Scenix Lib IO OSI2 IR DA Lap.src

LapInfoSeg		MACRO
;********************************************************************************
;  LAP LAYER
;********************************************************************************
;
;Framing Layer Events
;
;	fl2lapMediaBusy()				;A byte has been received => the media is busy
;
;Payload Layer Events
;
;	pl2lapRxFrame(w=Type)				;Incomming frame of given type
;	pl2lapRxValid()					;Frame was valid
;	pl2lapRxError()					;Frame was invalid
;	pl2lapRxXIDData()				;XID data
;	pl2lapRxIData()					;I data
;	pl2lapRxUIData()				;UI data
;	lap2plRxIgnore()				;Tell the framing layer to ignore the frame
;
;	lap2plSNRMAccept()				;Accept connection and send reply
;	lap2plTxXIDCmd(w=Slot)				;Send a XID command frame
;	lap2plTxXIDRsp()				;Send a XID response frame
;	lap2plTxSimpleRsp()				;Send simple response frame
;	lap2plTxIRsp()					;Send an I frame
;	pl2lapTxIData(ret w=Data ret z=Last) call	;Request for data
;	pl2lapTxComplete()				;Complete indication
;
;	lap2plGenerateNewAddr				;Request that a new 32-bit address be generated
;
;LMP Layer Events
;
;	lap2lmpConnectIndication() call
;	lap2lmpDisconnectIndication()
;	lmp2lapDisconnectRequest()
;
;	lap2lmpRxData(w=Data)				;Incomming data bytes
;	lap2lmpRxValid() call				;Data bytes passed since RxFrame message are valid
;	lap2lmpRxError() call				;Data bytes passed since RxFrame message are invalid
;
;	lap2lmpTxFrame(ret z=None) call			;Lap layer can transmit a i-frame and will do so if z is returned false
;	lap2lmpTxData(ret w=Data ret z=Last) call	;Payload layer can accept a data byte (for an I frame) if there is one available. if there is data available then lmp returns data byte and sets z to false
;	lap2lmpTxValid() call				;Lap layer is indicating that all data passed since last TxStart message was acknowledged
;	lap2lmpTxError() call				;Lap layer is indicating that all data passed since last TxStart message will need to be sent again
;
;Application Events
;
;	app2lapDiscoveryRequest(ret z=Busy)		;Application wishes to initiate the XID discovery process
;	app2lapTxUIStart(ret z=Busy)			;Application wishes to send a UI command frame
;
;********************************************************************************
			ENDM


LapDataSeg		MACRO
;********************************************************************************
;  LAP LAYER
;********************************************************************************

		org	$70

lapBank		= 	$70				;8 bytes used

lapState	ds	1				;Current lap state
lapRxFrame	ds	1
lapRxData	ds	1
lapTxXIDSlot	ds	1

lapStatus	ds	1				;Status bits
lapRemoteBusy	=	lapStatus.0			;Remote busy flag
lapXIDDataFlag	=	lapStatus.1			;Indication that host has been informed that XID data will follow
lapRxUIDataFlag	=	lapStatus.2			;Indication that app layer has been informed that UI data will follow
lapTxUIDataFlag	=	lapStatus.3			;Indication that app layer has been informed that UI data will follow
lapLmpRxFlag	=	lapStatus.4			;Indication that lmp layer has sent data that has not been acknowledged
lapLmpTxFlag	=	lapStatus.5			;Indication that lmp layer has sent data that has not been acknowledged
lapMediaIdle	=	lapStatus.6			;Indication that the media has not been used in the past 500ms (NDM state only)

lapRxNs		ds	1				;%.....nnn = expected next I-frame sequence number (Ns)
lapRxNrAck	ds	1				;%.....nnn = expected next I-response sequence number if last frame that was transmitted has been acknowledged
lapRxNrNotAck	ds	1				;%.....nnn = expected next I-response sequence number if last frame that was transmitted has been not-acknowledged

lapNDMState		= 0				;NDM state
lapQUERYState		= 1				;QUERY state
lapNDM2NRMState		= 2				;internal state to wait for TxComplete so new connection parameters can be applied
lapNRMState		= 3				;NRM state
lapSCLOSEState		= 4				;SCLOSE state
lapSCLOSE2NDMState	= 5				;internal state to wait for TxComplete so default connection parameters can be applied

lapMaxFrameSize		= 64				;Max frame size = 64 bytes
lapMinTurnaround	= 116				;Number of additional BOFs to send @ 115200bps (116 = 10ms, 58 = 5ms)

Timer140ms		= -1				;1  =  1*256*256*108*(1/50MHz) =  141.56ms
Timer570ms		= -4				;4  =  4*256*256*108*(1/50MHz) =  566.23ms
Timer1000ms		= -7				;7  =  7*256*256*108*(1/50MHz) =  990.90ms
Timer3000ms		= -21				;21 = 21*256*256*108*(1/50MHz) = 2972.72ms
							;Note - For a different clock frequency the 108 ISR constant changes => these timeout numbers remain the same

;********************************************************************************
			ENDM


LapCodeSeg		MACRO
;********************************************************************************
;  LAP LAYER
;********************************************************************************

;********** a2lapReset **********

a2lapReset
	call	@lap2plGenerateNewAddr			;Generate new device address
	bank	lapBank
	mov	lapState, #lapNDMState			;Enter NDM state
	clr	lapStatus				;Init status
	jmp	lapMediaBusy				;Reset media idle detection (lapMediaBusy will issue retp instruction)

;********** a2lapTimer **********

a2lapTimer
	clrb	TimerOverflow				;Clear Timer flag
	bank	lapBank
	mov	w, lapState				;jump based on state
	jmp	PC+w
	jmp	lapNDMTimer				; 0 = lapNDMState
	jmp	lapQUERYTimer				; 1 = lapQUERYState
	retp						; 2 = lapNDM2NRMState
	jmp	lapNRMTimer				; 3 = lapNRMState
	jmp	lapSCLOSETimer				; 4 = lapSCLOSEState
	retp						; 5 = lapSCLOSE2NDMState

;********** pl2lapRxFrame **********

pl2lapRxFrame
	bank	lapBank
	mov	lapRxFrame, w				;Store frame type
	mov	w, lapState				;Jump based on state
	jmp	PC+w
	jmp	lapNDMRxFrame				; 0 = lapNDMState
	jmp	lapQUERYRxFrame				; 1 = lapQUERYState
	retp						; 2 = lapNDM2NRMState (RxFrame = impossable in this state)
	jmp	lapNRMRxFrame				; 3 = lapNRMState
	jmp	lapSCLOSERxFrame			; 4 = lapSCLOSEState
	retp						; 5 = lapSCLOSE2NDMState (RxFrame = impossable in this state)

;********** pl2lapRxValid **********

pl2lapRxValid
	bank	lapBank
	mov	w, lapState				;Jump based on state
	jmp	PC+w
	jmp	lapNDMRxValid				; 0 = lapNDMState
	jmp	lapQUERYRxValid				; 1 = lapQUERYState
	retp						; 2 = lapNDM2NRMState (RxValid is impossable in this state)
	jmp	lapNRMRxValid				; 3 = lapNRMState
	jmp	lapSCLOSERxValid			; 4 = lapSCLOSEState
	retp						; 5 = lapSCLOSE2NDMState (RxValid is impossable in this state)

;********** pl2lapRxValid - NRM State **********

lapNRMRxValid
	mov	w, lapRxFrame				;Jump based on frame type
	jmp	PC+w
	jmp	lapNRMXCmdValid				;xFrame		=	0
	jmp	lapNRMIValid				;iFrame		=	1
	jmp	lapNRMRRValid				;sRRFrame	=	2
	jmp	lapNRMRNRValid				;sRNRFrame	=	3
	jmp	lapNRMREJValid				;sREJFrame	=	4
	jmp	lapNRMSREJValid				;sSREJFrame	=	5
	jmp	lapNRMXCmdValid				;uUIFrame	=	6	;UICmd or UIRsp (same command)
	jmp	lapNRMDISCValid				;uDISCFrame	=	7	;DISCCmd or RDRsp (same command)
	jmp	lapNRMXCmdValid				;uUARspFrame	=	8	;UARsp
	jmp	lapNRMNRMValid				;uNRMFrame	=	9	;SNRMCmd or RNRMRsp (same command)
	jmp	lapNRMXCmdValid				;uTESTFrame	=	10	;TESTCmd or TESTRsp (same command)
	jmp	lapNRMXCmdValid				;uFRMRRspFrame	=	11	;FRMRRsp
	jmp	lapNRMXCmdValid				;uDMRspFrame	=	12	;DMRsp
	jmp	lapNRMXCmdValid				;uXIDCmdFrame	=	13	;XIDCmd
	jmp	lapNRMXCmdValid				;uXIDRspFrame	=	14	;XIDRsp

;********** pl2lapTxValid **********

pl2lapTxComplete
	bank	lapBank
	mov	w, lapState				;Jump based on state
	jmp	PC+w
	jmp	lapNDMTxComplete			; 0 = lapNDMState        (not interesting in TxComplete)
	retp						; 1 = lapQUERYState      (not interesting in TxComplete)
	jmp	lapNDM2NRMTxComplete			; 2 = lapNDM2NRMState    (now can apply connection parameters)
	retp						; 3 = lapNRMState        (not interesting in TxComplete)
	retp						; 4 = lapSCLOSEState     (not interesting in TxComplete)
	jmp	lapSCLOSE2NDMTxComplete			; 5 = lapSCLOSE2NDMState (now can apply defaultconnection parameters)

;********** fl2lapMediaBusy **********

fl2lapMediaBusy
	bank	lapBank
	cse	lapState, #lapNDMState			;NDM state ?
	retp						;No => ignore
	clrb	lapMediaIdle				;Clear MediaIdle flag
	test	lapRxFrame				;Is a frame being received ?
	sz
	retp						;Yes => do not reset timer
	mov	w, #Timer570ms				;No  => Reset timer to 500ms
	jmp	lapSetTimer				;Apply timer to wait for media idle

;********** DiscoveryRequest **********

app2lapDiscoveryRequest
	bank	lapBank
	cse	lapState, #lapNDMState			;NDM state ?
	clrb	lapMediaIdle				;No  => same as MediaIdle being false
	stz						;Indicate busy
	sb	lapMediaIdle				;Is the media idle ?
	retp						;No  => return busy indication
	bank	plBank
	mov	plConnAddr, #$FE			;Accept broadcast replys only
	bank	lapBank
	clr	lapTxXIDSlot				;Start at slot # 0
	mov	lapState, #lapQUERYState		;Enter QUERY state
	call	:Send					;Send first frame
	clz						;Indicate request was accepted
	retp
:Send	jmp	lapQUERYTimer

;********** DiscoveryRequest **********

app2lapTxUIStart
	bank	lapBank
	cse	lapState, #lapNDMState			;NDM state ?
	clrb	lapMediaIdle				;No  => same as MediaIdle being false
	stz						;Indicate busy
	sb	lapMediaIdle				;Is the media idle ?
	retp						;No  => return busy indication
	clrb	lapMediaIdle				;Remember that another frame cannot be sent
	setb	lapRxUIDataFlag				;Flag to pass messages to app layer
	call	@lap2plTxUICmd				;Request that the payload layer send a UI command frame
	clz						;Indicate request was accepted
	retp

;********************************************************************************
;  LAP LAYER - Internal Subroutines
;********************************************************************************

lapRandomFlags	=	Temp+0
lapRandomMask	=	Temp+1

;Slot bits: %00 =>  1 slot  => Mask = %0000 = 0 -> 0
;           %01 =>  6 slots => Mask = %0011 = 0 -> 3 (ie can't result in 4 or 5)
;           %10 =>  8 slots => Mask = %0111 = 0 -> 7
;           %11 => 16 slots => Mask = %1111 = 0 -> 15

lapRandomSlot						;returns Slot number to transmit in
	bank	plBank					;Peek at frame info
	mov	w, plXIDFlags				;get discovery flags
	bank	lapBank
	and	w, #%00000011				;Mask out non Slot bits
	snz						;Slot bits = 0 ?
	retp						;Yes => return 0
	mov	lapRandomFlags, w			;Store into Flags register
	mov	w, #%00000001				;If bit 1 = 0 then w = 0001
	snb	lapRandomFlags.1
	mov	w, #%00000111				;If bit 1 = 1 then w = 0111
	mov	lapRandomMask, w			;Mask = 0001 or 0111
	stc
	snb	lapRandomFlags.0			;If bit 0 = 1 then rotate left with carry set
	rl	lapRandomMask				;Rotate mask with carry set
	bank	TimerBank
	mov	w, Random				;random number (non resetable, increments every timer interrupt)
	bank	lapBank					;Note: The code is synchronous with RTCC and so RTCC is not a random number
	and	w, lapRandomMask			;Mask out unwanted bits
	mov	lapTxXIDSlot, w				;Store slot number
	retp

;********** SetTimer **********

lapSetTimer						;w = negative number to count up from
	bank	TimerBank				;-1 = 141.56ms
	clr	Timer1
	clr	Timer2
	mov	Timer3, w
	clrb	TimerOverflow
	bank	lapBank
	retp

;********** fl2lapMediaBusy **********

lapMediaBusy
	clr	lapRxFrame				;Reset frame type to none
	mov	w, #Timer570ms				;No  => Reset timer to 500ms
	jmp	lapSetTimer				;Apply timer to wait for media idle

;********************************************************************************
;  LAP LAYER
;********************************************************************************

;********** pl2lapRxError **********

pl2lapRxError
	bank	lapBank
	call	lapMediaBusy				;Reset media idle detection
	snb	laplmpRxFlag				;Has the lmp layer been receiving data ?
	jmp	:LMP					;Yes => must inform lmp layer
	snb	lapXIDDataFlag				;Has the host been informed to expect XID data ?
	jmp	:XID					;Yes => inform of error
	sb	lapRxUIDataFlag				;Is the app layer expecting data
	retp						;No  => return
:UI	clrb	lapRxUIDataFlag				;Yes => Inform app layer that UI frame is invalid
	jmp	@lap2appRxUIError
:LMP	clrb	laplmpRxFlag				;Clear flag
	jmp	@lap2lmpRxError				;Inform lmp layer of error (lmp layer will issue ret instruction)
:XID	clrb	lapXIDDataFlag				;Clear flag
	debugl	ShowXIDInfo, '}'			;Inform host of error
	retp


;********** pl2lapRxXIDData **********

pl2lapRxXIDData
	bank	lapBank
	sb	lapXIDDataFlag				;Is the host expecting XID Data ?
	retp						;No  => ignore data
	debug	ShowXIDInfo				;Yes => pass data
	retp

;********** pl2lapRxIData **********

pl2lapRxIData
	bank	lapBank
	sb	laplmpRxFlag				;Should we pass data ?
	retp						;No  => ignore data
	jmp	@lap2lmpRxData				;Yes => pass data

;********** pl2lapTxIData **********

pl2lapTxIData
	jmp	@lap2lmpTxData				;Get data from lmp layer

;********** pl2lapRxUIData **********

pl2lapRxUIData
	bank	lapBank
	sb	lapRxUIDataFlag				;Should we pass data ?
	retp						;No  => ignore data
	jmp	@lap2appRxUIData			;Yes => pass data

;********** pl2lapTxUIData **********

pl2lapTxUIData
	jmp	@lap2appTxUIData			;Get data from app layer

;********************************************************************************
;  LAP LAYER - NDM Events
;********************************************************************************

lapEnterNDMState					;Reset connection parameters
	mov	lapState, #lapNDMState			;Enter NDM state
	call	lapMediaBusy				;Reset media idle detection
:Tx	sb	laplmpTxFlag				;Is the lmp data waiting for comformation of data ?
	jmp	:Rx					;No  => contiue without message to lmp layer
	clrb	laplmpTxFlag				;Yes => inform lap layer that data was not-acknowledged and contiue
	call	@lap2lmpTxError
	bank	lapBank
:Rx	sb	lapLmpRxFlag				;Is the lmp layer expecting data ?
	jmp	:Cont					;No  => contiue without message to lmp layer
	clrb	lapLmpRxFlag				;Yes => must inform lmp layer that data is invalid
	call	@lap2lmpRxError
:Cont	bank	plBank
	mov	plConnAddr, #$FF			;Not connected => set ConnAddr to only accept be $FF
	bank	flBank
	mov	flFFCount, #10				;Default to 10 FFs @ 9600 = 10.42ms
	bank	IsrBank
	mov	IrdaSpeed, #Irda9600			;IrDA UART speed = 9600
	clrb	ledCON					;Turn off Connect LED
	debugl	ShowConnect, ']'
	jmp	@lap2lmpDisconnectIndication		;Inform lmp layer of disconnection

;********** NDM - RxFrame **********

lapNDMRxFrame
	csne	lapRxFrame, #uXIDCmdFrame		;XID Command frame ?
	jmp	:Accept					;Yes => Accept frame (may want to code to inform host of incommming XIDCmd frame ?)
	csne	lapRxFrame, #uNRMFrame			;SNRM Command frame ?
	jmp	:Accept					;Yes => Accept frame
	csne	lapRxFrame, #uUIFrame			;UI frame ?
	jmp	:UI					;Yes => Accept frame
	clr	lapRxFrame				;No  => Ignore frame
	jmp	@lap2plRxIgnore				;Request that the payload layer ignores the frame
:UI	setb	lapRxUIDataFlag				;Flag to pass data to app layer
:Accept	mov	w, #Timer570ms				;500ms Timeout
	jmp	lapSetTimer				;(lapSetTimer will issue retp instruction)

;********** NDM - Timer **********

lapNDMTimer
	test	lapRxFrame				;Was a frame being received ?
	jnz	pl2lapRxError				;Yes => treat as error, pl2lapRxError will reset the MediaBusy detection
	setb	lapMediaIdle				;No  => media must be idle
	retp

;********** NDM - RxValid **********

lapNDMRxValid
	csne	lapRxFrame, #uXIDCmdFrame		;XID Command frame ?
	jmp	:XID					;Yes => process
	csne	lapRxFrame, #uNRMFrame			;SNRM Command frame ?
	jmp	:SNRM					;Yes => process
							;No  => must be UI frame
:UI	call	lapMediaBusy				;Reset media idle detection
	sb	lapRxUIDataFlag				;Is the app layer expecting data
	retp						;No =>  ignore
	clrb	lapRxUIDataFlag				;Yes => Inform app layer that UI frame is complete
	jmp	@lap2appRxUIValid

:XID	call	lapMediaBusy				;Reset media idle detection
	bank	plBank					;Peek at frame info
	snb	plXIDFlags.2				;Is the "Generate new device address" flag set ?
	call	@lap2plGenerateNewAddr			;Yes => ask payload layer to generate a new 32-bit address
	bank	plBank					;Peek at frame info
	test	plXIDSlot				;is the slot number = 0 ?
	bank	lapBank
	snz
	call	lapRandomSlot				;Yes => generate random slot (slot returned in lapTxXIDSlot)
	mov	w, lapTxXIDSlot				;Get the slot number to transmit in
	bank	plBank
	mov	w, plXIDSlot-w				;Subtract (ie compare) with current slot number
	sz						;Are they the same ? (ie this slot to transmit in ?)
	retp						;No  => return
	bank	lapBank
	mov	w, lapTxXIDSlot
	clr	lapTxXIDSlot				;Reset slot number to indicate that a reply has been sent
	jmp	@lap2plTxXIDRsp				;Transmit response

:SNRM	mov	lapState, #lapNDM2NRMState		;Next state wil be NDM2NRM state to apply connection parameters after this reply has been sent
	clrb	lapRemoteBusy				;Initilise RemoteBusy flag to false
	clr	lapRxNs					;Initilise RxNs to 0
	clr	lapRxNrAck				;Initilise RxNrAck to zero
	clr	lapRxNrNotAck				;Initilise RxNrNotAck to zero
	mov	w, #Timer1000ms				;1s timeout IrDA Lite p15)
	call	lapSetTimer
	setb	ledCON					;Turn on Connect LED
	debugl	ShowConnect, '['
	call	@lap2lmpConnectIndication		;Inform lmp layer of connection
	jmp	@lap2plSNRMAccept			;Send reply

;********** NDM - TxComplete **********

lapNDMTxComplete
	call	lapMediaBusy				;Reset media idle test
	sb	lapRxUIDataFlag				;Is the app layer expecting data
	retp						;No =>  ignore
	clrb	lapRxUIDataFlag				;Yes => Inform app layer that UI frame is complete
	jmp	@lap2appTxUIComplete

;********************************************************************************
;  LAP LAYER - QUERY Events
;********************************************************************************

;********** QUERY - RxFrame **********

lapQUERYRxFrame
	cse	lapRxFrame, #uXIDRspFrame		;XID Response frame ?
	jmp	@lap2plRxIgnore				;No  => Ignore frame
	setb	lapXIDDataFlag				;Yes => Accept frame. Remember that currently passing data to host
	debugl	ShowXIDInfo, '{'			;Show XID info start
	retp

;********** QUERY - RxValid **********

lapQUERYRxValid
	sb	lapXIDDataFlag				;Is the host expecting data
	retp						;No =>  ignore
	clrb	lapXIDDataFlag				;Yes => Inform host that XID frame is complete
	debugl	ShowXIDInfo, '}'
	retp

;********** QUERY - Timer **********

lapQUERYTimer
	bank	TimerBank				;Set global timer
	clr	Timer1					;80ms timeout after transmission is complete (75-85ms IrDA Lite p21)
	mov	Timer2, #-198				;80ms timeout + 29.2 ms (28 bytes) to transmit = 109.2ms. 198 : 198*256*108*(1/50MHz) = 109.49ms
	mov	Timer3, #-1				;negitive number
	clrb	TimerOverflow
	bank	lapBank
	sb	lapXIDDataFlag				;Has the host been informed to expect XID data ?
	jmp	:Good					;Yes => inform of error
	clrb	lapXIDDataFlag				;Clear flag
	debugl	ShowXIDInfo, '}'			;Inform host of error
:Good	cse	lapTxXIDSlot, #08			;Last slot ?
	jmp	:Send					;No  => send
	mov	lapState, #lapNDMState			;Yes => After send will return to NDM state
	mov	w, #$FF					;w = FF
	mov	lapTxXIDSlot, w				;set slot to $FF to indicate complete
	bank	plBank
	mov	plConnAddr, w				;ConnAddr = FF => Accept broadcast commands only
	bank	lapBank
:Send	mov	w, lapTxXIDSlot				;Get current slot #
	inc	lapTxXIDSlot				;Increment for nexty slot #
	jmp	@lap2plTxXIDCmd				;Send XID command frame (payload layer will return)

;********************************************************************************
;  LAP LAYER - NRM Events
;********************************************************************************

;********** NDM2NRM - TxComplete **********

lapNDM2NRMTxComplete
	mov	lapState, #lapNRMState			;NRM state
	bank	plBank					;Agreed BaudRate is the most significant bit that is set in plSNRMBaudRate
	mov	w, #Irda9600				;Min = 9600
	snb	plSNRMBaudRate.2			;19200 ?
	mov	w, #Irda19200				;Yes => w = 19200
	snb	plSNRMBaudRate.3			;38400 ?
	mov	w, #Irda38400				;Yes => w = 38400
	snb	plSNRMBaudRate.4			;57600 ?
	mov	w, #Irda57600				;Yes => w = 57600
	snb	plSNRMBaudRate.5			;115200 ?
	mov	w, #Irda115200				;Yes => w = 115200
	bank	IsrBank
	mov	IrdaSpeed, w				;Apply baud rate
	bank	plBank					;Set FF Count to ensure 10ms. FFCount = BaudRate / 10 * 0.01s
	mov	w, #lapMinTurnaround / 11.6		;Min = 9600 => 10ms = 10 bytes
	snb	plSNRMBaudRate.2			;19200 ?
	mov	w, #lapMinTurnaround / 5.8		;Yes => 10ms = 20 bytes
	snb	plSNRMBaudRate.3			;38400 ?
	mov	w, #lapMinTurnaround / 2.9		;Yes => 10ms = 39 bytes
	snb	plSNRMBaudRate.4			;57600 ?
	mov	w, #lapMinTurnaround / 2		;Yes => 10ms = 58 bytes
	snb	plSNRMBaudRate.5			;115200 ?
	mov	w, #lapMinTurnaround			;Yes => 10ms = 116 bytes
	bank	flBank
	mov	flFFCount, w				;Apply FFCount
	retp

;********** NRM - SendResponse **********

lapSendNRMResponse
	snb	lapRemoteBusy				;Is the remote busy flag set ?
	jmp	lapSendSResponse			;Yes => send S-Response
	call	@lap2lmpTxFrame				;Returns z = false if data to be sent
	bank	lapBank
	snz						;Is there data to be sent ?
	jmp	lapSendSResponse			;No  => send S-Response
:Data	setb	laplmpTxFlag				;Yes => Rember that lmp layer is passing data
	mov	w, <<lapRxNs				;Send Nr = RxNs. w = RxNs %....nnn.
	and	w, #%00001110				;mask out non Ns bits
	mov	Temp, w					;Store in Temp
	swap	Temp					;Temp = RxNs %nnn.....
	setb	Temp.4					;Set bit 4 = final flag
	mov	w, <<lapRxNrAck				;Send Ns = RxNrAck. w = RxNrAck %....nnn.
	and	w, #%00001110				;mask out non Ns bits
	add	w, Temp					;Add Nr bits
	inc	lapRxNrAck				;add 1 to NrAck - the expect acknowledge
	jmp	@lap2plTxIRsp				;Transmit I frame
	
lapSendSResponse
	mov	w, <<lapRxNs				;Send Nr = RxNs. w = RxNs %....nnn.
	and	w, #%00001110				;mask out non Ns bits
	mov	Temp, w					;Store in Temp
	swap	Temp					;Temp = RxNs %nnn.....
	mov	w, #sRR					;frame will be of type RR
	add	w, Temp					;Set Nr of frame to RxNs = expected next I frame
	jmp	@lap2plTxSimpleRsp			;Send simple response frame

;********** NRM - SendRD **********

lapNRMSendRD
	mov	w, #Timer3000ms
	call	lapSetTimer				;Reset timer for SCLOSE state
	sb	lapLmpRxFlag				;Is the lmp layer expecting data ? (ie error caused by timeout)
	jmp	:Cont					;No  => contiue
	clrb	lapLmpRxFlag				;Yes => must inform lmp layer that data is invalid
	call	@lap2lmpRxError				;
	bank	lapBank
:Cont	mov	lapState, #lapSCLOSEState		;change to SCLOSE state
	mov	w, #uRDRsp				;frame will be of type RD
	jmp	@lap2plTxSimpleRsp			;Send simple response frame

;********** NRM - RxFrame **********

lapNRMRxFrame
	csne	lapRxFrame, #iFrame			;I Data frame ?
	setb	lapLmpRxFlag				;Yes => Flag to pass data to lmp layer
	retp						;Accept all frames

;********** NRM - SValid or IValid **********

lapNRMSIValid
	mov	w, #Timer3000ms
	call	lapSetTimer				;Reset timer on any S-Command
	bank	plBank
	mov	w, >>plCommand				;w = %.nnn.... get the received command byte (shifted)
	mov	Temp, w					;Temp = received Nr bits (%.nnn....)
	swap	Temp					;Temp = received Nr bits (%.....nnn)
	bank	lapBank
	mov	w, lapRxNrAck				;w = expected Nr if Ack
	xor	w, Temp					;compare received Nr with NrAck
	and	w, #%00000111				;only examine lowest bits
	snz						;Does Nr = NrAck (ie is this a valid ack) ?
	jmp	:Ack					;Yes => valid Ack
	mov	w, lapRxNrNotAck			;w = expected Nr if Not-Ack
	xor	w, Temp					;compare received Nr with NrNotAck
	and	w, #%00000111				;only examine lostest bits
	sz						;Does Nr = NrNotAck (ie is this a valid not-ack) ?
	jmp	lapNRMSendRD				;No  => Fatal Error - invalid Nr => must disconnect (Valid/Error message for LMP layer willbe sent prior to the DisconnectIndication)
:NotAck	dec	lapRxNrAck				;return NrAck back to what it was before transmission of the last I-Frame
	sb	laplmpTxFlag				;Is the lmp data waiting for comformation of data ?
	jmp	:Cont					;No  => contiue without message to lmp layer
	clrb	laplmpTxFlag				;Yes => inform lap layer that data was not-acknowledged and contiue
	call	@lap2lmpTxError
	jmp	:Cont
:Ack	mov	lapRxNrNotAck, lapRxNrAck		;Set NrNotAck to match NrAck
	sb	laplmpTxFlag				;Is the lmp data waiting for comformation of data ?
	jmp	:Cont					;No  => contiue without message to lmp layer
	clrb	laplmpTxFlag				;Yes => inform lap layer that data was acknowledged and contiue
	call	@lap2lmpTxValid
:Cont	bank	lapBank
	cse	lapRxFrame, #iFrame			;Is this an i frame ?
	jmp	lapSendNRMResponse			;No  => S frame => Send-NRM-Response
	bank	plBank					;Yes => must test Ns
	mov	w, >>plCommand				;get the received command byte (shifted right 1 bit)
	bank	lapBank
	xor	w, lapRxNs				;Compare with expected Ns
	and	w, #%00000111				;Only test lowest 3 bits
	jnz	:Ignore					;If Ns <> expected then ignore
:Valid	inc	lapRxNs					;increment RxNs
	sb	lapLmpRxFlag				;Is the lmp layer expecting data ?
	jmp	lapSendNRMResponse			;No  => send NRM-response
	clrb	lapLmpRxFlag				;Yes => must inform lmp layer that data is complete
	call	@lap2lmpRxValid				;Indicate data complete and valid
	bank	lapBank
	jmp	lapSendNRMResponse			;send NRM-response
:Ignore	sb	lapLmpRxFlag				;Is the lmp layer expecting data ?
	jmp	lapSendSResponse			;No  => send S-response
	clrb	lapLmpRxFlag				;Yes => must inform lmp layer that data is invalid
	call	@lap2lmpRxError				;
	bank	lapBank
	jmp	lapSendSResponse			;send S-response

lapNRMIValid	=	lapNRMSIValid			;A I frame has been received

lapNRMRRValid						;A RR frame has been received
	clrb	lapRemoteBusy				;Remember that remote is not busy and send reply
	jmp	lapNRMSIValid

lapNRMRNRValid						;A RNR frame has been received
	setb	lapRemoteBusy				;Remember that remote is busy and send reply
	jmp	lapNRMSIValid

lapNRMREJValid	=	lapNRMSIValid		;A REJ frame has been received
lapNRMSREJValid	=	lapNRMSIValid		;A SREJ frame has been received

;********** NRM - SNRMCmdValid **********

lapNRMNRMValid	=	lapNRMSendRD

;********** NRM - XCmdValid **********

lapNRMXCmdValid	=	lapSendSResponse

;********** NRM - DISCCmdValid **********

lapNRMDISCValid						;Disconnect command: ack and apply default parameters.
	mov	lapState, #lapSCLOSE2NDMState		;Next state = transition to apply origional connection parameters once this frame has been sent
	mov	w, #uUARsp				;Send UA frame to acknowledge disconnect
	jmp	@lap2plTxSimpleRsp			;Send simple response frame

;********** NRM - Timer **********

lapNRMTimer	=	lapEnterNDMState		;Timeout => return to NDM state.

;********** lmp2lapDisconnectRequestr **********

lmp2lapDisconnectRequest
	bank	lapBank
	cse	lapState, #lapNRMState			;Currenly in NRM state ?
	retp						;No  => ignore request
	mov	lapState, #lapSCLOSEState		;Yes => change to SCLOSE state
	retp

;********************************************************************************
;  LAP LAYER - NRM Events
;********************************************************************************

;********** SCLOSE - RxFrame **********

lapSCLOSERxFrame
	retp						;Accept all frames

;********** SCLOSE - RxValid **********

lapSCLOSERxValid
	csne	lapRxFrame, #uDISCFrame			;DISC Command frame ?
	jmp	lapNRMDISCValid				;Yes => Send ack, apply default parameters and enter NDM state
	mov	w, #Timer3000ms
	call	lapSetTimer				;No, however still must be a command frame (due to ConnAddr) => send RD frame
	mov	w, #uRDRsp				;Send RD Response frame to request disconnect
	jmp	@lap2plTxSimpleRsp			;Send simple response frame

;********** SCLOSE - Timer **********

lapSCLOSETimer		=	lapEnterNDMState

;********** SCLOSE2NDM - TxComplete **********

lapSCLOSE2NDMTxComplete	=	lapEnterNDMState

;********************************************************************************
		ENDM

  .