DOC7707 datasheet(191/307 Pages) ETC1

191 / 307 page

191

7707F–AVR–11/10

AT90USB82/162

Table 19-1.

Allocation and reorganization USB memory flow

• First, Endpoint 0 to Endpoint 4 are configured, in the growing order. The memory of each is

reserved in the DPRAM.

• Then, the Endpoint 2is disabled (EPEN=0), but its memory reservation is internally kept by

the controller.

• Its ALLOC bit is cleared: the Endpoint 3 “slides” down, but the Endpoint 4 does not “slide”.

• Finally, the firmware chooses to reconfigure the Endpoint 2, but with a bigger size. The

controller reserved the memory after the endpoint 1 memory and automatically “slide” the

Endpoint 3. The Endpoint 4 does not move and a memory conflict appear, in that both

Endpoint 3 and 4 use a common area. The data of those endpoints are potentially lost.

Note that :

• the data of Endpoint 0 are never lost whatever the activation or deactivation of the higher

Endpoint. Its data is lost if it is deactivated.

• Deactivate and reactivate the same Endpoint with the same parameters does not lead to a

“slide” of the higher endpoints. For those endpoints, the data are preserved.

• CFGOK is set by hardware even in the case that there is a “conflict” in the memory allocation.

19.7

PAD suspend

The next figures illustrates the pad behaviour:

• In the “idle” mode, the pad is put in low power consumption mode.

• In the “active” mode, the pad is working.

Free memory

EPEN=1

ALLOC=1

Free memory

EPEN=0

(ALLOC=1)

Free memory

Lost memory

Endpoints

activation

Endpoint Disable

Free its memory

(ALLOC=0)

Free memory

2 (bigger size)

Endpoint

Activatation

Conflict

DOC7707 датащи(PDF) 191 Page - List of Unclassifed Manufacturers

DOC7707 датащи(HTML) 191 Page - List of Unclassifed Manufacturers

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL