It has been a very good week - lots of progress and I'm feeling a little proud of myself... until last night.
I managed to let the smoke out of an L293 driver chip, but the fire was quickly subdued and I was sure that the damage was localized (the curtain is easily replaced and I'm sure the hair will grow back), This, now, seems not to be the case (the localized damage part - I am still certain about the hair).
I first realized I had a problem while programming an 16F88... The little stepper motor I'd been working with just wouldn't go. At first I thought I'd somehow mistyped, but much checking and I determined that a couple of ports wouldn't work. Clearly I'd done more damage than I thought. A new 16f88 and... no joy. Uh oh.
So, next I tried the [bottom of page] code on a 12F683. This works... only partially. The LED on GPIO.2 flashes as expected, but not GPIO.0 or GPIO.1 - in any configuration (that is, with or without any other port "plugged in" similarly). I went back to the 16F88 - with another chip, similar "blink LED" type program and, results are similarly inconsistent. Sometimes plugging in one port or another, one LED may blink, but always wrongly. That is, PORTA or B some LEDs blink as expected, others not at all.
I removed from ICSP and mounted chips directly in the programmer, in case some capacitance or supernatural thing was affecting my result; not that I can determine. Always the program cycle completes, the chip may be read, EEPROM values are stored properly and fuse bits seem to be set and saved, but... always there is some inconsistency in the operation of the ports.
At this point, with the number of chips that are failed and the number of configurations tried (I do not list all), I can think of nothing else it might be other than the U2 programmer. I must admit however, that it seems unlikely that every detail (including the power/ programming LED indicator) would appear to function, but leave inconsistent results in such a way. Or is it?
Oh, and yes... the power supply is solid 5V and filtered as it has been all the while everything worked so well.
First, I suspect it is wise to verify my test program (below). This will, I believe, blink GPIO 0, 1, and 2 at approximately 1 Hz, yes? Second, is anyone familiar enough with U2 (or know of documents) that I might use to troubleshoot the function of the programmer? Last, can anyone think of some possible issue I have not addressed?
Code:OSCCON = %01110000 '8 MEG INTERNAL DEFINE OSC 8 ' TELL EVERYBODY TRISIO = 0 ' OUTPUT ONLY ANSEL = 0 ' DIGITAL MAIN: GPIO.0 = 1 GPIO.1 = 1 GPIO.2 = 1 Pause 500 ' Delay for .5 seconds GPIO.0 = 0 GPIO.1 = 0 GPIO.2 = 0 Pause 500 ' Delay for .5 seconds Goto MAIN End
Bookmarks