Strange timing problem

Sam Gutkind

I just purchased the Propeller 40-pin DIP Education Kit, and have been following Lab #3 for setup and I/O pin testing.

All the pins I tested passed as outputs. Furthermore, pins 2 through 27 passed as inputs. But when I hooked my pushbutton circuit up to pin 1, the LED stopped flashing and stayed on. When I reloaded the program, it would stay off and never come on. Now I can't get it to flash again, on any of the pins.

The Fundamentals book suggested I try setting _clkmode to xtal1+pll8x. When I do this, the LED usually starts out staying solidly on. But when I press down on the crystal, it starts flashing extremely fast. I removed the crystal from the breadboard. Now, when I touch any piece of wire--sticking into the air, going absolutely nowhere--to the "XI" port, the oscillation rate slows down to about the intended speed. And it does slow down by a factor of 5 when I press the pushbutton. It slows down even more when my finger is pressed to the other end of this wire I attach to the "XI" port.

Any ideas about what's going on?

Sam Gutkind

Just to add one more thing--

I deleted the lines:

_clkmode = xtal1 + pll8x ' Feedback and PLL multiplier
_xinfreq = 5_000_000 ' External oscillator = 5 MHz

from the top of the program. Then everything ran as intended.

Kye

You may have been using improper timings. When I first stated using the propeller I tried using the

_clkfrq =·xinput + pll8x

_xinfreq = 10_000_00

Which is a big no no because of the xinput part. It should really have been xtal1 or xtal2.



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Nyamekye,