The watchdog is one possible protection against unintentional motor activation or in case of system failure (e.g. SPI bus issues, microcontroller malfunction…), therefore it is recommended to keep it enabled. However it may be convenient to disable the WD during the development phase.
The following sequence disables the watchdog:
1. SPI Frame 1: Set the UNLOCK bit (GENCTRL1).
Important: While setting the UNLOCK bit, the WDTRIG bit must be inverted to avoid a wrong watchdog failure. The default value WDTRIG right after a power-on reset is 0.
2. SPI Frame 2: Set WDDIS (in GENCTRL2).
If a SPI frame is added between SPI Frame 1 and SPI Frame 2, then the UNLOCK bit is cleared. Consequently the WD stays enabled despite the SPI Frame 2.
This sequence requiring two consecutive SPI frames and involving two different registers, prevents a deactivation of the watchdog "by accident" with one single SPI command (e.g. due to a flipped bit).
