ATMEGA16U4-AU Atmel, ATMEGA16U4-AU Datasheet - Page 335

• Manufacturer Part Number: ATMEGA16U4-AU
• Description: MCU AVR 16K FLASH USB 44TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA16U4-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 26
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Processor Series: ATMEGA16x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 1.25 KB
• Interface Type: SPI, TWI, USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 26
• Number Of Timers: 5
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 12 Channel
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32ATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

27.5.3
7766F–AVR–11/10
External Hardware conditions
is programmed, the Reset Vector will always point to the Boot Loader Reset and the fuse can
only be changed through the serial or parallel programming interface.
Table 27-4.
Note:
The Hardware Boot Enable Fuse (HWBE) can be programmed (See
special hardware conditions under reset, the bootloader execution is forced after reset.
Table 27-5.
Note:
When the HWBE fuse is enable the ALE/HWB pin is configured as input during reset and sam-
pled during reset rising edge. When ALE/HWB pin is ‘0’ during reset rising edge, the reset vector
will be set as the Boot Loader Reset address and the Boot Loader will be executed (See Figures
27-3).
Figure 27-3. Boot Process Description
BOOTRST
HWBE
1
0
1
0
1. “1” means unprogrammed, “0” means programmed
1. “1” means unprogrammed, “0” means programmed
Boot Reset Fuse
Hardware Boot Enable Fuse
Reset Address
Reset Vector = Application Reset (address 0x0000)
Reset Vector = Boot Loader Reset (see
Reset Address
ALE/HWB pin can not be used to force Boot Loader execution after reset
ALE/HWB pin is used during reset to force bootloader execution after reset
Reset Vector = Application Reset
BOOTRST ?
HWBE
?
(1)
(1)
ALE/HWB
RESET
Table 27-8 on page
Ext. Hardware
Conditions ?
Reset Vector =Boot Lhoader Reset
ATmega16/32U4
t
SHRH
Table
344)
27-5) so that upon
t
HHRH
335