HCI GUI Tool #2

HCI GUI Tool #2

topic>

HCI spec study.

contents>

-HCI: Host Controller Interface

-HCI는 interface시에 총 4 type의 packet을 사용하여 통신함.

1. packets: there are 4 types of packet.

-HCI command packet (host -> controller)

-HCI ACL data packet (bi-directional)

-HCI synchronous data packet (bi-directional)

-HCI event packet (controller -> host)

 1)HCI command packet

  -format: OpCode(16 bit) + Parameter length(16 bit) + Parameter + ....

  -OpCode is consist of OGF, OCF.

    .OGF(OpCode Group Field): upper 6 bits

    .OCF(OpCode Command Field): remaining 10 bits

      => OpCode (16bits) = OCF(10bits) + OGF(6bits)

    so, Command packet = OCF(10bits) + OGF(6bits) + Para length(16bits) 로 구성됨.

    .OGF라는 category안에 여러개의 OCF가 존재하는 형태.

      -OGF=0x01: HCI Link Control Commands

      -OGF=0x02: HCI Link Policy Commands:

      -OGF=0x03: HCI Host Controller & BB Commands

      -OGF=0x04: HCI Informational Parameters

      -OGF=0x05: HCI Status Parameters

      -OGF=0x06: HCI Testing Commands.

      -OGF=0x3e: TCI-L2CAP

      -OGF=0x3f: HCI Vendor Commands

 2)HCI event packet

ex) "Read_BD_ADDR" command 입력시 전달되는 packet.

  > Read_BD_ADDR is in 'Information Parameters' Group. so, OGF: 0x04(0000 0100)
  > and its OCF: 0x0009(0000 0000 0000 1001)
  > 따라서 전체 OpCode의 상위 6bits를 구성하는 OGF는 => 00 0100 (0x04)
     remaining 10bits 인 OCF는 => 00 0000 1001(0x009)
     combining above 2 terms(OGF+OCF), total OpCode is "0001 0000 0000 1001"(0x1009)
  > 즉, 총 16bit의 OpCode이며, upper 6bits는 0x04(means "Information Parameters"Group),
     remaining 10bits는 0x0009(means "Read_BD_ADDR")
  > 이를 command packet 형식에 맞게 mapping하면
     OpCode packet = OCF + OGF 이므로
                             = 0x09 + 0x10 = 0000 1001 0001 0000 의 형태로 mapping