9.3.2 Power-On Reset (POR)

A POR circuit ensures the device is reset from power-on. The POR circuit is active until VDD crosses the VPOR threshold.

A power-on event generates an internal POR pulse when a VDD rise is detected above VPOR. The device supply voltage characteristics must meet the specified starting voltage and rise rate requirements to generate the POR pulse. In particular, VDD must fall below VPOR before a new POR is initiated. For more information on the VPOR and VDD rise-rate specifications, refer to the “Electrical Characteristics” chapter. A POR event can also be generated when the 1.1 V core voltage drops below a safe operating condition.

The POR bit in the Reset Control (RCON[0]) register is set to indicate the POR.

Note: When the device exits the Reset condition (begins normal operation), the device operating parameters (voltage, frequency, temperature, etc.) must be within their operating ranges; otherwise, the device will not function correctly. The user software must ensure that the delay between the time power is first applied and the time the system Reset is released is adequate to get all operating parameters within the specification.