i2c总线标准(英文)

i2c总线标准(英文) CONTENTS1 PREFACE. . . . . . . . . . . . . . . . . . . . . . . . . . .31.1 Version 1.0 - 1992. . . . . . . . . . . . . . . . . . . . 31.2 Version 2.0 - 198. . . . . . . . . . . . . . . . . . . . . 31.3 Version 2.1 - 1999. . . . . . . . . . . . . . . . . . . . 31.4 Purchase of Philips I2C-bus components . . 32 THE I2C-BUS BENEFITS DESIGNERSAND MANUFACTURERS. . . . . . . . . . . . . . .42.1 Designer benefits . . . . . . . . . . . . . . . . . . . . 42.2 Manufacturer benefits . . . . . . . . . . . . . . . . . 63 INTRODUCTION TO THE I2C-BUSSPECIFICATION . . . . . . . . . . . . . . . . . . . . .64 THE I2C-BUS CONCEPT . . . . . . . . . . . . . . .65 GENERAL CHARACTERISTICS . . . . . . . . .86 BIT TRANSFER . . . . . . . . . . . . . . . . . . . . . .86.1 Data validity . . . . . . . . . . . . . . . . . . . . . . . . 86.2 START and STOP condiTIons . . . . . . . . . . . 97 TRANSFERRING DATA . . . . . . . . . . . . . . .107.1 Byte format . . . . . . . . . . . . . . . . . . . . . . . . 107.2 Acknowledge. . . . . . . . . . . . . . . . . . . . . . . 108 ARBITRATION AND CLOCKGENERATION . . . . . . . . . . . . . . . . . . . . . .118.1 Synchronization . . . . . . . . . . . . . . . . . . . . 118.2 Arbitration . . . . . . . . . . . . . . . . . . . . . . . . . 128.3 Use of the clock synchronizingmechanism as a handshake . . . . . . . . . . . 139 FORMATS WITH 7-BIT ADDRESSES . . . .1310 7-BIT ADDRESSING . . . . . . . . . . . . . . . . .1510.1 Definition of bits in the first byte . . . . . . . . 1510.1.1 General call address . . . . . . . . . . . . . . . . . 1610.1.2 START byte . . . . . . . . . . . . . . . . . . . . . . . 1710.1.3 CBUS compatibility . . . . . . . . . . . . . . . . . . 1811 EXTENSIONS TO THE STANDARDMODEI2C-BUS SPECIFICATION . . . . . . .1912 FAST-MODE. . . . . . . . . . . . . . . . . . . . . . . .1913 Hs-MODE . . . . . . . . . . . . . . . . . . . . . . . . . .2013.1 High speed transfer. . . . . . . . . . . . . . . . . . 2013.2 Serial data transfer format in Hs-mode . . . 2113.3 Switching from F/S- to Hs-mode andback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2313.4 Hs-mode devices at lower speed modes. . 2413.5 Mixed speed modes on one serial bussystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2413.5.1 F/S-mode transfer in a mixed-speed bussystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2513.5.2 Hs-mode transfer in a mixed-speed bussystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2513.5.3 Timing requirements for the bridge in amixed-speed bus system. . . . . . . . . . . . . . 2714 10-BIT ADDRESSING . . . . . . . . . . . . . . . . 2714.1 Definition of bits in the first two bytes. . . . . 2714.2 Formats with 10-bit addresses. . . . . . . . . . 2714.3 General call address and start byte with10-bit addressing . . . . . . . . . . . . . . . . . . . . 3015 ELECTRICAL SPECIFICATIONSAND TIMING FOR I/O STAGESAND BUS LINES . . . . . . . . . . . . . . . . . . . . 3015.1 Standard- and Fast-mode devices. . . . . . . 3015.2 Hs-mode devices . . . . . . . . . . . . . . . . . . . . 3416 ELECTRICAL CONNECTIONS OFI2C-BUS DEVICES TO THE BUS LINES . 3716.1 Maximum and minimum values ofresistors Rp and Rs for Standard-modeI2C-bus devices . . . . . . . . . . . . . . . . . . . . . 3917 APPLICATION INFORMATION. . . . . . . . . 4117.1 Slope-controlled output stages ofFast-mode I2C-bus devices . . . . . . . . . . . . 4117.2 Switched pull-up circuit for Fast-modeI2C-bus devices . . . . . . . . . . . . . . . . . . . . . 4117.3 Wiring pattern of the bus lines . . . . . . . . . . 4217.4 Maximum and minimum values ofresistors Rp and Rs for Fast-modeI2C-bus devices . . . . . . . . . . . . . . . . . . . . . 4217.5 Maximum and minimum values ofresistors Rp and Rs for Hs-modeI2C-bus devices . . . . . . . . . . . . . . . . . . . . . 4218 BI-DIRECTIONAL LEVEL SHIFTERFOR F/S-MODE I2C-BUS SYSTEMS . . . . 4218.1 Connecting devices with differentlogic levels . . . . . . . . . . . . . . . . . . . . . . . . . 4318.1.1 Operation of the level shifter . . . . . . . . . . . 4419 DEVELOPMENT TOOLS AVAILABLEFROM PHILIPS . . . . . . . . . . . . . . . . . . . . . 4520 SUPPORT LITERATURE . . . . . . . . . . . . . 46