The features of the USB module include:

  • Fully compliant with the USB 2.0 full-speed specification
  • Full-speed device (12 Mbps) with integrated USB transceiver (PHY)
  • Up to eight input and eight output endpoints
  • Supports control, interrupt, and bulk transfers
  • Supports USB suspend, resume, and remote wakeup
  • A power supply system independent from the PMM system
  • Integrated 3.3-V LDO regulator with sufficient output to power entire MSP430 and system circuitry
  • from 5-V VBUS
  • Integrated 1.8-V LDO regulator for PHY and PLL
  • Easily used in either bus-powered or self-powered operation
  • Current-limiting capability on 3.3-V LDO output
  • Autonomous power-up of device on arrival of USB power possible (low or no battery condition)
  • Internal 48-MHz USB clock
  • Integrated programmable PLL
  • Highly-flexible input clock frequencies for use with lowest-cost crystals
  • 1904 bytes of dedicated USB buffer space for endpoints, with fully configurable size to a granularity of eight bytes
  • Timestamp generator with 62.5-ns resolution
  • When USB is disabled
  • Buffer space is mapped into general RAM, providing additional 2KB to the system
  • USB interface pins become high-current general purpose I/O pins

NOTE: Use of the word device

The word device is used throughout the chapter. This word can mean one of two things, depending on the context. In a USB context, it means what the USB specification refers to as a device, function, or peripheral; that is, a piece of equipment that can be attached to a USB host or hub. In a semiconductor context, it refers to an integrated circuit such as then MSP430. To avoid confusion, the term USB device in this document refers to the USB-context meaning of the word. The word device by itself refers to silicon devices such as the MSP430.

Figure 42-1 shows a block diagram of the USB module.