Quote:
Originally Posted by mmatej
Yup, maybe delays are bad. But what are that ticks? Tomorrow I'll try to connect it to speakers with amplifier to check if there are more voices. Somebody should probably connect the Kindle to the oscilloscope to check that too.
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Noise on the accessory port is probably caused by voltage fluctuations due to varying load during wifi or 3G transmission (which draws a lot of power), during eink updates, and during other power-hungry events. For PWM output that could be clipped with a resistor and a pair of back-to-back diodes (or LEDs). The ticks might actually be your output. You can time how fast your code runs to see if it matches the tick rate. Like I said, it can take a long time to return from the echo statements, depending on how the device driver handles that sysfs (proc) interface to the accessory port.