Datasheet

Table Of Contents
PIC12F519
DS41319B-page 48 © 2008 Microchip Technology Inc.
8.9 Program Verification/Code
Protection
If the code protection bits have not been programmed,
the on-chip program and data memory can be read out
for verification purposes.
The first 64 locations and the last location (OSCCAL)
can be read, regardless of the setting of the program
memory’s code protection bit. If the code protect bit
specific to the FLASH data memory is programmed,
then none of the contents of this memory region can be
verified externally.
8.10 ID Locations
Four memory locations are designated as ID locations
where users can store checksum or other code
identification numbers. These locations are not
accessible during normal execution, but are readable
and writable during program/verify.
Use only the lower 4 bits of the ID locations. The upper
bits should be programmed as 0s.
8.11 In-Circuit Serial Programming™
The PIC12F519 device can be serially programmed
while in the end application circuit. This is simply done
with two lines for clock and data, and three other lines
for power, ground and the programming voltage. This
allows users to manufacture boards with
unprogrammed PIC12F519 device and then program
the PIC12F519 device just before shipping the product.
This also allows the most recent firmware, or a custom
firmware, to be programmed.
The PIC12F519 device is placed into a Program/Verify
mode by holding the GP1 and GP0 pins low while
raising the MCLR
(VPP) pin from VIL to VIHH (see
programming specification). The GP1 pin becomes the
programming clock, and the GP0 pin becomes the
programming data. Both GP1 and GP0 pins are Schmitt
Trigger inputs in this mode.
After Reset, a 6-bit command is then supplied to the
device. Depending on the command, 14 bits of program
data are then supplied to or from the device, depending
if the command was a Load or a Read. For complete
details of serial programming, please refer to the
PIC12F519 Memory Programming Specification,”
(DS41316).
A typical In-Circuit Serial Programming connection is
shown in Figure 8-12.
FIGURE 8-12: TYPICAL IN-CIRCUIT
SERIAL PROGRAMMING
CONNECTION
External
Connector
Signals
To N o rm al
Connections
To N o rm al
Connections
PIC12F519
V
DD
VSS
MCLR/VPP
GP1/ICSPCLK
GP0/ICSPDAT
+5V
0V
V
PP
CLK
Data
V
DD