1 / 16

Serial Communication Buses: I 2 C and SPI

Serial Communication Buses: I 2 C and SPI. By Brody Dunn. Goals. Revisit Readings of I 2 C and SPI Not Insult You Realize Level of Understanding Take Next Step Implementation. Inter-Integrated Circuit (I 2 C). 2-Wire Serial Communication Bus Introduced By Philips In 1992

tavorian-ayden
Download Presentation

Serial Communication Buses: I 2 C and SPI

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. Serial Communication Buses: I2C and SPI By Brody Dunn

  2. Goals • Revisit Readings of I2C and SPI • Not Insult You • Realize Level of Understanding • Take Next Step • Implementation

  3. Inter-Integrated Circuit (I2C) • 2-Wire Serial Communication Bus • Introduced By Philips In 1992 • Communication Protocol Between Microcontroller And Peripherals • Real Time Clocks (RTCs) • Analog to Digital Converters (ADCs) • Various Sensors • Many, many, more

  4. I2C Characteristics • Only 2 Wires Needed On Bus • Serial Data (SDA) • Serial Clock (SCL) • Multiple Devices Connected On Bus • Typically Limited (i.e. 8, 20, 27, 210,...?) • Similar Code For All I2C Peripherals • Supports Various Data Transfer Rates

  5. Development of I2C • Version 1.0 Introduced in 1992 • “Standard” 100 Kbits/s • “Fast” 400 Kbits/s • Version 2.0 Released in 1998 • “High-Speed” 3.4 Mbits/s • Version 2.1 Released in 2000 • Clock Stretched • “High-Speed” Timings Relaxed

  6. How Does It Work?

  7. Further Reading • I2C-Bus Specification Version 2.1 • http://www.semiconductors.philips.com/acrobat_download/literature/9398/39340011.pdf • DS1631 Datasheet • http://pdfserv.maxim-ic.com/en/ds/DS1631-DS1731.pdf

  8. Serial Peripheral Interface (SPI) • Synchronous Communication Protocol • 3-Wire (Plus 1 Chip-Select Pin/Device) • Hardware On Microcontroller • Developed By Motorola • “Loose” Standard • Broad Range of Devices Supported • Memory (i.e. EEPROM, RAM, Etc.) • Sensors

  9. SPI Characteristics • 3 Wires (Plus Chip Select Pin/Device) • Master Out Slave In (MOSI) • Master In Slave Out (MISO) • Master/Slave Clock Output/Input (SCK) • Chip/Slave Select (SS) • Multiple Devices Connected On Bus • Limited Only By Number Of uC Pins • Supports Various Data Transfer Rates

  10. How Does It Work?

  11. Configurations (AT89S53) • SPI Control Register (SPCR) • Sets Modes of Operation • SPI Status Register (SPSR) • Checks Flags • SPI Data Register (SPDR) • 8-Bit Shift Register Storing Data

  12. 4 Modes of SPI • Set In SPI Control Register (SPCR) • Clock Polarity • Active Low • Active High • Clock Phase • Data Shifted On Rising Edge • Data Shifted On Falling Edge

  13. 4 Modes of SPI (CPHA = 0)

  14. 4 Modes of SPI (CPHA = 1)

  15. Further Reading • AT89S53 Datasheet (Pg. 8, 14-16) • http://www.atmel.com/dyn/resources/prod_documents/DOC0787.PDF • Pont Ch. 24

  16. SPI Summary • 3-Wire (+ SS/Device) • 1.5 MHz Bit Frequency (AT89S53) • Microcontroller Hardware • Supports Many Devices

More Related