Components of an MMlite Project

1
Components of an MMlite Project

• Richard Neil Pittman
• Texas AM University
• 2006

2
MMlite Project Hierarchy

• Client Program (.cpp ? .exe)
• Driver ((.c .h) ? .cob)
• Object File (.c)
• .c File
• .h File
• Note A project can contain multiple drivers.

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MMlite Projects

• Client Program The top level software
  application that creates and releases instances
  of driver objects and request services from them.
• Driver A software object that provides services
  through functions that can be called by a client
  program. This driver can interface to a
  peripheral device or encapsulate software
  components

4
Drivers
5
.c File

• This file contains the GUID for your driver.
  This must be a unique number for each driver.
  Use the GUID tool from Visual Studio to generate
  these.

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.h File

• This file contains the v-table for your driver.
  The v-table is a directory of the functions
  contained within this driver that are available
  to clients.

7
Object File

• Must include the .c .h files for this driver.

8
Object File

• Declare and instantiate v-table.

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Object File

• All drivers include QueryInterface(), AddRef()
  Release() Functions

10
Object File

• Declare and implement the Driver Functions

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Object File

• Populate the v-table with Driver Functions.
• IMPORTANT The functions listed must be in the
  same order they are listed in the .h File

12
Object File

• All drivers must have an initialization function
  to setup driver resources. (reference, pins,
  variables, etc.)

13
Object File

• The initialization function must be called within
  the CobMain() of the driver

14
Client Program
15
Client Program

• Must include the .c .h files for all drivers
  used by this client program

16
Client Program

• Declare driver object pointers.

17
Client Program

• Assign pointer to current namespace.

18
Client Program

• Bind driver cob to unknown object.

19
Client Program

• Query the driver interface and enter application
  loop.