ATMEGA32U2-MUR Atmel, ATMEGA32U2-MUR Datasheet - Page 189

• Manufacturer Part Number: ATMEGA32U2-MUR
• Description: MCU AVR 32K FLASH 16MHZ 32VQFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA32U2-MUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Data Converters: -

20.3.3
20.4
20.4.1
20.4.2
7799D–AVR–11/10
General Operating Modes
Design guidelines
Introduction
Power-on and reset
The following design guidelines should be met:
In addition it is highly recommended to connect a 10µF capacitor to the VBUS line
The USB controller is disabled and reset after a hardware reset generated by:
In the case of USB End Of Reset (EOR), the USB controller is reset, but not disabled. Therefore
the device remains attached.
Figure 20-7 on page 189
Figure 20-7. USB controller states after reset
• Serial resistors on USB Data lines must have 22 Ohms value (
• Traces from the input USB receptacle (or from the cable connection in the case of a tethered
• Voltage transient / ESD suppressors may also be used to prevent USB pads to be damaged
• U
device) to the USB microcontroller pads should be as short as possible, and follow differential
traces routing rules (same length, as near as possible and avoid vias accumulation).
by external disturbances.
cap
– Power on reset
– External reset
– Watchdog reset
– Brown out reset
– debugWIRE reset
– USB End Of Reset
capacitor should be 1µF (
Clock stopped
FRZCLK = 1
(macro off)
USBE = 1
Device
illustrates the USB controller main states on power-on:
+/-
10%) for correct operation.
USBE = 0
Reset
HW RESET
(from EOR)
ATmega8U2/16U2/32U2
USBE = 0
USBE = 0
+/-
(except from EOR)
Any other
5%).
HW RESET
state
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