Datasheet

 2010-2013 Microchip Technology Inc. DS40001430E-page 169
PIC16(L)F720/721
20.0 IN-CIRCUIT SERIAL
PROGRAMMING™ (ICSP™)
ICSP™ programming allows customers to manufacture
circuit boards with unprogrammed devices. Programming
can be done after the assembly process, allowing the
device to be programmed with the most recent firmware
or a custom firmware. Five pins are needed for ICSP™
programming:
• ICSPCLK
• ICSPDAT
•MCLR
/VPP
•VDD
•VSS
The device is placed into Program/Verify mode by
holding the ICSPCLK and ICSPDAT pins low then
raising the voltage on MCLR/VPP from 0V to VPP. In
Program/Verify mode the program memory, user IDs and
the Configuration Words are programmed through serial
communications. The ICSPDAT pin is a bidirectional I/O
used for transferring the serial data and the ISCPCLK pin
is the clock input. For more information on ICSP™ refer
to the “PIC16F72x/PIC16LF72x Programming
Specification” (DS41332).
FIGURE 20-1: TYPICAL CONNECTION FOR ICSP™ PROGRAMMING
VDD
VPP
GND
External
Device to be
Data
Clock
VDD
MCLR/VPP
VSS
ICSPDAT
ICSPCLK
*
*
*
To Normal Connections
*
Isolation devices (as required).
10k
Programming
Signals
Programmed
VDD