Datasheet

 2008-2011 Microchip Technology Inc. DS41364E-page 361
PIC16(L)F1934/6/7
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 “PIC16193X/PIC16LF193X Memory
Programming Specification” (DS41360).
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 M P L AB
®
ICD 2
To Targe t Bo ard
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
voltage greater than the maximum VPP
specification of the PIC16(L)F1934/6/7.