VRD311 datasheet(34/416 Pages) MICROCHIP

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DS30010118D-page 34

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2.7

Configuration of Analog and

Digital Pins During ICSP

Operations

If an ICSP compliant emulator is selected as a debugger,

it automatically initializes all of the A/D input pins (ANx)

as “digital” pins. This is done by clearing all bits in the

ANSx registers. Refer to Section 11.2 “Configuring

Analog Port Pins (ANSx)” for more specific information.

The bits in these registers that correspond to the A/D

pins that initialized the emulator must not be changed

by the user application firmware; otherwise,

communication errors will result between the debugger

and the device.

If your application needs to use certain A/D pins as

analog input pins during the debug session, the user

application must modify the appropriate bits during

initialization of the A/D module, as follows:

• Set the bits corresponding to the pin(s) to be

configured as analog. Do not change any other

bits, particularly those corresponding to the

PGCx/PGDx pair, at any time.

When a Microchip debugger/emulator is used as a

programmer, the user application firmware must

correctly configure the ANSx registers. Automatic

initialization of these registers is only done during

debugger operation. Failure to correctly configure the

analog input pins, resulting in the port value being read

as a logic ‘0’, which may affect user application

functionality.

2.8

Unused I/Os

Unused I/O pins should be configured as outputs and

driven to a logic low state. Alternatively, connect a 1 kΩ

to 10 kΩ resistor to VSS on unused pins and drive the

output to logic low.

VRD311 Datasheet(PDF) 34 Page - Microchip Technology