I 2 C Bus Drivers for Windows 2K XP.ppt

I2C Bus Driversfor Windows 2K, XP Pavel Novák Tomá? Matou?ek I2C Basic Characteristics Inter-Integrated Circuts Bus originally to interact within small num. of devs (radio/TV tuning, …) max. speeds: 100 kbps (standard mode) 400 kbps (fast mode) 3.4 Mbps (high-speed mode) data transfers: serial, 8-bit oriented, bi-directional master/slave relationships with multi-master option (arbitration) master can operate as transmitter or receiver addressing: 7bit or 10bit unique addresses Wires and Signals two-wired bus serial data line (SDA) serial clock line (SCL) bit transfer level triggered one clock pulse per data bit stable data during high clocks data change during low clocks Wired-AND Connection open collectors, pull-up resistors bus is free ? SDA and SCL are high Frame Formats Addressing by 7 bits the first byte transmitted by master: 7 bits: address 1 bit: direction (R/W) 0 … master writes data (W) – transmitter since next byte 1 … master reads data (R) – receiver since next byte during the first byte transfer: master is transmitter addressed slave is receiver data transfer terminated by a stop condition master may generate repeated start and address another device Microchip PIC16F628 8-bit 20MHz RISC microcontroller USART Rx, Tx, DTR, DSR for communication RTS resetting, low voltage programming memory FLASH program (2048 x 14bit) RAM data (224B) EEPROM data (128B) hardware stack (8 levels) interrupts, 3 timers, 16 I/O pins 35 instructions single-cycled except for 2-cycled branches Layered Drivers Virtual Network Device Installation Virtual Network Device Installation Virtual Network Device Settings Virtual Network Device Settings NDIS Miniport Implementation Information Transmission – To NDIS NDIS_STATUS MiniportQueryInformation(IN NDIS_HANDLE MiniportAdapterContext,IN NDIS_OID Oid,IN PVOID InformationBuffer,…OUT PULONG BytesWritten,…); Oids:OID_GEN_MEDIA_SUPPORTED // EthernetOID_GEN_LINK_SPEEDOID_GEN_MEDIA_CONNECT_STATUSOID_PNP_CAPABILITIESOID_802