AT90USB1286-16MU ATMEL [ATMEL Corporation], AT90USB1286-16MU Datasheet - Page 259

• Manufacturer Part Number: AT90USB1286-16MU
• Description: Microcontroller with 64/128K Bytes of ISP Flash and USB Controller
• Manufacturer: ATMEL [ATMEL Corporation]

21.9
7593A–AVR–02/06
PAD suspend
EPEN=1
ALLOC=1
clear ALLOC. Then, the “k
“k
The following figure illustrates the allocation and reorganization of the USB memory in a typical
example:
Table 21-1.
Note that:
The next figures illustrates the pad behaviour:
Pipe/Endpoints
• First, Pipe/Endpoint 0 to Pipe/Endpoint 5 are configured, in the growing order. The memory of
• 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
• the data of Pipe/Endpoint 0 are never lost whatever the activation or deactivation of the
• Deactivate and reactivate the same Pipe/Endpoint with the same parameters does not lead
• CFGOK is set by hardware even in the case that there is a “conflict” in the memory allocation.
• In the “idle” mode, the pad is put in low power consumption mode.
• In the “active” mode, the pad is working.
i+2
Free memory
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
both Pipe/Endpoint 4 and 5 use a common area. The data of those endpoints are potentially
lost.
higher Pipe/Endpoint. Its data is lost if it is deactivated.
to a “slide” of the higher endpoints. For those endpoints, the data are preserved.
activation
” and upper Pipe/Endpoint memory does not slide.
5
4
3
2
1
0
Allocation and reorganization USB memory flow
Pipe/Endpoint
Free memory
(ALLOC=1)
i+1
Disable
EPEN=0
” Pipe/Endpoint memory automatically “slides” down. Note that the
5
4
2
1
0
Free its memory
Free memory
Lost memory
(ALLOC=0)
5
4
2
1
0
AT90USB64/128
3 (bigger size)
Pipe/Endpoint
Free memory
Activatation
4
2
1
0
5
Conflict
259