//J A S M I N E  C A L I B R A T E

get "bcpl.head"

//outgoing procedures
external JasmineCalibrate

//incoming procedures
external 
 [	JasmineLoadRam
	JasmineCoord
	JasmineScanInit
	JasmineReadLine
	JasmineSetDelay	//(delay=0 to 15)
	JasmineSetTime	//(ticks = 38usecond units)
	JasmineSetResolution	//(skips=0 to 15)
	JasmineSetReadMode	//readOnly=1, readAndStep=2, readStepAndDelay=3
	JasmineSetWindow
	JasmineScanClose

	//from GP
	SetupReadParam;ReadParam

	//from PressML
	MulFull;DoubleAddV;MulDiv;DoubleShr
 ]


structure Array :
 [ pixel^0,1000	byte
 ]

structure JasmineRam :
 [	blank	bit 4
	Offset	bit 6
	Gain	bit 6
 ]

manifest ArraySize = 1024	

static
 [	nAverages=8;
	A=7;B=8	//threshold for page edge detection
	mulA=4;mulB=3 //factor for setting gain multiplier
 ]

//calibrate routine returns a block with:
//	xstart,xlen of page
//	min,max for 656 time, skip 0
//	min,max for 219 time, skip 1
let JasmineCalibrate() = valof
 [	let resultThingy = table [ 0;0;0;0;0;0]
	let saved420=@#420
	@#420=@saved420
	let ramvals = vec ArraySize
	let block=vec 512*4
	let targetGain=0;let targetOffset=0
	let ramVal=0;
	ramVal<<JasmineRam.Offset=64-10//targetOffset
	ramVal<<JasmineRam.Gain=targetGain
	SetBlock(ramvals,ramVal,ArraySize)

	JasmineLoadRam(ramvals,ArraySize)
	JasmineSetDelay(15)
	JasmineSetResolution(0)
	JasmineSetTime(656)	//1/40 sec

	let inputArray=vec ArraySize
	let min,max=nil,nil

	let lastCorrection=0
	JasmineSetWindow(0,1024,100,300)
	JasmineSetReadMode(3)	//read, step, and delay (for constant integration time)
	[ //white repeat loop
	let scanHead = JasmineScanInit(block,512*4)
for i=1 to 4 do JasmineReadLine(scanHead) //first few lines seem to be garbage...
	Zero(inputArray,ArraySize)
	for average=1 to nAverages do
	 [	let scanLine=JasmineReadLine(scanHead)
		for x=0 to ArraySize-1 do
			inputArray!x=inputArray!x+scanLine>>Array.pixel^x
	 ]
	JasmineScanClose(scanHead)
	max=0;min=256
	for x=0 to ArraySize-2 do	//-2 for Prom bug 
	 [	let val=(inputArray!x)/nAverages
		inputArray!x=val
		if val ls min then min=val
		if val gr max then max=val
	 ]
	Ws("Min: ");Wns(dsp,min);Ws("  Max: ");Wns(dsp,max)
	if targetGain eq 0 then targetGain=max
	let newCorrection=0
	for x=0 to ArraySize-1 do
	 [	let currentVal=(ramvals!x)<<JasmineRam.Gain
		let correction=targetGain - inputArray!x
		if inputArray!x ls 10 then correction=correction-256//wrap around
		if correction ls 100 then newCorrection=newCorrection+abs(correction)
		let newVal=currentVal + (correction*mulA)/mulB
		if newVal ls 0 then newVal=0
		if newVal gr 63 then newVal=63
		(ramvals!x)<<JasmineRam.Gain=newVal
	 ]
	Ws(" [");Wns(dsp,newCorrection);Ws("] ")
	if (lastCorrection ne 0)&(newCorrection gr lastCorrection) then break
	JasmineLoadRam(ramvals,ArraySize)

	lastCorrection=newCorrection
	] repeat	//white repeat loop

//now, calculate xstart, xend for 8.5 inches
let thresh = min + ((max-min)*A)/B
for x=1 to 1000 do if inputArray!x gr thresh then [ resultThingy!0=x;break]
for x=1000 to 1 by -1 do if inputArray!x gr thresh then
		[ resultThingy!1=x-resultThingy!0;break]
resultThingy!2=min
resultThingy!3=max
//and high speed chase
JasmineSetDelay(4)
JasmineSetResolution(1)
JasmineSetTime(219)
let scanHead = JasmineScanInit(block,512*4)
for i=1 to 20 do JasmineReadLine(scanHead)
min=256;max=0
inputArray=JasmineReadLine(scanHead)
	JasmineScanClose(scanHead)
	for x=1 to 500 do 
	 [	let val=inputArray>>Array.pixel^x
		if val ls min then min=val
		if val gr max then max=val
	 ]
JasmineSetDelay(15)
JasmineSetResolution(0)
JasmineSetTime(656)
JasmineSetReadMode(2)
resultThingy!4=min
resultThingy!5=max
	@#420=saved420
resultis resultThingy
]

and abs(x)=(x ge 0)?x,-x

(635)\1614b81B