K60P100M100SF2RM Datasheet, PDF (1239/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Chapter 45 Universal Serial Bus OTG Controller (USBOTG)
The USB-FS Controller uses the data stored in the BDs to determine:
• Who owns the buffer in system memory
• Data0 or Data1 PID
• Release Own upon packet completion
• No address increment (FIFO Mode)
• Data toggle synchronization enable
• How much data is to be transmitted or received
• Where the buffer resides in system memory
While the microprocessor uses the data stored in the BDs to determine:
• Who owns the buffer in system memory
• Data0 or Data1 PID
• The received TOKEN PID
• How much data was transmitted or received
• Where the buffer resides in system memory
The format for the BD is shown in the following figure.
Table 45-3. Buffer Descriptor Byte Format
31:26
RSVD
25:16
BC
(10 bits)
15:8
RSVD
7
OWN
6
5
4
KEEP/
NINC/
DATA0/1
TOK_PID[3] TOK_PID[2]
Buffer Address (32-Bits)
3
DTS/
TOK_PID[1]
2
BDT_STALL/
TOK_PID[0]
10
00
Field
31 –26
RSVD
25 –16
BC[9:0]
15 –8
RSVD
Table 45-4. Buffer Descriptor Byte Fields
Description
Reserved
The Byte Count bits represent the 10-bit Byte Count. The USB-FS SIE changes this field upon the
completion of a RX transfer with the byte count of the data received.
Reserved
Table continues on the next page...
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.
1239