![Texas Instruments AM1808 Скачать руководство пользователя страница 1669](http://html.mh-extra.com/html/texas-instruments/am1808/am1808_technical-reference-manual_10945581669.webp)
Main
Memory
CPU
Interrupts
Queue
Push/Pop
Operations
Queue
Manager
CPPI
DMA
(CDMA)
Queue
Push/Pop
Operations
cdma_sreq
cdma_sready
CDMA
Scheduler
(CDMAS)
Queue Indicators
FIFO_full
FIFO_empty
CPPI
FIFO
FIFO_full
FIFO_empty
Transfer
DMA
(XDMA)
Mentor
USB 2.0
Core
Configuration
Rd/Wr
DMA_req[8]
Endpoint
FIFOs
USB
Bus
CPPI 4.1
USB Controller
RXSQ
Queue 0
RXCQ
Queue 26
Buffer Descriptor (2)
PBD(2)
Buffer
Buffer Descriptor (1)
PBD(1)
Buffer
Next Descriptor Pointer
Buffer Pointer
Buffer Size (256)
Buffer Descriptor (0)
PBD(0)
Data Buffer
(No Valid
Data)
PBD(1)
PBD(2)
PBD(0)
Head
Tail
Queue 0: RXSQ
Head
Tail
Queue 26: RXCQ
Architecture
1669
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Universal Serial Bus 2.0 (USB) Controller
2. The Queue Manager then indicates the status of the TXSQ (empty) to the CDMAS and the TXCQ to
the CPU via an interrupt.
34.2.8.12.2 Receive USB Data Flow Using DMA
The receive descriptors and queue status configuration prior to the transfer taking place is shown in
. An example of initialization for a receive USB data flow is shown in
Figure 34-24. Receive Descriptors and Queue Status Configuration
Figure 34-25. Receive USB Data Flow Example (Initialization)