Usb Module Description; Usb Block Diagram - Motorola M68HC08 Designer Reference Manual

Universal Serial Bus (USB) Overview

3.2.1 USB Module Description

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Freescale Semiconductor, Inc.
Figure 3-1 shows a block diagram of the USB module. The USB module
manages communications between the host and the USB function. The module
is partitioned into three functional blocks. These blocks consist of:
• USB transceiver
• USB control logic
• USB registers
CPU BUS
Figure 3-1. USB Block Diagram
The USB transceiver provides the physical interface to the USB D+ and D–
data lines. The USB transceiver uses a differential output driver to drive the
USB data signal onto the USB cable. The output swings between the
differential high and low state are well balanced to minimize signal skew.
The USB control logic manages data movement between the CPU and the
transceiver. The control logic handles both transmit and receive operations on
the USB. It contains the logic used to manipulate the transceiver and the
endpoint registers.
The MCU program controls and monitors the USB operation and data transfer
status through the corresponding USB registers.
Please refer to the MC68HC908JB16 Technical Data (Motorola document
order number MC68HC908JB16/D) and to it's Addendum (Motorola document
order number HC908JB16AD/D) for a more detailed description of each block.
Universal Serial Bus (USB) Overview
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RCV
VPIN
USB
CONTROL
VMIN
LOGIC
VPOUT
VMOUT
USB REGISTERS
High Data Rate Wireless USB Optical Mouse Solution
D +
USB
UPSTREAM
PORT
D –
MOTOROLA