1.

Overview

1.1

Programming Data Flow

Nonvolatile Memory (NVM) programming data can be supplied by either the high-voltage In-Circuit Serial

programmed into the Program Flash Memory (PFM), Data EEPROM Memory, dedicated “User ID” locations and the

Configuration Bytes.

1.2

Pin Utilization

Five pins are needed for ICSP programming. The pins are listed in the table below. For pin locations and packaging

information, refer to the table in 6. APPENDIX B.

Table 1-1. PIN DESCRIPTIONS DURING PROGRAMMING

Pin Name

During Programming

Function

Pin Type

Pin Description

ISCPCLK

ICSPCLK

I

Clock Input - Schmitt

Trigger Input

ISCPDAT

ICSPDAT

I/O

Data Input/Output - Schmitt

Trigger Input

Program/Verify mode

Program Mode Select

P

Power Supply

P

Ground

Legend: I = Input, O = Output, P = Power

Note: 

1.

The programming high voltage is internally generated. To activate the Program/Verify mode, high voltage

needs to be applied to the MCLR input. Since the MCLR is used for a level source, MCLR does not draw any

significant current.

1.3

Hardware Requirements

1.3.1

High-Voltage ICSP Programming

1.3.2

Low-Voltage ICSP Programming

operating voltage.

1.3.2.1

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

available and can be used to program the device.

PIC18FXXQ41

Overview

Programming Specification

DS40002143B-page 4