Microchip Technology PICkit 2, User Manual

Page: 26 / 53

PICkit™ 2 and ICSP™
©
2006 Microchip Technology Inc. DS51553B-page 21
3.4 V
DD
During ICSP programming, the PICmicro MCU needs to be powered in accordance
with the device specification. Typically, the PICmicro MCU supply voltage is connected
to the application circuit supply voltage. The application circuit can be powered by the
PICkit 2 Microcontroller Programmer or externally. There are a few precautions that
need to be observed.
3.4.1 The application circuit is powered by the PICkit 2
Microcontroller Programmer.
The PICkit 2 Microcontroller Programmer supply voltage (V
DD
) is +5V. If the application
circuit operates at a different voltage, isolation circuitry may be required so that the two
voltage levels do not conflict.
3.4.2 The application circuit is powered externally.
The PICkit 2 Microcontroller Programmer supply voltage (V
DD
) is +5V. If the application
circuit operates at a different voltage, isolation circuitry may be required so that the two
voltage levels do not conflict.
3.4.3 Bulk Erase is used.
Some PICmicro MCU devices use a bulk erase function to erase program memory,
data EEPROM memory, ID locations, and Configuration bits. Typically, the bulk erase
function requires a supply voltage (V
DD
) of 4.5 to 5.5 Volts (refer to the device
programming specification for device specific requirements).
This voltage range can be a problem if the application circuit is designed to operate at
a different supply voltage range. In order to bulk erase the PICmicro MCU, the
application circuit needs to take into consideration the bulk erase voltage requirement
while protecting any voltage sensitive circuitry.
CAUTION
The PICkit 2 Microcontroller Programmer supply voltage (V
DD
) is +5V.
CAUTION
The USB port current limit is set to 100 mA. If the target plus PICkit 2 Microcontroller
Programmer exceeds this current limit, the USB port will turn off. The target may be
powered externally if more power is required.
CAUTION
The PICkit 2 Microcontroller Programmer supply voltage (V
DD
) is +5V.