Sebastian, I am not sure what you mean by the FPGA register. Do you mean the interface register between the driver and the m5i20, or the register actually handling the PWM within the FPGA? As I said in an earlier email (off list), I concur that the value being sent to the FPGA through the interface register is correct (providing the bit shift to bits 16-27 is where the value is supposed to go), which would confirm that my pwmgen.scale is set to 1.0.
I was able to measure the duty cycle on a pain old multi-meter. At values of 0.125 and below, the voltage would start dropping from the almost 100% duty cycle voltage of just under 3.3V, and very linearly for the range of 0.125 down to 0.0. The voltage reading from my meter was in fact very accurate. Here are the voltage readings I got: Value Voltage >=0.126 3.278 0.125 3.272 0.120 3.144 0.110 2.884 0.100 2.623 0.090 2.362 0.080 2.102 0.070 1.841 0.060 1.580 0.050 1.320 0.040 1.059 0.030 0.798 0.020 0.538 0.010 0.278 Regards, Eric How are you measuring duty cycle? I'm confident that (at least in my test setup) setting pwmgen.XX.value causes the correct number to be set in the FPGA register. Take a look at <http://pastebin.ca/1208030>. I updated pwmgen.c to decode the number in the PWM Value Register, then used raw.dump-state to show the register when pwmgen.value was -1.0 to +0.3 in increments of 0.1. Lines 1-22 show the relevant dmesg output for .value=0, then I just show the PWM Value Register for the other .value settings. In addition to the correct numbers being set in the register, the corresponding LED on the 7i31 LED Debug board varies in intensity as expected, and the small DC servo (driven by a 7i30 servo amp) changes its speed as expected. I'm not sure why you're seeing what you're seeing. Is maybe your pwmgen.scale not set to 1.0? ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
