Member Since: September 13, 2011

Country: United States

  • Thanks for the great sale! I've placed a bunch of orders for items at work, but this is my first personal order. Can't wait to get started on some projects and introduce my kids to it. Thanks again!

  • I've been using this breakout for about a year now and it's been working pretty well. I've noticed from the beginning, that I need to have a delay of about 25 ms after I send serial data before I can bring the RTS line low otherwise the transmission gets corrupted or is not transmitted. This hasn't been a big issue yet, but for a recent project I am running two 485 lines from one Arduino Mega 2560. I am receiving commands on one 485 line from the host software and transmitting them if the address is correct (I have several Megas running). I am expecting a response on the second 485 line from the devices I am sending commands to. The issue is that the peripheral devices respond in ~20ms and sometimes I get it and sometimes I don't (based on the state of the RTS pin). I need to transmit these responses back to the host software.

    I feel like I should need these delays in the program. I would assume that the arduino has completed the transmission before it moves on from a serial.write() command. Any ideas?

  • I've been using this motor driver for a few months now and love it. I originally bought the evaluation driver and communications kit from ST Microelectronics and then decided to try my hand at writing my own library. I am running it with the ATXMEGA128A1 @ 3.3V and it works great. If you can't communicate with it, make sure that you drive the STBY pin high (it took me a while to figure this out). Another issue I ran into was that there seems to be a lag in the busy signal.

    I use the commands:

    while (!(PORTF.IN & PIN3_bm));



    I wait ~20µs between when the busy signal goes high (signalling an end of move) to when I can send the next command, I'm not sure why this is.

    I haven't had any thermal issues unless I try to over drive the motors by increasing the duty cycles for KVAL_ACCEL, KVAL_DECEL, KVAL_RUN. To get more torque I just went to a bigger motor. To figure out your motor parameters download the dspin software from ST Micro and use the BEMF calculator.

    My one complaint is that the spacing of the pins is not uniform. I ended up directly solding wires to the board, but it would be nice to have connectors on it. Maybe SparkFun can offer compatible connectors in the related products? Other than that, this is a great product and the 128 µ-stepping is really smooth and really quiet. It is great to have this driver handle all of the pulsing and calculations. Simply tell it speeds, directions, accelerations, etc. and it does the rest!

No public wish lists :(