1 / 6

Universal Serial Interface USI

CS423 Dick Steflik. Universal Serial Interface USI. What is it for?. Basic hardware needed for serial comm: SPI (4-wire bus) ‏ MMC/SD Ethernet, UARTs, USARTs, JTAG (IEEE 1149.1) ‏ I2C/TWI (Inter-Integrated Circuit) (2/3-wire bus) ‏

jorden-kent
Télécharger la présentation

Universal Serial Interface USI

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CS423 Dick Steflik Universal Serial InterfaceUSI

  2. What is it for? • Basic hardware needed for serial comm: • SPI (4-wire bus)‏ • MMC/SD • Ethernet, UARTs, USARTs, • JTAG (IEEE 1149.1)‏ • I2C/TWI (Inter-Integrated Circuit) (2/3-wire bus)‏ • appropriate for peripherals where simplicity and low manufacturing cost are more important than speed • Accessing DACs and ADCs • Interfacing OLEDs/LCDs • Computer diagnistic sensors (fans, overtemp)

  3. USI Block Diagram

  4. USI Data Register • 8-bit, parallel load/read shift register • SFR I/O8 (0x0F)‏ • Port B • PB5 - DI/SDA • PB6 - DO • PB7 – UCSK/SCL • Must set DDR for Port B appropriately • Data must be read from USIDR immediately as the register is not buffered

  5. USI Status register • 7 – USISIF – Start Cond. Interrupt Flag • 6 – USIOIF – Counter Overflow Interrupt Flag • 5 – USIPF – Stop Cond. Interrupt Flag • 4 – USIDC – Data Output Collision • 3 – USICNT3 – 4-bit Counter MSB • 2 - USICNT2 • 1 - USICNT1 • 0 – USICNT0 – 4-bit Counter LSB

  6. USI Control Register • 7 – USISIE – Start Cond. Interrupt Enable • 6 – USIOIE – Counter Overflow Interrupt Enable • 5 & 4 - USWWM1..0 – Wire Mode • 3 & 2 - USICS1..0 – Clock Select • 1 – USICLK - • 0 – USITC – USI Timer/Counter Strobe bit

More Related