My English is unfortunately very poor (e.g., I don't even understand the word "impending" in this context) - can please someone try to explain in other words what the warning actually means and what kind of technical issues "can't long time use high level" are related to (current, voltage, percentage pwm, stalling, ....) ?
I also don't understand "impending" in that context.
I think the "can't long time use high level" is related to their spec that "This driver can operate at 0% -99% PWM modulation duty ratio". It is saying you should not drive the motors at 100% (high level) for too long, although they don't specify what a "long time" is.
el_supremo:
I also don't understand "impending" in that context.
I think the "can't long time use high level" is related to their spec that "This driver can operate at 0% -99% PWM modulation duty ratio". It is saying you should not drive the motors at 100% (high level) for too long, although they don't specify what a "long time" is.
That's exactly what it means.
This driver needs to be driven with a PWM signal only; you can't supply a steady HIGH state (ie - PWM=255) to it, because it likely uses an all N-channel MOSFET design, and needs the PWM switching states to keep the high-side boost circuit running properly. Otherwise, the high-side MOSFETs will stop conducting - I'm not sure if that will cause damage in some manner, it might.
Since they specify a 0-99% PWM rate - if you're using PWM of 0-255, then you would be limited to the values 0-252 (where 252 => 99% of max PWM on the Arduino).