CommSM

CommSM State Machine

CommSM Psuedocode

/******************************************************************************/

COMM MODULE STATE MACHINE PSEUDO-CODE

InitCommSM

Takes a priority number, returns True

Initialize the MyPriority variable with the passed in parameter

Initialize CommTimer

Set CurrentState to be InitCommSM

post Event ES_INIT to InitCommSM (this service)

End

RunCommSM (implements the state machine for COMM)

The EventType field of ThisEvent will be of one: ES_INIT, ES_SENDREQ, ES_TIMEOUT

List of States: InitCommSM, Idle, WaitForStrobeFall, WaitForACK, StrobeRise, StrobeFall, ACKRise

Returns ES_NO_EVENT

Module Variables:

Set NextState to CurrentState

Based on the state of the CurrentState variable, choose one of the following blocks of code:

CurrentState is InitCommPState

IF ThisEvent is ES_INIT

Do initialization

Set NextState to Idle

ENDIF

CurrentState is Idle

IF ThisEvent is ES_SENDREQ

IF Strobe Asserted (Strobe pin is High)

Defer ES_SENDREQ

Set NextState to Idle

ENDIF

IF Strobe Not Asserted

Save NewData

Assert Data

Assert Strobe

Start CommTimer

Set NextState to WaitForACK

ENDIF

IF ThisEvent is StrobeRise

Read Data

Assert ACK

Set NextState to WaitForStrobeFall

ENDIF

CurrentState is WaitForStrobeFall

IF ThisEvent is StrobeFall

Deassert ACK

Decode Data (int data[pin1][pin2][pin3])

Post Data

Recall ES_SENDREQ

Set NextState to Idle

ENDIF

IF ThisEvent is ES_SENDREQ

Defer ES_SENDREQ

set NextState to WaitForStrobeFall

ENDIF

CurrentState is WaitForACK

IF ThisEvent is ACKRise

Deassert data and strobe

Post SendCompleted

Recall ES_SENDREQ

ENDIF

IF ThisEvent is ES_SENDREQ

Defer ES_SENDREQ

Set NextState to WaitForACK

ENDIF

IF ThisEvent is ES_TIMEOUT and Event.Param is CommTimer Number

Re-Post ES_SENDREQ with saved data

Set NextState to Idle

ENDIF

Set CurrentState to NextState