Datasheet

PIC16C62X
DS30235J-page 60  2003 Microchip Technology Inc.
9.9 Code Protection
If the code protection bit(s) have not been
programmed, the on-chip program memory can be
read out for verification purposes.
9.10 ID Locations
Four memory locations (2000h-2003h) are designated
as ID locations where the user can store checksum or
other code identification numbers. These locations are
not accessible during normal execution, but are
readable and writable during Program/Verify. Only the
Least Significant 4 bits of the ID locations are used.
9.11 In-Circuit Serial Programming™
The PIC16C62X microcontrollers 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 customers to manufacture boards
with unprogrammed devices and then program the
microcontroller just before shipping the product. This
also allows the most recent firmware or a custom
firmware to be programmed.
The device is placed into a Program/Verify mode by
holding the RB6 and RB7 pins low, while raising the
MCLR
(VPP) pin from VIL to VIHH (see programming
specification). RB6 becomes the programming clock
and RB7 becomes the programming data. Both RB6
and RB7 are Schmitt Trigger inputs in this mode.
After RESET, to place the device into Programming/
Verify mode, the program counter (PC) is at location
00h. 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
PIC16C6X/7X/9XX Programming Specification
(DS30228).
A typical In-Circuit Serial Programming connection is
shown in Figure 9-19.
FIGURE 9-19: TYPICAL IN-CIRCUIT
SERIAL PROGRAMMING
CONNECTION
Note: Microchip does not recommend code
protecting windowed devices.
External
Connector
Signals
To Normal
Connections
To Normal
Connections
PIC16C62X
V
DD
VSS
MCLR/VPP
RB6
RB7
+5V
0V
V
PP
CLK
Data I/O
V
DD