
Universal Serial Bus Interface – On-The-Go Module
Freescale Semiconductor
21-63
21.5.3.4.4
Control Endpoint Operation
Setup Phase
All requests to a control endpoint begin with a setup phase followed by an optional data phase and a
required status phase.
Setup packet managing:
•
Disable setup lockout by setting the setup lockout mode bit (USBMODE[SLOM]), once at
initialization. Setup lockout is not necessary when using the tripwire as described below.
NOTE
Leaving the setup lockout mode cleared results in a potential compliance
issue.
•
After receiving an interrupt and inspecting EPSETUPSR to determine a setup packet was received
on a particular pipe:
1. Write 1 to clear corresponding bit in EPSETUPSR.
2. Set the setup tripwire bit (USBCMD[SUTW]).
3. Duplicate contents of dQH.SetupBuffer into local software byte array.
4. Read the USBCMD[SUTW] bit. If set, continue; if cleared, goto 2)
5. Clear the USBCMD[SUTW] bit.
6. Poll until the EPSETUPSR bit clears.
7. Process setup packet using the local software byte array copy and execute status/handshake phases.
NOTE
After receiving a new setup packet, status and/or handshake phases may
remain pending from a previous control sequence. These should be flushed
and de-allocated before linking a new status and/or handshake dTD for the
most recent setup packet.
Data Phase
Following the setup phase, the DCD must create a device transfer descriptor for the data phase and prime
the transfer.
After priming the packet, the DCD must verify a new setup packet is not received by reading the
EPSETUPSR register immediately verifying that the prime had completed. A prime completes when the
associated bit in the EPPRIME register is cleared and the associated bit in the EPSR register is set. If the
EPPRIME bit goes to 0 and the EPSR bit is not set, the prime fails. This can only happen because of
improper setup of the dQH, dTD, or a setup arriving during the prime operation. If a new setup packet is
indicated after the EPPRIME bit is cleared, then the transfer descriptor can be freed and the DCD must
re-interpret the setup packet.
2
NYET/ACK — NYET unless the transfer descriptor has packets remaining according
to the USB variable length protocol then ACK.
MCF5329 Reference Manual, Rev 3
Содержание MCF5329
Страница 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 126: ...Enhanced Multiply Accumulate Unit EMAC 4 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 564: ...Liquid Crystal Display Controller LCDC 22 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 692: ...Programmable Interrupt Timers PIT0 PIT3 28 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 720: ...Queued Serial Peripheral Interface QSPI 30 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 790: ...Message Digest Hardware Accelerator MDHA 33 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 902: ...Register Memory Map Quick Reference A 26 Freescale Semiconductor MCF5329 Reference Manual Rev 3...