Prop losing all I/O's
TC
Posts: 1,019
Hello all,
I was reading on another post, that Parallax has a lifetime warranty. So I think I am going to take them up on the offer.
But I have a question.
At the time (about 3 months ago) I had a parallel display hooked to the Prop,(P14..P27), I had no protection resistors on the data lines(dummy), and I let it run overnight. When I went to bed the display was working like it should, but when I got up in the morning, there was nothing on the display. I checked all the obvious things (3.3V, 5V, GND), they were good. I went to the I/O's, I used my high tech data line tester(led & resister) to see if there was anything happening. And there wasn't.
So I removed the display, made it so the prop was the only thing alive, and I loaded a object that makes all the I/O's high, then after 500ms, takes them low, then repeats. And again, took my high tech data tester and checked all the outputs. All but P28..P31did not work. And just to check I was doing things right, I swapped that Prop with a good Prop, loaded the same object, and all the I/O's worked(except the 3 that I screwed up on).
So my question is, What could of made all the I/O's quit working? including the ones where there was nothing hooked to them?
Thanks
TC
I was reading on another post, that Parallax has a lifetime warranty. So I think I am going to take them up on the offer.
But I have a question.
At the time (about 3 months ago) I had a parallel display hooked to the Prop,(P14..P27), I had no protection resistors on the data lines(dummy), and I let it run overnight. When I went to bed the display was working like it should, but when I got up in the morning, there was nothing on the display. I checked all the obvious things (3.3V, 5V, GND), they were good. I went to the I/O's, I used my high tech data line tester(led & resister) to see if there was anything happening. And there wasn't.
So I removed the display, made it so the prop was the only thing alive, and I loaded a object that makes all the I/O's high, then after 500ms, takes them low, then repeats. And again, took my high tech data tester and checked all the outputs. All but P28..P31did not work. And just to check I was doing things right, I swapped that Prop with a good Prop, loaded the same object, and all the I/O's worked(except the 3 that I screwed up on).
So my question is, What could of made all the I/O's quit working? including the ones where there was nothing hooked to them?
Thanks
TC
Comments
Which display was that because I can't see how you would have 14 I/O connected? Since you ran this without resistors (and reading from the display I guess) I can only assume you have waived all right to ethically claim any kind of a warranty. Anyway as you know an IC is constructed on a common substrate and isolation between devices on the common substrate is mainly by means of semiconductor junctions. Damaging a device in a group can damage the underlying substrate and junctions thereby affecting devices in the vicinity. An IC is after all an integrated circuit, not a bunch of discrete ones.
I figured that. And I don't really think I would've tried. I was just saying. plus at $8 a chip it is not worth sending it in, waiting, getting it back.
The display is a crystalfontz 256x128 graphic display. at the time I was only using it as a character display, then I was going to work on the graphic part. Here is the datasheet. As you can see on page 7 there are 13(not 14) pins that can be used. I was going to tie RESET to Vdd at a later date.