38.2 Low-Voltage Programming Entry Mode

The Low-Voltage Programming Entry mode allows the PIC® Flash MCUs to be programmed using VDD only, without high voltage. When the LVP bit of the Configuration Word 4 register is set to ‘1’, the low-voltage ICSP programming entry is enabled. To disable the Low-Voltage ICSP mode, the LVP bit must be programmed to ‘0’.

Entry into the Low-Voltage Programming Entry mode requires the following steps:

  1. MCLR is brought to VIL.
  2. A 32-bit key sequence is presented on ICSPDAT, while clocking ICSPCLK.

Once the key sequence is complete, MCLR must be held at VIL for as long as Program/Verify mode is to be maintained.

If low-voltage programming is enabled (LVP = 1), the MCLR Reset function is automatically enabled and cannot be disabled. See the “MCLR” section for more information.

The LVP bit can only be reprogrammed to ‘0’ by using the High-Voltage Programming mode.