In my excitement of getting first movement on my machine last night.

In my excitement of getting first movement on my machine last night. I did something to break chilipepper or the JSON server. (It occurred as I was tweaking TinyG settings.

MAC OS.10.12.2
JSON 1.92
FTDIUSB serial Driver 2.3

I can talk to the tinyG using cool term.
$ & $$ returns appropriate text.

within Chillpeppr I can connect to the SPJS - within the serial port console I only see the following.


commands seem to buffer at the SPJS and not get through to the board.

Im wondering whether or not I inadvertantly changed a board configuration wrt communication settings. (I recall I was tweaking the max jerksetting and set one of them to zero when this first occurred)Here are the comm setting I got out of coolterm.

[ej] enable json mode 0 [0=text,1=JSON]
[jv] json verbosity 4 [0=silent,1=footer,2=messages,3=configs,4=linenum,5=verbose]
[js] json serialize style 1 [0=relaxed,1=strict]
[tv] text verbosity 1 [0=silent,1=verbose]
[qv] queue report verbosity 1 [0=off,1=single,2=triple]
[sv] status report verbosity 1 [0=off,1=filtered,2=verbose]
[si] status interval 250 ms
[ec] expand LF to CRLF on TX 0 [0=off,1=on]
[ee] enable echo 0 [0=off,1=on]
[ex] enable flow control 1 [0=off,1=XON/XOFF, 2=RTS/CTS]
[baud] USB baud rate 5 [1=9600,2=19200,3=38400,4=57600,5=115200,6=230400]

Hopefully Ive just done something dumb

You probably have the serial port still open in cool term so spjs can’t open it

Ah, that was it, i think I was also neglecting to restart SPJS. Thanks - problem resolved. (I did do something Dumb!!)

BTW, I now run SPJS with the -v all the time just to look at what it thinks is going on. I’ve had no more task usage run crazy and run the nodemcu at 115200 with no problems.

@Steve_Anken great that’s a good tip Steve. No sooner had I shut town cool term and thought it was aok, it stopped working again. Inexplicably

So after more experimenting I retraced my steps and as mentioned I did set $xjm=0. X Jerk Maximum to zero. This does send the TinyGv8 into a bit of a loop and blocks JSON communication. When I set it back to 20 million the board returned back to normal and worked fine again.

I repeated the process and set $xjm =0 and found that to was quite reproduceable -

Why was I motivated to do this you ask… it is because the clear path servos I am using have their own mass reaction tuning capability to determine setting such as jerk, and I dont want to have multiple jerk compensations conflicting with one another. I post this on the TinyG forum.

Feel free to reproduce this if you wish but you will have to reinstate the setting using coolterm

Our just try default buffer in spjs widget as that makes ChiliPeppr act like cool term. What if you use jerk of 1 or 10 or something so low it almost doesn’t exist?

@jlauer oh I’ll give that a try, and yeah I’ll try setting a low but not zero value.