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EasyPIC6 Development System
MikroElektronika
page
There are two ways of programming PIC microcontrollers: Low Voltage and High Voltage programming modes. The
3,&ÀDVK
programmer uses
solely High Voltage programming mode during its operation. This mode requires voltage higher than the microcontroller’s power supply voltage
(the range between 8V to 14V, depending on the type of the microcontroller in use) to be brought to the MCLR/Vpp pin in order so that the
process of programming/debugging may be performed.
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mode is enabled, the programming process is initiated by applying a logic one (1) to the PGM pin. Unlike this mode, the High Voltage programming
mode is always enabled and the programming process starts by applying a high voltage to the MCLR/Vpp pin.
All PIC microcontrollers have the Low Voltage programming mode enabled by default. In some rare cases, in order to enable the microcontroller
to be programmed in the High Voltage programming mode, it is necessary to apply a logic zero (0) to the PGM pin, which prevents the
microcontroller from entering the Low Voltage programming mode. Depending on the microcontroller in use, it is possible to select one of the
following pins RB3, RB4 and RB5 to be used as the PGM pin. Jumper J10 is used as the PGM pin selector as shown in Figure 3-3.
Jumper J10 position
when the PGM line
is connected to the
RB3 pin.
Jumper J10 position
when the PGM line is
connected to the RB4
pin.
Jumper J10 position
when the PGM line
is connected to the
RB5 pin.
Jumper J10 default position
when RB3, RB4 and RB5
pins are not connected to
the PGM line.
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Various positions of jumper J10
Jumpers J8 and J9 are used for selecting the socket to receive the
programming signal. Figure 3-5 shows the position of jumpers J8
and J9 depending on DIP sockets in use.
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The position of jumpers J8 and J9
Microcontroler is plugged
into one of the following
sockets: DIP40, DIP28
DIP18A or DIP18B.
(Default position)
Microcontroller is plugged
into one of the following
sockets: DIP20, DIP14 or
DIP8.
The function of the MCLR (Master Clear) pin depends on the position
of jumper J7. When placed in the left-hand position, the MCLR pin
has default function, i.e. is used as MCLR/Vpp. Otherwise, when the
jumper is placed in the right-hand position, the MCLR pin is available
as an I/O pin.
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The position of jumper J7
MCLR used as an
I/O pin.
MCLR used as the
MCLR/Vpp pin.
MCU-PGD
Multiplexer
PGD
PROG
USB
VCC
D+
GND
D-
Build-in
with mikroICD
programmer
MCU-PGC
PGC
MCLR
Programming lines
User interface
MCLR
R
R
R
DATA
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Programmer schematic
During programming, a multiplexer disconnects
the microcontroller pins used for programming
from the rest of the board and connects them to
the
3,&ÀDVK
programmer. After the programming
is complete, these pins are disconnected from the
programmer and may be used as input/output
pins.
