Working fine on the 16F628A
In my design I upgraded the power stage to an ULN2068 (1.5A max per output) and put an embedded FTDI usb to USART chip. All on a 100x50mm single sided PCB (I'll share the PCB as a sign of gratitude once I finish debugging it a little on the usb part).
Also i'm planning to put a safety stop serial command with another pic sniffing the serial commands, because if you make a mistake on the instruction it will execute completly before you regain control of the motor, and that on my aplication is critical.
I got a problem anyhow but i don't know if it's software related or from my "squeeze pcb components to the max to reduce pcb size" techniques.
Works fine on a half an full step mode, but on microstepping sometimes works and sometimes starts making a strange noise on the coils making them hum and jitter untill I reset the whole driver. It's probable that the pic or the gates gets a little dizzy from emi noise because all kinds of lab equipments are connected to the same line so i'm working on that.
One doubt i had is if driving the stepper motor by limiting to a fixed current won't reduce torque in half step modes? (2 coils at 50% current vs 1 coil at 100% current)
Then why is better to drive them this way?. I know constant curent means that is aproximately constant in torque independant of the coils activated, but wouldn't be better with full current on every coil at expense of more current?
Last edited by El_AMPo; - 22nd November 2010 at 18:00.
"If at first doesn't work, kicking it wont help either"
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