ATMEGA16U2-16AU Atmel, ATMEGA16U2-16AU Datasheet - Page 192

• 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

20.5.3
20.6
7799D–AVR–11/10
Memory management
Freeze clock
The firmware has the ability to freeze the clock of USB controller by setting the FRZCLK bit, and
thereby reduce the power consumption. When FRZCLK is set, it is still possible to access to the
following registers:
When FRZCLK is set, only the asynchronous interrupt may be triggered:
The controller does only support the following memory allocation management.
The reservation of an Endpoint can only be made in the increasing order (Endpoint 0 to the last
Endpoint). The firmware shall thus configure them in the same order.
The reservation of an Endpoint k
cates the memory and insert it between the Endpoints k
“slides” up and its data is lost. Note that the k
Clearing an Endpoint enable (EPEN) does not clear either its ALLOC bit, or its configuration
(EPSIZE/PSIZE, EPBK/PBK). To free its memory, the firmware should clear ALLOC. Then, the
k
does not slide.
The following figure illustrates the allocation and reorganization of the USB memory in a typical
example:
Table 20-1.
i+1
• USBCON
• DPRAM direct access registers (DPADD7:0, UEDATX)
• UDCON
• UDINT
• UDIEN
• WAKEUPI
Endpoint memory automatically slides down. Note that the k
Allocation and reorganization USB memory flow
i
is done when its ALLOC bit is set. Then, the hardware allo-
i+2
and upper Endpoint memory does not slide.
ATmega8U2/16U2/32U2
i-1
and k
i+2
i+1
and upper Endpoint memory
. The k
i+1
Endpoint memory
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