Single-Supply ICSP Programming

The device’s LVP Configuration bit enables single-supply (low-voltage) ICSP programming. The LVP bit defaults to a ‘1’ (enabled). The LVP bit may only be programmed to ‘0’ by entering the High-Voltage ICSP mode, where the MCLR/V_PP pin is raised to V_IHH. Once the LVP bit is programmed to a ‘0’, only the High-Voltage ICSP mode is available and can be used to program the device.

Important:

The High-Voltage ICSP mode is always available, regardless of the state of the LVP bit, by applying V_IHH to the MCLR/V_PP pin.
While in Low-Voltage ICSP mode, MCLR is always enabled regardless of the MCLRE bit. Also, the MCLR pin can no longer be used as a general purpose input.