TUSB3200 Datasheet, PDF (18/93 Pages) Texas Instruments – USB Streaming Controller STC

2.1.6 USB Buffer Manager (UBM)
The USB buffer manager provides the control logic that interfaces the SIE to the USB endpoint buffers. One of the
major functions of the UBM is to decode the USB function address to determine if the host PC is addressing the
TUSB3200 device USB peripheral function. In addition, the endpoint address field and direction signal are decoded
to determine which particular USB endpoint is being addressed. Based on the direction of the USB transaction and
the endpoint number, the UBM will either write or read the data packet to/from the appropriate USB endpoint data
buffer.
2.1.7 USB Frame Timer
The USB frame timer logic receives the start of frame (SOF) packet from the host PC each USB frame. Each frame,
the logic stores the 11-bit frame number value from the SOF packet in a register and asserts the internal SOF signal.
The frame number register can be read by the MCU and the value can be used as a time stamp. For USB frames
in which the SOF packet is corrupted or not received, the frame timer logic will generate a pseudo start of frame
(PSOF) signal and increment the frame number register.
2.1.8 USB Suspend and Resume Logic
The USB suspend and resume logic detects suspend and resume conditions on the USB. This logic also provides
the internal signals used to control the TUSB3200 device when these conditions occur. The capability to resume
operation from a suspend condition with a locally generated remote wake-up event is also provided.
2.1.9 MCU Core
The TUSB3200 uses an 8-bit microcontroller core that is based on the industry standard 8052. The MCU is software
compatible with the 8052, 8032, 80C52, 80C53, and 87C52 MCUs. The 8052 MCU is the processing core of the
TUSB3200 and handles all USB control, interrupt and bulk endpoint transfers. In addition, the MCU can also be the
source or sink for USB isochronous endpoint transfers.
2.1.10 MCU Memory
In accordance with the industry standard 8052, the TUSB3200 MCU memory is organized into program memory,
external data memory and internal data memory. A 4K byte boot ROM is used to download the application code to
an 8K byte RAM that is mapped to the program memory space. The external data memory includes the USB endpoint
configuration blocks, USB data buffers, and memory mapped registers. The total external data memory space used
is 2K bytes. A total of 256 bytes are provided for the internal data memory.
2.1.11 USB Endpoint Configuration Blocks and Endpoint Buffer Space
The USB endpoint configuration blocks are used by the MCU to configure and operate the required USB endpoints
for a particular application. In addition to the control endpoint, the TUSB3200 supports a total of seven in endpoints
and seven out endpoints. A set of six bytes is provided for each endpoint to specify the endpoint type, buffer address,
buffer size and data packet byte count.
The USB endpoint buffer space provided is a total of 1832 bytes. The space is totally configurable by the MCU for
a particular application. Therefore, the MCU can configure each buffer based on the total number of endpoints to be
used, the maximum packet size to be used for each endpoint, and the selection of single or double buffering.
2.1.12 DMA Controller
Four DMA channels are provided to support the streaming of data for USB isochronous endpoints. Each DMA channel
can support one USB isochronous endpoint, either in or out. The DMA channels are used to stream data between
the USB endpoint data buffers and the CODEC port interface. The USB endpoint number and direction can be
programmed for each DMA channel. Also, the CODEC port interface time slots to be serviced by each DMA channel
can be programmed.
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