrpwm for the Beagle, though a couple have been proposed  and .