My friend gave me a stepper, bipolar rated at 5.3V 8.5ohm (0.625A / phase)
I use AVR + ST L6219 for controller http://www.st.com/stonline/products/...re/ds/1377.pdf
I have 0.22ohm 1w resistor then set vref to 1.65v since the formula from datasheet to calculate max current is
I max = Vref /RS * 10
= 1.65 / 0.22 * 10
= 0.75A -> a little bit over current
then I measure the voltage at RS, it 0.12v
= 0.12 / 0.22
Am I on the right track here?
Is it normal for 0.625A stepper drived by 0.75A controller drain 0.64A ?
Thank you for your comment & advice.
I'll change vref to 1.375v.
since there is no problem I'll rebuild the circuit from breadboard to pcb.