DM180021 Microchip Technology Inc., DM180021 Datasheet - Page 41

• Manufacturer Part Number: DM180021
• Description: MPLAB Starter Kit for PIC18F MCU
• Manufacturer: Microchip Technology Inc.

Specifications of DM180021

• Contents: MicroSD™ memory cardAcceleration sensorOLED display
• Lead Free Status / Rohs Status: RoHS Compliant part

B.4
© 2009 Microchip Technology Inc.
USB SUSPEND CURRENT LIMITATIONS FOR THE STARTER KIT
The USB specification limits devices to 2.5 mA of current draw from the bus while a
device is in a suspended state. This limit is tested during compliance testing for all USB
certified devices.
The design of the PIC18F Starter Kit utilizes an on-board debugger. To optimize the
starter kit for cost and available features, the debugger section provides the system
clock for both the debugger and the application portions of the circuit. As a result, the
debugger is always running, even when the debugger USB cable is not attached,
resulting in a current draw higher than allowed during USB suspend. In contrast, typical
applications will have their own clock sources and be able to better control their own
current consumption to meet the USB suspend specification. This can be achieved by
switching to a lower clock frequency or placing the microcontroller into Sleep mode,
among other possible methods.
USB Current Draw Requirements
DS51852A-page 37