TMS570LS3137: supply VCCAD before supplying VCC and VCCIO

Hi Sasaki,

Normally for device with separate power supplies for core and IO, the core is powered first, then IO. Hercules MCUs have built-in VMON module which handles the power sequence for Core and IO, so there is no requirement of power sequence for Vcc and Vccio. The VMON doesn't monitor Vccad, I recommend Vcc and Vccio first, then Vccad.