PIC12C672 MICROCHIP [Microchip Technology], PIC12C672 Datasheet - Page 40

• Manufacturer Part Number: PIC12C672
• Description: 8-Pin, 8-Bit CMOS Microcontroller with EEPROM Data Memory
• Manufacturer: MICROCHIP [Microchip Technology]

PIC12CE5XX
8.12
The PIC12CE5XX microcontrollers program memory
can be serially programmed while in the end applica-
tion 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 GP1 and GP0 pins low while raising the
MCLR (V
specification). GP1 becomes the programming clock
and GP0 becomes the programming data. Both GP1
and GP0 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 pro-
gram 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 PIC12CE5XX Programming Specifications in the
In-Circuit Serial Programming Guide.
A typical in-circuit serial programming connection is
shown in Figure 8-15.
DS40172A-page 40
In-Circuit Serial Programming™
PP
) pin from V
IL
to V
IHH
(see programming
Preliminary
FIGURE 8-15: TYPICAL IN-CIRCUIT SERIAL
External
Connector
Signals
Data I/O
CLK
+5V
V
0V
PP
PROGRAMMING
CONNECTION
To Normal
Connections
To Normal
Connections
1997 Microchip Technology Inc.
V
V
MCLR/V
GP1
GP0
V
DD
SS
DD
PIC12CE5XX
PP