ATMEGA16U2-16AU Atmel, ATMEGA16U2-16AU Datasheet - Page 185

• Manufacturer Part Number: ATMEGA16U2-16AU
• Description: 8-bit Microcontrollers - MCU 16K Flash
• Manufacturer: Atmel

Specifications of ATMEGA16U2-16AU

• Product Category: 8-bit Microcontrollers - MCU
• Rohs: yes
• Core: AVR
• Data Bus Width: 8 bit
• Program Memory Size: 16 KB
• Data Ram Size: 1.25 KB
• Data Rom Size: 512 B
• Program Memory Type: Flash
• Factory Pack Quantity: 1250

20. USB Controller
20.1
20.2
7799D–AVR–11/10
Features
Overview
•
•
•
The USB controller provides the hardware to implement a USB2.0 compliant Full-Speed USB
device in the ATmega8U2/16U2/32U2. A simplified block diagram of the USB controller is shown
in
The USB controller requires a 48 MHz ±0.25% reference clock for USB Full-Speed compliance.
This clock is generated by an internal PLL. The reference clock to the PLL must be provided
from an external crystal or an external clock input. Only these two clock options will be able to
provide a reference clock within the accuracy and jitter requirements of the USB specification.
S e e s e c t i o n
ATmega8U2/16U2/32U2 system clock and clock options.
To comply to the USB specifications electrical characteristics, the USB Pads (D+ or D-) must be
powered at 3.0V to 3.6V. As the ATmega8U2/16U2/32U2 can be powered up to 5.5V, an inter-
nal regulator is provided to correctly power the USB pads. See
on page 186
Figure 20-1. USB controller Block Diagram
USB 2.0 Full-speed device
Ping-pong mode (dual bank), with transparent switch
176 bytes of DPRAM
Figure 20-1 on page
– 1 endpoint of 64 bytes max (default control endpoint)
– 2 endpoints of 64 bytes max (one bank)
– 2 endpoints of 64 bytes max (one or two banks)
for details on the powering options available for the USB controller
“ S y s t e m C l o c k a n d C l o c k O p t i o n s ” o n p a g e 2 6
UCAP
D-
D+
185.
Recovery
Regulator
DPLL
Clock
UVCC
Interface
USB
clk
48MHz
ATmega8U2/16U2/32U2
PLL
6x
clk
8MHz
“USB Module Powering Options”
USB DPRAM
PLL clock
Prescaler
On-Chip
XTAL1
CPU
f o r d e t a i l s o n t h e
185