so...continuing my AT89LP51ED2 bootloader saga -- I have the chip into bootloader mode now, and am able to send commands to the bootloader, however it rudely interrupts me in the middle of them with a checksum error
In git-blame, we usually see lines in a file like below:
f9a0a430 (Owen Lin 2011-08-17 22:07:43 +0800 1)
The first column is the sha1 which represents the commit of last modified.
But sometimes it looks like this:
^f9a0a43 (Owen Lin 2011-08-17 22:07:43 +0800 1)
What is t...
I'm not sure if this behavior is bizarre, but here's what's happening: it seems if I run git blame on a file, any lines in that file that are from the initial commit have a SHA with a leading caret (^), like this
^bb65026 (Brian Danielak 2012-10-27 19:11:54 -0700 1) hello, world!
bbcd4a96 (Bria...
I never took it off, it got ripped off when the antenna cable got loose and bumped into it... And putting the original back is, as said, beyond my skills
Hello everyone. I apologize for a brief question here rather than on the site, but I think most of what I would have to write in a full question is irrelevant to the actual subject. Has anyone experienced oscillation in a half-H-bridge for long on-durations? I'm using UCC27201 driver. The circuit works fine for shorter pulses but when they become >1ms or so there is wild oscillation in the latter part of the pulse. I guess this is an edge case, but it has me wondering what to look for.
@PlasmaHH I really would like some suggestions as to what may cause this in general. To spontaneously go from stable operation to oscillation in the middle of a pulse seems strange to me.
I should say that the bootstrap capacitor is more than big enough for that not to be the problem, unless gate leakage is much more than specified. But even if it is, the high-side V_GS looks fine.
@PlasmaHH in this case the onset is very rapid and depending on the MOSFETs used it can appear as short-lived, sharp dropouts instead of actual oscillation. Perhaps the driver is broken. I will try another and see if the problem goes away.
@Asmyldof okay, I see what you mean. I had misunderstood your question. During the oscillation I haven't closely examined V_GS because V_S is wildly varying. Before the oscillations start, there is no significant change in V_GS.
@Asmyldof I know. It charges and stays charged. Immediately before the oscillation begins there has been no significant change in V_GS since the beginning of the on-time.
@Asmyldof what struck me was the number of presumed Vcc pads: 226 an an equal number Vss. That is 450 pads just for power supply? Do these CPU's indeed have so many pins pads? Not counting actual signals ...
@Asmyldof yes, I appreciate that. I asked in here just in case someone had an idea what may cause this in an otherwise properly working circuit. Of course if I ask on the site then I will provide complete information. Actually I now wonder if C_oss increase with falling V_DS (due to bulk capacitance discharge) is causing a new resonance to appear. I will check this.
@PlasmaHH as it happens I'm not really concerned with long pulses anyway. This is really just a curiosity for me, so I could ignore it and there would be no problem in the application. Only pulse widths of less than 100ns are interesting in reality.
@OleksandrR. The same behaviour might be lurking as some edge case near the values you want to actually use that thing with... some unlucky combination of just-in-spec components and it goes whooo
@PlasmaHH yes, you're right. And, who knows, maybe I will be interested in longer pulses in the future. (I am a physicist, not EE. This is not to drive a motor or something but to perturb a plasma.)
@PlasmaHH you have something that makes your frequency of interest and a scope with enough bandwidth. You have loads more than most people when tuning their first 27MHz/35MHz/40MHz antenna
L || C = tuning, calculate what you think your L is, calculate the C you need, look at the signal, add a C of 10% and see it go up or down. Down = too much C, up = too little
Some cars, now have nonlinear speedometers. How can they achieve to get different spacing between some speed ranges?
I'm not sure if this behavior is bizarre, but here's what's happening: it seems if I run git blame on a file, any lines in that file that are from the initial commit have a SHA with a leading caret (^), like this
^bb65026 (Brian Danielak 2012-10-27 19:11:54 -0700 1) hello, world!
bbcd4a96 (Bria...
