PIC16C662-20/TQ Microchip Technology, PIC16C662-20/TQ Datasheet - Page 71

• Manufacturer Part Number: PIC16C662-20/TQ
• Description: 8-Bit EPROM Microcontrollers with Analog Comparators
• Manufacturer: Microchip Technology

9.9
If
programmed, the on-chip program memory can be
read out for verification purposes.
9.10
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.
1996 Microchip Technology Inc.
Note:
the
Code Protection
ID Locations
code
Microchip does not recommend code
protecting windowed devices.
protection
bit(s)
have
not
been
Preliminary
PIC16C64X & PIC16C66X
9.11
The PIC16CXX 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 (V
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 Programming Specifications (Literature
#DS30228).
A typical in-circuit serial programming connection is
shown in Figure 9-20.
FIGURE 9-20: TYPICAL IN-CIRCUIT SERIAL
External
Connector
Signals
Data I/O
CLK
+5V
V
0V
In-Circuit Serial Programming
PP
PP
) pin from V
PROGRAMMING
CONNECTION
To Normal
Connections
To Normal
Connections
IL
to V
IHH
(see programming
DS30559A-page 71
V
V
MCLR/V
RB6
RB7
V
DD
SS
DD
PIC16CXX
PP