--- a/src/calibrate.asm	Thu Oct 11 21:06:29 2018 +0200
+++ b/src/calibrate.asm	Thu Nov 22 19:47:26 2018 +0100
@@ -1,6 +1,6 @@
 ;=============================================================================
 ;
-;   File calibration.asm							REFACTORED VERSION V2.98
+;   File calibration.asm							REFACTORED VERSION V2.98b
 ;
 ;   o2 sensor calibration subroutines
 ;
@@ -8,209 +8,180 @@
 ;=============================================================================
 
 #include "hwos.inc"
-#include "shared_definitions.h"				; Mailbox between c and asm
+#include "shared_definitions.h"				; mailbox between c and asm
 #include "math.inc"
 #include "adc_lightsensor.inc"
 #include "eeprom_rs232.inc"
+#include "isr.inc"	
 
 
 calibrate	CODE
 
-	global	check_sensors					; Check O2 sensor thresholds for fallback and voting logic
-check_sensors:
-	; Check min_mv
-	movff	o2_mv_sensor1+0, sub_a+0
-	movff	o2_mv_sensor1+1, sub_a+1
-	movlw	LOW  min_mv
-	movwf	sub_b+0
-	movlw	HIGH min_mv
-	movwf	sub_b+1
-	call	sub16							; sub_c = sub_a - sub_b
-	bsf		use_O2_sensor1					;=1: Use this sensor for deco
-	btfsc	neg_flag
-	bcf		use_O2_sensor1					;=1: Use this sensor for deco
+
+	global	transmit_setpoint				; transmit current setpoint from WREG (in cbar) to external electronics
+transmit_setpoint:
+	return									; 					!!!! FUNCTION IS CURRENTLY DISABLED !!!!
+	btfss	s8_digital						; S8 Digital connection existing?
+	return									; NO  - ignore
+											; YES - transmit setpoint from WREG
+	clrf	lo								; initialize checksum
+	movwf	hi								; store setpoint
+	movlw	0xAA							; start byte
+	rcall	tx_to_HUD						; transmit to HUD
+	movlw	0x60							; command new SP
+	rcall	tx_to_HUD						; transmit to HUD
+	movff	hi,WREG							; SP in cbar
+	rcall	tx_to_HUD						; transmit to HUD
+	movff	lo,WREG							; checksum
+	rcall	tx_to_HUD_cs					; transmit checksum
+	return
+
+tx_to_HUD:									; entry point to transmit a byte to the HUD
+	addwf	lo,F							; add byte to checksum
+tx_to_HUD_cs:								; entry point to transmit the checksum
+	movff	WREG,TXREG2						; transmit byte
+	call	rs232_wait_tx2					; wait for UART
+	return
+
 
-	movff	o2_mv_sensor2+0, sub_a+0
-	movff	o2_mv_sensor2+1, sub_a+1
-	movlw	LOW  min_mv
-	movwf	sub_b+0
-	movlw	HIGH min_mv
-	movwf	sub_b+1
-	call	sub16							; sub_c = sub_a - sub_b
-	bsf		use_O2_sensor2					;=1: Use this sensor for deco
-	btfsc	neg_flag
-	bcf		use_O2_sensor2					;=1: Use this sensor for deco
+	global	calibrate_mix
+calibrate_mix:
+	; set usage and calibration flags as per default
+	bsf		use_O2_sensor1
+	bsf		use_O2_sensor2
+	bsf		use_O2_sensor3
+	bsf		sensor1_calibrated_ok
+	bsf		sensor2_calibrated_ok
+	bsf		sensor3_calibrated_ok
+
+	; check for HUD
+	btfss	s8_digital						; S8 Digital connection existing?
+	bra		calibrate_mix1					; NO  - skip HUD part
 
-	movff	o2_mv_sensor3+0, sub_a+0
-	movff	o2_mv_sensor3+1, sub_a+1
-	movlw	LOW  min_mv
-	movwf	sub_b+0
-	movlw	HIGH min_mv
-	movwf	sub_b+1
-	call	sub16							; sub_c = sub_a - sub_b
-	bsf		use_O2_sensor3					;=1: Use this sensor for deco
-	btfsc	neg_flag
-	bcf		use_O2_sensor3					;=1: Use this sensor for deco
+	; calibrate any S8-connected HUD
+	clrf	lo								; initialize checksum
+	movlw	0xAA							; start byte
+	rcall	tx_to_HUD						; transmit to HUD
+	movlw	0x31							; calibration command
+	rcall	tx_to_HUD						; transmit to HUD
+	movff	opt_calibration_O2_ratio,WREG	; calibration gas %O2
+	rcall	tx_to_HUD						; transmit to HUD
+	movff	amb_pressure+0,WREG				; ambient pressure low byte
+	rcall	tx_to_HUD						; transmit to HUD
+	movff	amb_pressure+1,WREG				; ambient pressure high byte
+	rcall	tx_to_HUD						; transmit to HUD
+	movff	lo,WREG							; checksum
+	rcall	tx_to_HUD_cs					; transmit to HUD
+;	bra		calibrate_mix2
 
-	; Check max_mv
-	movff	o2_mv_sensor1+0, sub_a+0
+	; calibrate internal sensors
+calibrate_mix1:								; compute %O2 * 100 * ambient_pressure[mbar] / 100
+	movff	opt_calibration_O2_ratio,WREG
+	mullw	.100
+	movff	PRODL,xA+0
+	movff	PRODH,xA+1
+	SAFE_2BYTE_COPY amb_pressure,xB 
+	call	mult16x16						; xA*xB=xC
+	movlw	LOW  .100
+	movwf	xB+0
+	movlw	HIGH .100
+	movwf	xB+1
+	call	div32x16						; xC:4 / xB:2 = xC+3:xC+2 with xC+1:xC+0 as remainder
+
+	; keep a copy of the result
+	movff	xC+0,lo
+	movff	xC+1,hi
+	movff	xC+2,up
+	movff	xC+3,ex
+
+	; compute factor for sensor 1
+	movff	o2_mv_sensor1+0,xB+0
+	movff	o2_mv_sensor1+1,xB+1
+	call	div32x16						; xC:4 / xB:2 = xC+3:xC+2 with xC+1:xC+0 as remainder
+	movff	xC+0,opt_x_s1+0					; xC= ppO2/mV as factor for sensor 1
+	movff	xC+1,opt_x_s1+1
+
+	; restore result
+	movff	lo,xC+0
+	movff	hi,xC+1
+	movff	up,xC+2
+	movff	ex,xC+3
+
+	; compute factor for sensor 2
+	movff	o2_mv_sensor2+0,xB+0
+	movff	o2_mv_sensor2+1,xB+1
+	call	div32x16						; xC:4 / xB:2 = xC+3:xC+2 with xC+1:xC+0 as remainder
+	movff	xC+0,opt_x_s2+0					; xC= ppO2/mV as factor for sensor 2
+	movff	xC+1,opt_x_s2+1
+
+	; restore result
+	movff	lo,xC+0
+	movff	hi,xC+1
+	movff	up,xC+2
+	movff	ex,xC+3
+
+	; compute factor for sensor 3
+	movff	o2_mv_sensor3+0,xB+0
+	movff	o2_mv_sensor3+1,xB+1
+	call	div32x16						; xC:4 / xB:2 = xC+3:xC+2 with xC+1:xC+0 as remainder
+	movff	xC+0,opt_x_s3+0					; xC= ppO2/mV as factor for sensor 3
+	movff	xC+1,opt_x_s3+1
+
+	; check sensor 1 for min/max mV
+	movff	o2_mv_sensor1+0, sub_a+0		; get mV from sensor 1
 	movff	o2_mv_sensor1+1, sub_a+1
-	movlw	LOW  max_mv
-	movwf	sub_b+0
-	movlw	HIGH max_mv
-	movwf	sub_b+1
-	call	sub16							; sub_c = sub_a - sub_b
-	btfss	neg_flag
-	bcf		use_O2_sensor1					;=1: Use this sensor for deco
+	rcall	calibrate_mix_helper			; check mV for min/max thresholds, returns with WREG = 0 if ok, else WREG = 1
+	TSTFSZ	WREG							; sensor mV within thresholds?
+	bcf		use_O2_sensor1					; NO - clear usage flag
 
-	movff	o2_mv_sensor2+0, sub_a+0
+	; check sensor 2 for min/max mV
+	movff	o2_mv_sensor2+0, sub_a+0		; get mV from sensor 2
 	movff	o2_mv_sensor2+1, sub_a+1
-	movlw	LOW  max_mv
-	movwf	sub_b+0
-	movlw	HIGH max_mv
-	movwf	sub_b+1
-	call	sub16							; sub_c = sub_a - sub_b
-	btfss	neg_flag
-	bcf		use_O2_sensor2					;=1: Use this sensor for deco
+	rcall	calibrate_mix_helper			; check mV for min/max thresholds, returns with WREG = 0 if ok, else WREG = 1
+	TSTFSZ	WREG							; sensor mV within thresholds?
+	bcf		use_O2_sensor2					; NO - clear usage flag
 
-	movff	o2_mv_sensor3+0, sub_a+0
+	; check sensor 3 for min/max mV
+	movff	o2_mv_sensor3+0, sub_a+0		; get mV from sensor 3
 	movff	o2_mv_sensor3+1, sub_a+1
-	movlw	LOW  max_mv
-	movwf	sub_b+0
-	movlw	HIGH max_mv
-	movwf	sub_b+1
-	call	sub16							; sub_c = sub_a - sub_b
-	btfss	neg_flag
-	bcf		use_O2_sensor3					;=1: Use this sensor for deco
+	rcall	calibrate_mix_helper			; check mV for min/max thresholds, returns with WREG = 0 if ok, else WREG = 1
+	TSTFSZ	WREG							; sensor mV within thresholds?
+	bcf		use_O2_sensor3					; NO - clear usage flag
 
-	btfss	hud_connection_ok				;=1: HUD connection ok
-	bra		check_sensor2					; No HUD/Digital data
+calibrate_mix2:
+	; check for HUD
+	btfss	hud_connection_ok				; HUD connection existing?
+	bra		calibrate_mix3					; NO - skip HUD part
 
-	; Copy disable flags from digital input
+	; Copy disable flags from HUD digital input
 	btfss	sensor1_active
 	bcf		use_O2_sensor1
 	btfss	sensor2_active
 	bcf		use_O2_sensor2
 	btfss	sensor3_active
 	bcf		use_O2_sensor3
-	return
-
-check_sensor2:
-	; Copy disable flags from internal calibration routine
-	btfss	sensor1_calibrated_ok
-	bcf		use_O2_sensor1
-	btfss	sensor2_calibrated_ok
-	bcf		use_O2_sensor2
-	btfss	sensor3_calibrated_ok
-	bcf		use_O2_sensor3
-	return
-
-
-	global	calibrate_mix
-calibrate_mix:
-	; calibrate S8 HUD
-	btfss	s8_digital						; S8 Digital?
-	bra		calibrate_mix2					; No
-
-	; Yes, calibrate any S8-connected HUD
-	clrf	lo								; Checksum
-	movlw	0xAA							; Start Byte
-	addwf	lo,F
-	movff	WREG,TXREG2
-	call	rs232_wait_tx2
-
-	movlw	0x31							; Calibrate
-	addwf	lo,F
-	movff	WREG,TXREG2
-	call	rs232_wait_tx2
-
-	movff	opt_calibration_O2_ratio,WREG	; Calibration gas %O2
-	addwf	lo,F
-	movff	WREG,TXREG2
-	call	rs232_wait_tx2
-
-	movff	amb_pressure+0,WREG				; Ambient pressure
-	addwf	lo,F
-	movff	WREG,TXREG2
-	call	rs232_wait_tx2
-	movff	amb_pressure+1,WREG
-	addwf	lo,F
-	movff	WREG,TXREG2
-	call	rs232_wait_tx2
-
-	movff	lo,TXREG2						; Checksum
-	call	rs232_wait_tx2
 
-calibrate_mix2:
-	movff	opt_calibration_O2_ratio,WREG	; Calibration gas %O2
-	mullw	.100
-	movff	PRODL,xA+0
-	movff	PRODH,xA+1
-	; (%O2*100)*[ambient,mbar]/100 -> xC
-	movff	amb_pressure+0,xB+0
-	movff	amb_pressure+1,xB+1
-	rcall	calibrate_mix2_helper
-	movff	o2_mv_sensor1+0,xB+0
-	movff	o2_mv_sensor1+1,xB+1
-	call	div32x16						; xC:4 / xB:2 = xC+3:xC+2 with xC+1:xC+0 as remainder
-	; xC= ppO2/mV
-	movff	xC+0,opt_x_s1+0
-	movff	xC+1,opt_x_s1+1					; Factor for Sensor1
+calibrate_mix3:
+	; clear calibration flags if sensors are not found to be ok
+	btfss	use_O2_sensor1					; sensor 1 out of range?
+	bcf		sensor1_calibrated_ok			; YES - disable this sensor
+	btfss	use_O2_sensor2					; sensor 2 out of range?
+	bcf		sensor2_calibrated_ok			; YES - disable this sensor
+	btfss	use_O2_sensor3					; sensor 3 out of range?
+	bcf		sensor3_calibrated_ok			; YES - disable this sensor
 
-	movff	opt_calibration_O2_ratio,WREG	; Calibration gas %O2
-	mullw	.100
-	movff	PRODL,xA+0
-	movff	PRODH,xA+1
-	; (%O2*100)*[ambient,mbar]/100 -> xC
-	movff	amb_pressure+0,xB+0
-	movff	amb_pressure+1,xB+1
-	rcall	calibrate_mix2_helper
-	movff	o2_mv_sensor2+0,xB+0
-	movff	o2_mv_sensor2+1,xB+1
-	call	div32x16						; xC:4 / xB:2 = xC+3:xC+2 with xC+1:xC+0 as remainder
-	; xC= ppO2/mV
-	movff	xC+0,opt_x_s2+0
-	movff	xC+1,opt_x_s2+1					; Factor for Sensor2
-
-	movff	opt_calibration_O2_ratio,WREG	; Calibration gas %O2
-	mullw	.100
-	movff	PRODL,xA+0
-	movff	PRODH,xA+1
-	; (%O2*100)*[ambient,mbar]/100 -> xC
-	movff	amb_pressure+0,xB+0
-	movff	amb_pressure+1,xB+1
-	rcall	calibrate_mix2_helper
-	movff	o2_mv_sensor3+0,xB+0
-	movff	o2_mv_sensor3+1,xB+1
-	call	div32x16						; xC:4 / xB:2 = xC+3:xC+2 with xC+1:xC+0 as remainder
-	; xC= ppO2/mV
-	movff	xC+0,opt_x_s3+0
-	movff	xC+1,opt_x_s3+1					; Factor for Sensor3
-
-	bsf		sensor1_calibrated_ok
-	bsf		sensor2_calibrated_ok
-	bsf		sensor3_calibrated_ok			; Set flags prior check
-
-	rcall	check_sensors					; Check O2 sensor thresholds min_mv and max_mv and set use_02_sensorX flags
-	; initialize internal calibration flags
-	btfss	use_O2_sensor1					; Sensor out of range?
-	bcf		sensor1_calibrated_ok			; Yes, disable this sensor
-	btfss	use_O2_sensor2					; Sensor out of range?
-	bcf		sensor2_calibrated_ok			; Yes, disable this sensor
-	btfss	use_O2_sensor3					; Sensor out of range?
-	bcf		sensor3_calibrated_ok			; Yes, disable this sensor
-
-	; When no sensor is found, enable all three to show error state
+	; When no sensor is found, enable all three to show error state and clear calibration factors
 	btfsc	use_O2_sensor1
 	return
 	btfsc	use_O2_sensor2
 	return
 	btfsc	use_O2_sensor3
 	return
+	; Enable all sensors
 	bsf		use_O2_sensor1
 	bsf		use_O2_sensor2
 	bsf		use_O2_sensor3
-	; Clear factors
+	; Clear calibration factors
 	banksel opt_x_s1+0
 	clrf	opt_x_s1+0
 	clrf	opt_x_s1+1
@@ -221,90 +192,60 @@
 	banksel	common
 	return
 
-
-calibrate_mix2_helper:
-	call	mult16x16						; xA*xB=xC
-	movlw	LOW  .100
-	movwf	xB+0
-	movlw	HIGH .100
-	movwf	xB+1
-	goto	div32x16						; xC:4 / xB:2 = xC+3:xC+2 with xC+1:xC+0 as remainder (And return)
+calibrate_mix_helper:
+	movlw	LOW  min_mv						; load minimum threshold...
+	movwf	sub_b+0							; ...into sub_b
+	movlw	HIGH min_mv
+	movwf	sub_b+1
+	call	sub16							; sub_c = sub_a - sub_b
+	btfsc	neg_flag						; sensor mV lower than minimum threshold?
+	retlw	.1								; YES - return signaling threshold violation
+	movlw	LOW  max_mv						; load maximum threshold...
+	movwf	sub_b+0							; ...into sub_b
+	movlw	HIGH max_mv
+	movwf	sub_b+1
+	call	sub16							; sub_c = sub_a - sub_b
+	btfss	neg_flag						; sensor mV higher than maximum threshold?
+	retlw	.1								; YES - return signaling threshold violation
+	retlw	.0								; NO  - return signaling min/max ok
 
 
 	global	compute_mvolts_for_all_sensors
-compute_mvolts_for_all_sensors:				; Compute mV or all sensors (S8 Mode)
+compute_mvolts_for_all_sensors:				; compute mV or all sensors (S8 mode)
 ; compute AD results in 100µV steps (16bit/sensor)
 ; 24bit AD result is in 244,1406541nV
 ; Divide 24bit value through 409,5999512 -> 410 (0,01% error)
 	#DEFINE	ad2mv_factor .410
+	movlw	LOW  ad2mv_factor
+	movwf	xB+0
+	movlw	HIGH ad2mv_factor
+	movwf	xB+1
 	; Sensor 1
 	clrf	xC+3
 	movff	s8_rawdata_sensor1+2,xC+2
 	movff	s8_rawdata_sensor1+1,xC+1
 	movff	s8_rawdata_sensor1+0,xC+0
-	movlw	LOW  ad2mv_factor
-	movwf	xB+0
-	movlw	HIGH ad2mv_factor
-	movwf	xB+1
 	call	div32x16						; xC:4 / xB:2 = xC+3:xC+2 with xC+1:xC+0 as remainder
 	movff	xC+1,o2_mv_sensor1+1
-	movff	xC+0,o2_mv_sensor1+0			; in 100uV steps
+	movff	xC+0,o2_mv_sensor1+0			; in 100 uV steps
 	; Sensor 2
 	clrf	xC+3
 	movff	s8_rawdata_sensor2+2,xC+2
 	movff	s8_rawdata_sensor2+1,xC+1
 	movff	s8_rawdata_sensor2+0,xC+0
-	movlw	LOW  ad2mv_factor
-	movwf	xB+0
-	movlw	HIGH ad2mv_factor
-	movwf	xB+1
 	call	div32x16						; xC:4 / xB:2 = xC+3:xC+2 with xC+1:xC+0 as remainder
 	movff	xC+1,o2_mv_sensor2+1
-	movff	xC+0,o2_mv_sensor2+0			; in 100uV steps
+	movff	xC+0,o2_mv_sensor2+0			; in 100 uV steps
 	; Sensor 3
 	clrf	xC+3
 	movff	s8_rawdata_sensor3+2,xC+2
 	movff	s8_rawdata_sensor3+1,xC+1
 	movff	s8_rawdata_sensor3+0,xC+0
-	movlw	LOW  ad2mv_factor
-	movwf	xB+0
-	movlw	HIGH ad2mv_factor
-	movwf	xB+1
 	call	div32x16						; xC:4 / xB:2 = xC+3:xC+2 with xC+1:xC+0 as remainder
 	movff	xC+1,o2_mv_sensor3+1
-	movff	xC+0,o2_mv_sensor3+0			; in 100uV steps
-
-	bcf		new_s8_data_available			; Clear flag
-	return									; Done.
-
-
-	global	transmit_setpoint				; Transmit current setpoint from WREG (in cbar) to external electronics
-transmit_setpoint:
-	return									; 					!!!! FUNCTION IS CURRENTLY DISABLED !!!!
-	btfss	s8_digital						; S8 Digital?
-	return									; No, ignore
+	movff	xC+0,o2_mv_sensor3+0			; in 100 uV steps
 
-	; Yes, transmit setpoint from WREG
-	movwf	hi								; Store setpoint
-	clrf	lo								; Checksum
-	movlw	0xAA							; Start Byte
-	addwf	lo,F
-	movff	WREG,TXREG2
-	call	rs232_wait_tx2
-
-	movlw	0x60							; New SP
-	addwf	lo,F
-	movff	WREG,TXREG2
-	call	rs232_wait_tx2
-
-	movff	hi,WREG							; SP in cbar
-	addwf	lo,F
-	movff	WREG,TXREG2
-	call	rs232_wait_tx2
-
-	movff	lo,TXREG2						; Checksum
-	call	rs232_wait_tx2
-	return
-
+	bcf		new_s8_data_available			; clear flag
+	return									; done
 
 	END
\ No newline at end of file