I2C Bus Drivers for Windows 2K, XP

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I2C Bus Driversfor Windows 2K, XP

• Pavel Novák
• Tomáš Matoušek

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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

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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

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Wired-AND Connection

• open collectors, pull-up resistors
• bus is free ? SDA and SCL are high

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Frame Formats
master-transmitter
master-receiver (since second byte)
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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

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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

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Layered Drivers
TCP/IP drivers
TCP/IP drivers
NDIS.sys
NDIS.sys
I2CNET.sys
I2CNET.sys
Ethernet over I2C
I2C.sys
I2C.sys
link layer
Serial.sys
Serial.sys
PC UART
PC UART
PIC16F628
PIC16F628
physical layer
I2C bus
I2C bus
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Virtual Network Device Installation
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Virtual Network Device Installation
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Virtual Network Device Settings
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Virtual Network Device Settings
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Network Driver Interface Specification (NDIS)

• Common interface for network drivers
• specification not only for device drivers
• includes
• Miniport drivers
• Intermediate drivers
• Protocol drivers

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NDIS Miniport Implementation

• DriverEntry()
• driver initialization
• calls NdisMRegisterMiniport()
• informs NDIS about new Miniport driver
• MiniportInitialize()
• called by NDIS for each instance of network
  controller device
• MiniportHalt()
• MiniportReset()
• MiniportShutdown()

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Information Transmission To NDIS

• NDIS_STATUS MiniportQueryInformation(IN
  NDIS_HANDLE MiniportAdapterContext,IN
  NDIS_OID Oid,IN PVOID InformationBuffer,OUT
  PULONG BytesWritten,)
• OidsOID_GEN_MEDIA_SUPPORTED //
  EthernetOID_GEN_LINK_SPEEDOID_GEN_MEDIA_CONNECT_
  STATUSOID_PNP_CAPABILITIESOID_802_3_PERMANENT_AD
  DRESSOID_GEN_XMIT_OK

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Information Transmission To Our Driver

• NDIS_STATUS MiniportSetInformation(IN
  NDIS_HANDLE MiniportAdapterContext,IN
  NDIS_OID Oid,IN PVOID InformationBuffer,OUT
  PULONG BytesRead,)
• OidsOID_GEN_NETWORK_LAYER_ADDRESSESOID_GEN_CURR
  ENT_PACKET_FILTEROID_PNP_SET_POWER

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Data Transfer To Network

• NDIS_STATUS MiniportSend(IN NDIS_HANDLE MiniportA
  dapterContext,IN PNDIS_PACKET Packet,)
• NdisQueryPacket(Packet,,Buffer)

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Data Transfer From Network

• VOID NdisMEthIndicateReceive(IN
  NDIS_HANDLE MiniportAdapterHandle,IN
  NDIS_HANDLE MiniportReceiveContext,IN
  PVOID HeaderBuffer,IN PVOID LookaheadBuffer,
  IN UINT PacketSize)
• NDIS_STATUS MiniportTransferData(OUT
  PNDIS_PACKET Packet,IN NDIS_HANDLE MiniportAdap
  terContext,IN NDIS_HANDLE MiniportReceiveContext,
  )

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Further Information

• The I2C Bus Specification, version 2.1, January
  2000
• www.semiconductors.philips.com/buses/i2c
• Microchip PIC16F627/8 Data Sheet
• ww1.microchip.com/downloads/en/DeviceDoc/40300c.p
  df
• WinPic - A PIC Programmer for Windows
• www.qsl.net/dl4yhf/winpicpr.html
• PIC C compiler
• www.ccsinfo.com/picc.shtml