PIC18F2455-I/SP Microchip Technology Inc., PIC18F2455-I/SP Datasheet - Page 131

• Manufacturer Part Number: PIC18F2455-I/SP
• Description: Microcontroller; 24 KB Flash; 2048 RAM; 256 EEPROM; 24 I/O; 28-Pin-SPDIP
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F2455-I/SP

• A/d Inputs: 10-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 12 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 23
• Interface: I2C/SPI/USART/USB
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SPDIP
• Programmable Memory: 24K Bytes
• Ram Size: 2K Bytes
• Speed: 48 MHz
• Timers: 1-8-bit, 3-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

14.0
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 14.9 “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.
14.1
The PIC18F2450/4450 device family contains a full-
speed and low-speed compatible USB Serial Interface
Engine (SIE) that allows fast communication between
FIGURE 14-1:
© 2006 Microchip Technology Inc.
USB Clock from the
Note 1: This signal is only available if the internal transceiver is disabled (UTRDIS = 1).
Oscillator Module
USB Control and
VREGEN
USB RAM
256-Byte
Configuration
UNIVERSAL SERIAL BUS
(USB)
Overview of the USB Peripheral
2: The pull-ups can be supplied either from the V
3: Do not enable the internal regulator when using an external 3.3V supply.
EN
3.3V Regulator
USB PERIPHERAL AND OPTIONS
PIC18F2450/4450 Family
UTRDIS
USB
SIE
FSEN
Transceiver
Advance Information
FS
OE
USB
pin or from an external 3.3V supply.
any USB host and the PIC
be interfaced directly to the USB, utilizing the internal
transceiver, or it can be connected through an external
transceiver. An internal 3.3V regulator is also available
to power the internal transceiver in 5V applications.
Some special hardware features have been included to
improve performance. Dual 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
endpoint memory usage within the USB RAM space.
Figure 14-1 presents a general overview of the USB
peripheral and its features.
PIC18F2450/4450
V
D+
D-
UOE
VM
VP
RCV
VMO
VPO
USB
(1)
(1)
Pull-ups
External
Speed)
(1)
(1)
(1)
(1)
(Full
(2)
Transceiver
External
®
microcontroller. The SIE can
Speed)
(Low
External 3.3V
Supply
DS39760A-page 129
(3)
USB Bus
USB Bus