Problems with SW_MODE bit in CONFIG register

Posted on July 01, 2014 at 01:11

I'd like to enable the HardStop interrupt (i.e. SW_MODE = 0) when I home my motor and then disable it afterward so that subsequent moves do not trigger the interrupt.  Enabling the interrupt before I start homing via GoUntil and ReleaseSW work fine.  I checked the STATUS and CONFIG registers to confirm that there aren't any fault conditions, and that the SW_MODE bit is cleared when I send my command to enable the hardstop interrupt.

Following any call to GoUntil or ReleaseSW, my command to set SW_MODE fails every time.  I get a NOTPERF_CMD error flag in the STATUS register and as expected, the SW_MODE bit is not set.

So far, the only way I can set SW_MODE is *after* I use any HiZ command that disables the bridges.  However, this is not what I want because the axis will drop when the bridges are disabled!

What is strange is that after homing, and after some unknown period of time, I can send a command to set SW_MODE and it doesn't result in a NOTPERF_CMD flag.

Can anyone recommend strategies for determining why I'm getting NOTPERF_CMD immediately after GoUntil or ReleaseSW?

#notperf_cmd #l6470 #sw_mode