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« on: December 29, 2015, 01:04:25 AM »
Hi Ben,
Thanks for helping!! I found the firmware zip in the library. Very nice work of firmware coding!!!
- I always use arduino sdk to load the program into arduino board. Just want to learn, how can you load the firmware into attiny841. what kind of the software and what kind of cable need to be used to load the firmware into attiny841? any good link for learning that?
- For pwm, for example, I set the MaxPwm to 255 and use 3.7V for VM. when I use motor.setMotor(1, 125), I assume that the driver output should be around 1.85V. But when use mulimeter to measure it, it is actually 3.0V. is it possible that the motor driver drv8837 itself does not provide linear output.
- Also, when I set motor.setMotor(1, 255), max driver output only 3.2V out of 3.7V. I wonder if drv8837 has high resistant of mosfet which eat up some voltage. Here are two observation.
1) Connect driver 2 output pins to motor, max is 3.2V
2) Since my motor only drive in one direction, I connect Vbatt (3.7) directly to motor(+)pin while connect only one driver output pin(low) to motor(-), now max can archive ~3.5V. It concludes that drive8837 internal each mosfet might eat up around 0.25-0.3V.