ATMEGA16U2-16AU Atmel, ATMEGA16U2-16AU Datasheet - Page 199

• 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

21.7
7799D–AVR–11/10
Address Setup
Figure 21-2. Endpoint activation flow:
As long as the endpoint is not correctly configured (CFGOK cleared), the hardware does not
acknowledge the packets sent by the host.
CFGOK will not be set if the Endpoint size parameter is bigger than the DPRAM size.
A clear of EPEN acts as an endpoint reset (see
It also performs the next operation:
S e e
allocation/reorganization.
The USB device address is set up according to the USB protocol:
ADDEN and UADD shall not be written at the same time.
• The configuration of the endpoint is kept (EPSIZE, EPBK, ALLOC kept)
• It resets the data toggle field.
• The DPRAM memory associated to the endpoint is still reserved.
• the USB device, after power-up, responds at address 0
• the host sends a SETUP command (SET_ADDRESS(addr)),
• the firmware records that address in UADD, but keep ADDEN cleared,
• the USB device sends an IN command of 0 bytes (IN 0 Zero Length Packet) to acknowledge
• then, the firmware may enable the USB device address by setting ADDEN. The only
the transaction,
accepted address by the controller is the one stored in UADD.
“ M e m o r y m a n a g e m e n t ” o n p a g e 1 9 2
“Endpoint reset” on page 197
ATmega8U2/16U2/32U2
f o r m o r e d e t a i l s a b o u t t h e m e m o r y
for more details).
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