
Universal Serial Bus Interface – On-The-Go Module
Freescale Semiconductor
21-75
— QH.EPS equals port speed
•
Transactions to a device downstream from direct attached FS hub.
— QH.EPS equals downstream device speed
NOTE
When QH.EPS equals 01 (LS) and PORTSC
n
[PSPD] equals 00 (FS), a
LS-pre-PID is sent before transmitting LS traffic.
Maximum packet size must equal 64 or less to prevent undefined behavior.
2. siTD (for direct attach FS) – Periodic (ISO endpoint)
•
All FS ISO transactions:
— Hub address equals 0
— siTD.EPS equals 00 (full speed)
Maximum packet size must equal to 1023 or less to prevent undefined behavior.
21.5.5.1.5
Operational Model
The operational models are well defined for the behavior of the transaction translator (see USB 2.0
specification) and for the EHCI controller moving packets between system memory and a USB-HS hub.
Because the embedded transaction translator exists within the USB host controller, no physical bus
between EHCI host controller driver and the USB FS/LS bus. These sections briefly discuss the
operational model for how the EHCI and transaction translator operational models combine without the
physical bus between. The following sections assume the reader is familiar with the EHCI and USB 2.0
transaction translator operational models.
Microframe Pipeline
The EHCI operational model uses the concept of H-frames and B-frames to describe the pipeline between
the host (H) and the bus (B). The embedded transaction translator uses the same pipeline algorithms
specified in the USB 2.0 specification for a hub-based transaction translator.
All periodic transfers always begin at B-frame 0 (after SOF) and continue until the stored periodic transfers
are complete. As an example of the microframe pipeline implemented in the embedded transaction
translator, all periodic transfers that are tagged in EHCI to execute in H-frame 0 are ready to execute on
the bus in B-frame 0.
When programming the S-mask and C-masks in the EHCI data structures to schedule periodic transfers
for the embedded transaction translator, the EHCI host controller driver must follow the same rules
specified in EHCI for programming the S-mask and C-mask for downstream hub-based transaction
translators.
After periodic transfers are exhausted, any stored asynchronous transfer is moved. Asynchronous transfers
are opportunistic because they execute when possible and their operation is not tied to H-frame and
B-frame boundaries with the exception that an asynchronous transfer cannot babble through the SOF (start
of B-frame 0.)
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...