Application using a MSP430G2553IRHB32. On/off power (VDD) is controlled directly by contacts of a rotary switch. When the switch goes into an 'off' position (power removed), VDD decays to the POR 1.6V threshold which disables the MCU to a low power state. System power goes from 2-6mA, to ~11uA. At this draw, the power supply caps don't discharge further. When the switch is rotated 'on', applying 3V back to VDD, the MCU will not start. There is a RC reset network 47K/2.2nF on /RST. The MCU will restart if VDD is first brought further below about 1.6V (hysteresis?) or if /RST is manually pulsed. Do I need a separate POR IC, or is there something else I can do using just the msp430g2553 ?
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