Part Number:DRV8873
Hello there,
I have made a breakout board fot the DRV8873S in order to control a DC motor in PH/EN mode. I have coded a PD-position regulator for the project and now i need to read a current. According to the information in the datasheet i have calculated an appropriate Rsense: maximum current in 3.5Amps, so Rsense = 1100 * 5V / 3.5A = 1571 Ohm. The Vpropi is output from 10 pin on the picture.
Here comes the problem. As a microcontroller i am using Atmega 328p (Arduino UNO), which has 10-bit ADC. But I am getting 82/98 out of 1023 from the ADC, even if i try hard to revolute motors shaft. I feel the great resistance on the shaft since i have a regulator, but the current, red by ADC doesn't change. Am i doing something wrong?
Best regards, Nikita
UPD:
I have made some tests: had connected multimeter in series with +7.4V to driver, when i applied presure on the motors shaft the current raised up to 1Amps. I tried to measure Vpropi, but it is less than 3mV with the same test conditions. What is wrong?
Here is my layout:
