No speed information provided

[Max-stahlke]

i use the DDSM210 motor with the DDSM Driver hat (a). If i send the command "{"T": 10010, "id": 3, "cmd": 1000, "act": 5}" via the UART ESP32 port i get a response "{"T":20010,"id":3,"typ":210,"spd":-1,"crt":-1,"act":5,"tep":29,"err":0}", where the "spd" field is always "-1". However, the speed is correctly applied to the motor. How can i get the information about the velocity of the motor? I also tried to talk to the motors directly. I was able to rotate them in the correct speed but i did not get a correct anwser.

[ak2tx]

Ran into this exact same thing - DDSM Driver HAT (A), DDSM210 motors, spd/crt always -1 no matter what, err:0, temp readings look normal. Did some digging since I need real velocity feedback for odometry on a mobile robot, here's what I found in case it helps anyone.

First thing I checked: is this actually a bad/misread frame, or is the motor really sending -1? Turns out it's not a framing issue - when the CRC actually fails on this firmware, it sends a very different, degraded packet: {"T":20010,"crc":0}, nothing else in it. I could reliably trigger that by interleaving CMD_DDSM_INFO with continuous drive commands. But the normal -1 packets look like a totally valid reply: {"T":20010,"id":1,"typ":210,"spd":-1,"crt":-1,"tep":29,"err":0} - right id, right type, temperature moves around sensibly as the motor warms up, err 0. That's a passing CRC-8 with an otherwise-sane payload, thousands of times in a row. So the frame is being read correctly, the motor itself is putting -1 in there.

Also tried adding a small delay between the left/right motor commands in case the two motors' replies were stepping on each other on the bus - no change. And tried both mode 2 (speed loop) and mode 3 (position loop) - same -1 behavior either way (mode 3 also cooked one of my wheels to an overtemp fault under continuous streamed commands, unrelated but worth a warning for anyone testing that).

Since you mentioned in your post that you tried talking to the motor directly and still got nothing back, and now that I've ruled out a framing bug on my end too, this feels like it's coming from the DDSM210's own firmware rather than anything on the HAT/ESP32 side. Anyone know if there's a firmware version thing going on, or a mode/command that actually populates this? Kind of stuck without real feedback for closed-loop odometry.