Datasheet

 2010-2012 Microchip Technology Inc. DS41419D-page 335
PIC16(L)F1824/1828
28.0 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
In Program/Verify mode the Program Memory, User IDs
and the Configuration Words are programmed through
serial communications. The ICSPDAT pin is a bidirec-
tional I/O used for transferring the serial data and the
ICSPCLK pin is the clock input. For more information on
ICSP™ refer to the “PIC16F/LF182X/PIC12F/LF1822
Memory Programming Specification” (DS41390).
28.1 High-Voltage Programming Entry
Mode
The device is placed into High-Voltage Programming
Entry mode by holding the ICSPCLK and ICSPDAT
pins low then raising the voltage on MCLR/VPP to VIHH.
Some programmers produce V
PP greater than VIHH
(9.0V), an external circuit is required to limit the VPP
voltage. See Figure 28-1 for example circuit.
FIGURE 28-1: VPP LIMITER EXAMPLE CIRCUIT
VREF
VPP
VDD
VSS
ICSP_DATA
ICSP_CLOCK
NC
RJ11-6PIN
RJ11-6PIN
R1
270 Ohm
To MPLA B
®
ICD 2
To Targ et Bo ar d
1
2
3
4
5
61
2
3
4
5
6
R2 R3
10k 1% 24k 1%
U1
LM431BCMX
A
2
3
6
7
8
A
A
A
K
NC
NC
1
4
5
Note: The MPLAB ICD 2 produces a VPP volt-
age greater than the maximum V
PP spec-
ification of the PIC16F/LF1824/1828.