l6470 Speed Register

[ivlasic]

Posted on April 15, 2013 at 14:25

According to Datasheet Reference:

In order to convert the SPEED value in step/s, the following formula can be used:

[step/s] = (SPEED X 2 –28)/ tick

That would mean that if I would like to work with step/seconds I have to multiply it like this (stepsPerSec * 67.10886) to get the real Value.

So if I run my Motor with 10 steps/sec for 60 Seconds at 128 Microsteps, the Motor have to make 76800 microsteps.

But if I get (read) a Position Register after 60 Seconds I am always getting bigger Value.

After try and error, I settled down to multiply my step/seconds with 65.9200 to get a 76800 steps.

Could it be that formula in Datasheet is wrong?

Greets, Igor

[Enrico Poli]

Posted on April 16, 2013 at 16:40

The mismatch is due by the fact that the tick duration is not exactly 250ns but depends on the internal clock frequency. Tolerances on the clock frequency affects the tick duration.

[ctyang]

Posted on July 14, 2016 at 10:10

How can I configure the chip to get a precise tick period? Can I use external clock as its clock source? I can't find control register to do so.

Regards,CT