Table 42-5. Buffer descriptor fields (continued)
Field
Description
7
OWN
Determines whether the processor or USBFS currently owns the buffer. Except when KEEP=1, the
SIE hands ownership back to the processor after completing the token by clearing this bit.
This must always be the last byte of the BD that the processor updates when it initializes a BD.
0 The processor has access to the BD. USBFS ignores all other fields in the BD.
1 USBFS has access to the BD. While USBFS owns the BD, the processor should not modify any
other fields in the BD.
6
DATA0/1
Defines whether a DATA0 field (DATA0/1=0) or a DATA1 (DATA0/1=1) field was transmitted or
received. It is unchanged by USBFS.
5
KEEP/
TOK_PID[3]
This bit has two functions:
• KEEP bit—When written by the processor, it serves as the KEEP bit. Typically, this bit is 1
with ISO endpoints feeding a FIFO. The microprocessor is not informed that a token has
been processed, the data is simply transferred to or from the FIFO. When KEEP is set,
normally the NINC bit is also set to prevent address increment.
0 Allows USBFS to release the BD when a token has been processed.
1 This bit is unchanged by USBFS. Bit 3 of the current token PID is written back to the BD by
USBFS.
• TOK_PID[3]—If the OWN bit is also set, the BD remains owned by USBFS indefinitely; when
written by USB, it serves as the TOK_PID[3] bit.
0 or 1 Bit 3 of the current token PID is written back to the BD by USBFS.
Typically, this bit is 1 with ISO endpoints feeding a FIFO. The microprocessor is not informed that a
token has been processed, the data is simply transferred to or from the FIFO. When KEEP is set,
normally the NINC bit is also set to prevent address increment.
4
NINC/
TOK_PID[2]
No Increment (NINC)
Disables the DMA engine address increment. This forces the DMA engine to read or write from the
same address. This is useful for endpoints when data needs to be read from or written to a single
location such as a FIFO. Typically this bit is set with the KEEP bit for ISO endpoints that are
interfacing to a FIFO.
0 USBFS writes bit 2 of the current token PID to the BD.
1 This bit is unchanged by USBFS.
3
DTS/
TOK_PID[1]
Setting this bit enables USBFS to perform Data Toggle Synchronization.
• If KEEP=0, bit 1 of the current token PID is written back to the BD.
• If KEEP=1, this bit is unchanged by USBFS.
0 Data Toggle Synchronization is disabled.
1 Enables USBFS to perform Data Toggle Synchronization.
Table continues on the next page...
Programmers interface
K22F Sub-Family Reference Manual , Rev. 3, 7/2014
996
Freescale Semiconductor, Inc.
Содержание MK22FN256VDC12
Страница 2: ...K22F Sub Family Reference Manual Rev 3 7 2014 2 Freescale Semiconductor Inc...
Страница 136: ...Human machine interfaces K22F Sub Family Reference Manual Rev 3 7 2014 136 Freescale Semiconductor Inc...
Страница 164: ...Module clocks K22F Sub Family Reference Manual Rev 3 7 2014 164 Freescale Semiconductor Inc...
Страница 246: ...Functional description K22F Sub Family Reference Manual Rev 3 7 2014 246 Freescale Semiconductor Inc...
Страница 328: ...Kinetis Flashloader Status Error Codes K22F Sub Family Reference Manual Rev 3 7 2014 328 Freescale Semiconductor Inc...
Страница 360: ...Functional description K22F Sub Family Reference Manual Rev 3 7 2014 360 Freescale Semiconductor Inc...
Страница 388: ...Functional description K22F Sub Family Reference Manual Rev 3 7 2014 388 Freescale Semiconductor Inc...
Страница 402: ...Initialization application information K22F Sub Family Reference Manual Rev 3 7 2014 402 Freescale Semiconductor Inc...
Страница 500: ...Initialization application information K22F Sub Family Reference Manual Rev 3 7 2014 500 Freescale Semiconductor Inc...
Страница 670: ...Flash memory map for EzPort access K22F Sub Family Reference Manual Rev 3 7 2014 670 Freescale Semiconductor Inc...
Страница 680: ...Functional description K22F Sub Family Reference Manual Rev 3 7 2014 680 Freescale Semiconductor Inc...
Страница 744: ...Application information K22F Sub Family Reference Manual Rev 3 7 2014 744 Freescale Semiconductor Inc...
Страница 784: ...Functional description K22F Sub Family Reference Manual Rev 3 7 2014 784 Freescale Semiconductor Inc...
Страница 794: ...Initialization Application Information K22F Sub Family Reference Manual Rev 3 7 2014 794 Freescale Semiconductor Inc...
Страница 960: ...Example configuration for chained timers K22F Sub Family Reference Manual Rev 3 7 2014 960 Freescale Semiconductor Inc...
Страница 1036: ...Device mode IRC48 operation K22F Sub Family Reference Manual Rev 3 7 2014 1036 Freescale Semiconductor Inc...
Страница 1040: ...USB Voltage Regulator Module Signal Descriptions K22F Sub Family Reference Manual Rev 3 7 2014 1040 Freescale Semiconductor Inc...
Страница 1094: ...Initialization application information K22F Sub Family Reference Manual Rev 3 7 2014 1094 Freescale Semiconductor Inc...
Страница 1128: ...Initialization application information K22F Sub Family Reference Manual Rev 3 7 2014 1128 Freescale Semiconductor Inc...
Страница 1216: ...Application information K22F Sub Family Reference Manual Rev 3 7 2014 1216 Freescale Semiconductor Inc...
Страница 1298: ...Functional description K22F Sub Family Reference Manual Rev 3 7 2014 1298 Freescale Semiconductor Inc...
Страница 1312: ...K22F Sub Family Reference Manual Rev 3 7 2014 1312 Freescale Semiconductor Inc...