Datasheet

 2010 Microchip Technology Inc. Preliminary DS39964B-page 379
PIC18F47J53 FAMILY
23.0 UNIVERSAL SERIAL BUS
(USB)
This section describes the details of the USB peripheral.
Because of the very specific nature of the module,
knowledge of USB is expected. Some high-level USB
information is provided in Section 23.9 “Overview of
USB” only for application design reference. Designers
are encouraged to refer to the official specification
published by the USB Implementers Forum (USB-IF) for
the latest information. USB Specification Revision 2.0 is
the most current specification at the time of publication
of this document.
23.1 Overview of the USB Peripheral
PIC18F47J53 family devices contain a full-speed and
low-speed, compatible USB Serial Interface Engine
(SIE) that allows fast communication between any USB
host and the PIC
®
MCU. The SIE can be interfaced
directly to the USB, utilizing the internal transceiver.
Some special hardware features have been included to
improve performance. Dual access port memory in the
device’s data memory space (USB RAM) has been
supplied to share direct memory access between the
microcontroller core and the SIE. Buffer descriptors are
also provided, allowing users to freely program end-
point memory usage within the USB RAM space.
Figure 23-1 provides a general overview of the USB
peripheral and its features.
FIGURE 23-1: USB PERIPHERAL AND OPTIONS
3.8-Kbyte
USB RAM
USB
SIE
USB Control and
Transceiver
P
P
D+
D-
Internal Pull-ups
External 3.3V
Supply
FSEN
UPUEN
UTRDIS
USB Clock from the
Oscillator Module
Optional
External
Pull-ups
(1)
(Low
(Full
USB Bus
FS
Speed)
Speed)
Note 1: The internal pull-up resistors should be disabled (UPUEN = 0) if external pull-up resistors are used.
Configuration
VUSB
PIC18F47J53 Family