There are two methods for externally powering the target:
In the following descriptions, only three lines are active and relevant to core debugger operation: pins 1 (Vpp/
MCLR), 5 (PGC), and 4 (PGD). Pins 2 (Vdd) and 3 (Vss) are shown on
Figure: Standard Connection To Target Circuitry for completeness.
When providing power to the target device, ensure that the target is not exposed to voltages higher than the device Vdd rating.
Absolute maximum ratings for the device Vdd must not be exceeded. Exposure to the maximum rating conditions for any length of time may affect device reliability.
Functional operation of the device at conditions above the parameters indicated in the device data sheets specification is not recommended.
See the device data sheet for required device voltage levels and maximum ratings.
Externally Powered through Target
The recommended method for powering the target device is an external power supply connected directly to the target board. In this configuration, target V
dd is sensed by the debugger to allow level translation for the target low-voltage operation. If the debugger does not sense voltage on its V
dd line (pin 2 of the interface connector), it will not operate.
Externally Powered through Debugger
An alternative method of powering the target device is an external power supply connected directly to the MPLAB ICD 4. Be aware that you must also select power from the MPLAB ICD 4 debugger via MPLAB X IDE.
Not all devices have the AVdd and AVss lines, but if they are present on the target device, all must be connected to the appropriate levels in order for the debugger to operate. They cannot be left floating.
In general, it is recommended that all Vdd/AVdd and Vss/AVss lines be connected to the appropriate levels. Also, devices with a Vcap line (PIC18FXXJ MCUs, for example) should be connected to the appropriate capacitor or level.
Note: |
The interconnection is very simple. Any problems experienced are often caused by other connections or components on these critical lines that interfere with the operation of the MPLAB ICD 4 In-Circuit Debugger system, as discussed in the following section. |
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