AT90USB647-MU Atmel, AT90USB647-MU Datasheet - Page 257

• Manufacturer Part Number: AT90USB647-MU
• Description: MCU, 8BIT, 64K FLASH, USB, 64QFN
• Manufacturer: Atmel

Specifications of AT90USB647-MU

• Controller Family/series: AT90
• No. Of I/o's: 48
• Eeprom Memory Size: 2KB
• Ram Memory Size: 4KB
• Cpu Speed: 16MHz
• No. Of: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 64KB
• Oscillator Type: External, Internal
• Package: 64QFN EP
• Device Core: AVR
• Family Name: AT90
• Maximum Speed: 20 MHz
• Ram Size: 4 KB
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 48
• Interface Type: SPI/TWI/USART/USB
• On-chip Adc: 8-chx10-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 4
• Lead Free Status / Rohs Status: Details

21.6.2
21.7
7593K–AVR–11/09
Memory management
Host mode
EPEN=1
ALLOC=1
When the USB interface is configured in host mode, internal Pull Down resistors are activated on
both UDP UDM lines and the interface detects the type of connected device.
The controller does only support the following memory allocation management.
The reservation of a Pipe or an Endpoint can only be made in the increasing order (Pipe/End-
point 0 to the last Pipe/Endpoint). The firmware shall thus configure them in the same order.
The reservation of a Pipe or an Endpoint “k
ware allocates the memory and inserts it between the Pipe/Endpoints “k
Pipe/Endpoint memory “slides” up and its data is lost. Note that the “k
point memory does not slide.
Clearing a Pipe enable (PEN) or 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
and upper Pipe/Endpoint memory does not slide.
The following figure illustrates the allocation and reorganization of the USB memory in a typical
example:
Table 21-1.
Pipe/Endpoints
• First, Pipe/Endpoint 0 to Pipe/Endpoint 5 are configured, in the growing order. The memory
• Then, the Pipe/Endpoint 3 is disabled (EPEN=0), but its memory reservation is internally kept
• Its ALLOC bit is cleared: the Pipe/Endpoint 4 “slides” down, but the Pipe/Endpoint 5 does not
• Finally, if the firmware chooses to reconfigure the Pipe/Endpoint 3, with a bigger size. The
Free memory
of each is reserved in the DPRAM.
by the controller.
“slide”.
controller reserved the memory after the endpoint 2 memory and automatically “slide” the
Pipe/Endpoint 4. The Pipe/Endpoint 5 does not move and a memory conflict appear, in that
activation
5
4
3
2
1
0
Allocation and reorganization USB memory flow
i+1
” Pipe/Endpoint memory automatically “slides” down. Note that the “k
Pipe/Endpoint
Free memory
(ALLOC=1)
Disable
EPEN=0
5
4
2
1
0
i
” is done when its ALLOC bit is set. Then, the hard-
Free its memory
Free memory
Lost memory
(ALLOC=0)
5
4
2
1
0
AT90USB64/128
3 (bigger size)
Pipe/Endpoint
Free memory
Activatation
i+2
i-1
” and upper Pipe/End-
4
” and “k
2
1
0
5
i+1
”. The “k
Conflict
257
i+1
i+2
”
”