--- a/src/eeprom_rs232.asm	Wed Apr 10 10:51:07 2019 +0200
+++ b/src/eeprom_rs232.asm	Mon Jun 03 14:01:48 2019 +0200
@@ -1,6 +1,6 @@
 ;=============================================================================
 ;
-;   File eeprom_rs232.asm												V2.99a
+;   File eeprom_rs232.asm                     combined next generation V3.03.1
 ;
 ;   Internal EEPROM, RS232
 ;
@@ -14,6 +14,11 @@
 #include "shared_definitions.h"
 #include "rtc.inc"
 
+	extern	lt2942_charge_done
+
+;-----------------------------------------------------------------------------
+; Macros
+
 write_int_eeprom	macro	eeprom_address
 	movlw	eeprom_address
 	call	write_int_eeprom_1
@@ -24,9 +29,10 @@
 	call	read_int_eeprom_1
 	endm
 
-;=============================================================================
-eeprom		code	0xF00000+0x10
-; skip SERIAL number - it should not be overwritten
+;-----------------------------------------------------------------------------
+; Reserved memory locations in EEPROM
+
+eeprom		code	0xF00000+0x10		; skip SERIAL number - it should not be overwritten
 
 	global	eeprom_serial_save
 	global	eeprom_opt_backup
@@ -34,8 +40,11 @@
 eeprom_serial_save	res 2
 eeprom_opt_backup	res 0x3E
 
+;-----------------------------------------------------------------------------
+
+ee_rs232		CODE
+
 ;=============================================================================
-ee_rs232		CODE
 
 	global	write_int_eeprom_1
 write_int_eeprom_1:
@@ -43,16 +52,18 @@
 	bra		write_eeprom				; writes and "returns" after write
 
 
-	global read_int_eeprom_1
+	global	read_int_eeprom_1
 read_int_eeprom_1:
 	movwf	EEADR
 	bra		read_eeprom					; reads and "returns" after write
 
 ;=============================================================================
-; reads from internal EEPROM
+; read from internal EEPROM
+;
 ; Input:   EEADRH:EEADR = EEPROM address
 ; Output:  EEDATA
 ; Trashed: NONE
+;
 	global	read_eeprom
 read_eeprom:
 	bcf		EECON1,EEPGD
@@ -61,10 +72,12 @@
 	return
 
 ;=============================================================================
-; writes into internal EEPROM
+; write into internal EEPROM
+;
 ; Input:   EEADRH:EEADR = EEPROM address
 ;          EEDATA = byte to write
 ; Trashed: WREG
+;
 	global	write_eeprom
 write_eeprom:
 	bcf		EECON1,EEPGD
@@ -85,36 +98,41 @@
 	bcf		EECON1,WREN
 	return
 
+;=============================================================================
+
+ IFDEF _external_sensor
 
 	global	disable_ir_s8
 disable_ir_s8:
-	banksel	TXSTA2
+	banksel	TXSTA2						; select bank for IO register access
 	clrf	TXSTA2
 	clrf	RCSTA2
-	banksel	common
+	banksel	common						; back to bank common
 	bcf		ir_power					; IR off
 	bcf		mcp_power					; power-down instrumentation amp
-	bsf		s8_npower					; power-down S8 HUD
+	bsf		s8_npower					; power-down S8 digital interface
+	bcf		s8_digital_avail			; digital S8 interface not available
 	return
 
 
 	global	enable_ir_s8
 enable_ir_s8:
-;init serial port2 (TRISG2)
-	btfsc	analog_o2_input
-	bra		enable_s8					; start S8
-
-	banksel	BAUDCON2
-	movlw	b'00100000'					; BRG16=0			; inverted for IR
+	;initialize serial port2 (TRISG2)
+	btfsc	analog_o2_input				; do we have an analog input?
+	bra		enable_s8					; YES - search for S8 digital input
+										; NO  - start      IR digital input
+	banksel	BAUDCON2					;     - select bank for IO register access
+	movlw	b'00100000'					;     - BRG16=0, inverted for IR
 	movwf	BAUDCON2
-	movlw	b'00100000'					; BRGH=0, SYNC=0
+	movlw	b'00100000'					;     - BRGH=0, SYNC=0
 	movwf	TXSTA2
-	movlw	.102						; SPBRGH:SPBRG = .102 : 2403 BAUD @ 16 MHz
+	movlw	.102						;     - SPBRGH:SPBRG = .102 : 2403 BAUD @ 16 MHz
 	movwf	SPBRG2
+	clrf	SPBRGH2
 	movlw	b'10010000'
 	movwf	RCSTA2
-	banksel	common
-	bsf		ir_power					; power-up IR
+	banksel	common						;     - back to bank common
+	bsf		ir_power					;     - power-up IR
 	btfss	ir_power
 	bra		$-6
 	return
@@ -126,32 +144,30 @@
 	bsf		mcp_power					; power-up instrumentation amp
 	btfss	mcp_power
 	bra		$-6
-	banksel	TXSTA2
+	banksel	TXSTA2						; select bank for IO register access
 	clrf	TXSTA2
 	clrf	RCSTA2
-	banksel	common
+	banksel	common						; back to bank common
 
 	; It may be digital, check for voltage when isolator is powered
 	bcf		s8_npower					; power S8 HUD
-	WAITMS	d'1'						; very short delay
-
-	btfsc	PORTG,2						; RX2=1?
-	bra	enable_s8_2						; YES - digital
-	WAITMS	d'30'
+	WAITMS	d'1'						; wait 1 ms
 	btfsc	PORTG,2						; RX2=1?
 	bra		enable_s8_2					; YES - digital
-
-	; Not found, set to analog (fail-safe)
+	WAITMS	d'30'						; NO  - wait 30 ms
+	btfsc	PORTG,2						;     - RX2=1?
+	bra		enable_s8_2					;       YES - digital
+	;bra	enable_s8_analog			;       NO  - not found, set to analog (fail-safe)
 
 enable_s8_analog:
-	; S8 Analog
+	; S8 analog interface
 	bsf		s8_npower					; power-down S8 HUD
-	bcf		s8_digital					; clear flag
+	bcf		s8_digital_avail			; digital S8 interface not available
 	return
 
-enable_s8_2:							; S8 Digital
-	banksel BAUDCON2
-	movlw	b'00000000'					; BRG16=0			; normal for S8
+enable_s8_2:							; configure S8 digital interface
+	banksel BAUDCON2					; select bank for IO register access
+	movlw	b'00000000'					; BRG16=0, normal for S8
 	movwf	BAUDCON2
 	movlw	b'00100000'					; BRGH=0, SYNC=0
 	movwf	TXSTA2
@@ -159,21 +175,22 @@
 	movwf	SPBRG2
 	movlw	b'10010000'
 	movwf	RCSTA2
-	banksel	common
-	bsf		s8_digital					; set flag
+	banksel	common						; back to bank common
+	bsf		s8_digital_avail			; digital S8 interface available
 	return
 
+ ENDIF	; _external_sensor
+
 ;=============================================================================
 
 	global	enable_rs232
 enable_rs232:
-	call	speed_normal				; 16 MHz
-enable_rs232_2:
-	movlw	T2CON_NORMAL
-	cpfseq	T2CON
-	bra		enable_rs232_2				; wait until speed is normal
-	bcf		PORTE,0						; start comms
-;init serial port1 (TRISC6/7)
+	call	request_speed_normal		; request CPU speed change to normal speed
+enable_rs232_1:
+	btfss	speed_is_normal				; speed = normal?
+	bra		enable_rs232_1				; NO - wait for ISR to adjust speed
+	bcf		PORTE,0						; start comm
+	;initialize serial port1 (TRISC6/7)
 	movlw	b'00100100'					; BRGH=1, SYNC=0
 	movwf	TXSTA1
 	movlw	b'10010000'
@@ -186,13 +203,13 @@
 	clrf	RCSTA1
 	clrf	TXSTA1						; UART disable
 	bcf		PORTC,6						; TX hard to GND
-	bsf		PORTE,0						; stop comms
+	bsf		PORTE,0						; stop comm
 	return
 
 
 	global	rs232_wait_tx
 rs232_wait_tx:
-	btfss	TXSTA1,TRMT					; RS232 Busy?
+	btfss	TXSTA1,TRMT					; RS232 busy?
 	bra		rs232_wait_tx				; YES - wait...
 
 	btfss	ble_available				; ble available?
@@ -205,45 +222,44 @@
 
 	global	rs232_wait_tx2
 rs232_wait_tx2:
-	banksel	TXSTA2
-rs232_wait_tx2_1:
+	banksel	TXSTA2						; select bank for IO register access
+rs232_wait_tx2_loop:
 	btfss	TXSTA2,TRMT					; RS232 busy?
-	bra		rs232_wait_tx2_1			; YES - wait...
-	banksel	common
+	bra		rs232_wait_tx2_loop			; YES - wait...
+	banksel	common						; back to bank common
 	return								; done
 
+
 	global	rs232_get_byte
 rs232_get_byte:
-	bcf		rs232_receive_overflow		; clear flag
-	clrf	uart1_temp					; set uart1_temp to .10 without using WREG: first clear to 0, then...
-	bsf		uart1_temp,1				; set bit 1 (value 2),
-	bsf		uart1_temp,3				; and bit 3 (value 8).
-	clrf	uart2_temp
-	clrf	uart3_temp
-rs232_get_byte2:
-	btfsc	PIR1,RCIF					; data arrived?
-	return								; YES
-	decfsz	uart3_temp,F
-	bra		rs232_get_byte2
-	decfsz	uart2_temp,F
-	bra		rs232_get_byte2
-	decfsz	uart1_temp,F
-	bra		rs232_get_byte2
-										; timeout occurred (about 400ms)
-	bsf		rs232_receive_overflow		; set flag
-rs232_get_byte3:
-	bcf		RCSTA1,CREN					; clear receiver status
-	bsf		RCSTA1,CREN
-	return								; and return anyway
+	bcf		rs232_rx_timeout			; clear timeout flag
+										; set timeout timer to approx. 400 ms:
+	clrf	uart_timeout_timer+0		; set low   byte of timeout timer to 0
+	clrf	uart_timeout_timer+1		; set high  byte of timeout timer to 0
+										; set upper byte of timeout timer to 10 without using WREG:
+	clrf	uart_timeout_timer+2		; first clear to 0, then...
+	bsf		uart_timeout_timer+2,1		; set bit 1 (value 2),
+	bsf		uart_timeout_timer+2,3		; and bit 3 (value 8).
+
+rs232_get_byte_loop:
+	btfsc	PIR1,RCIF					; received a data byte?
+	return								; YES - done
+	decfsz	uart_timeout_timer+0,F		; NO  - decrement low byte of timer, became zero?
+	bra		rs232_get_byte_loop			;       NO  - loop
+	decfsz	uart_timeout_timer+1,F		;       YES - decrement high byte of timer, became zero?
+	bra		rs232_get_byte_loop			;             NO  - loop
+	decfsz	uart_timeout_timer+2,F		;             YES - decrement upper byte of timer, became zero?
+	bra		rs232_get_byte_loop			;                   NO  - loop
+	bsf		rs232_rx_timeout			;                   YES - set timeout flag
+	bcf		RCSTA1,CREN					;                       - clear receiver status
+	bsf		RCSTA1,CREN					;                       - ...
+	return								;                       - and return anyway
 
 ;=============================================================================
 
 	global	do_logoffset_common_write
 do_logoffset_common_write:
-	movlw	0x26
-	cpfslt	hi								; is offset < 0x26?? (decimal 9983 at max, hence save for another +10) ?
-	return									; NO  - abort
-	movff	lo,EEDATA						; YES - proceed writing offset to EEPROM
+	movff	lo,EEDATA
 	write_int_eeprom 0x0D
 	movff	hi,EEDATA
 	write_int_eeprom 0x0E
@@ -255,13 +271,15 @@
 	read_int_eeprom 0x0D
 	movff	EEDATA,lo
 	read_int_eeprom 0x0E
-	movff	EEDATA,hi						; existing logbook offset into lo:hi
+	movff	EEDATA,hi
 	return
 
+;=============================================================================
 
 	global	update_battery_registers
 update_battery_registers:
-	; save battery_gauge:6 into EEPROM 0x07-0x0C
+	; save battery gauge to EEPROM 0x07-0x0C
+	bsf		block_battery_gauge			; suspend ISR from accessing the battery gauge
 	clrf	EEADRH
 	movff	battery_gauge+0,EEDATA
 	write_int_eeprom 0x07
@@ -275,11 +293,36 @@
 	write_int_eeprom 0x0B
 	movff	battery_gauge+5,EEDATA
 	write_int_eeprom 0x0C
-	movff	battery_type,EEDATA				; =0:1.5V, =1:3,6V Saft, =2:LiIon 3,7V/0.8Ah, =3:LiIon 3,7V/3.1Ah, =4: LiIon 3,7V/2.3Ah
+	movff	battery_type,EEDATA			; =0:1.5V, =1:3.6V Saft, =2:LiIon 3.7V/0.8Ah, =3:LiIon 3.7V/3.1Ah, =4: LiIon 3.7V/2.3Ah
 	write_int_eeprom 0x0F
+	bcf		block_battery_gauge			; allow ISR to access the battery gauge again
 	return
 
 
+	global	retrieve_battery_registers
+retrieve_battery_registers:
+	; retrieve battery gauge from EEPROM 0x07-0x0C
+	bsf		block_battery_gauge			; suspend ISR from accessing the battery gauge
+	clrf	EEADRH
+	read_int_eeprom 0x07
+	movff	EEDATA,battery_gauge+0
+	read_int_eeprom 0x08
+	movff	EEDATA,battery_gauge+1
+	read_int_eeprom 0x09
+	movff	EEDATA,battery_gauge+2
+	read_int_eeprom 0x0A
+	movff	EEDATA,battery_gauge+3
+	read_int_eeprom 0x0B
+	movff	EEDATA,battery_gauge+4
+	read_int_eeprom 0x0C
+	movff	EEDATA,battery_gauge+5
+	read_int_eeprom 0x0F
+	movff	EEDATA,battery_type			; =0:1.5V, =1:3,6V Saft, =2:LiIon 3,7V/0.8Ah, =3:LiIon 3,7V/3.1Ah, =4: LiIon 3,7V/2.3Ah
+	bcf		block_battery_gauge			; allow ISR to access the battery gauge again
+	return
+
+;=============================================================================
+
 	global	vault_decodata_into_eeprom
 vault_decodata_into_eeprom:
 	; Vault in EEPROM 512...1023
@@ -288,56 +331,66 @@
 	; Store 0x700 to 0x780 (pres_tissue_N2 and pres_tissue_He)
 	movlw	HIGH .512						; =2
 	movwf	EEADRH
+
+	; indicate valid data in vault
 	movlw	0xAA
 	movwf	EEDATA
 	write_int_eeprom .0
-	; Store date/time
-	movff	year,EEDATA
+
+	; store date/time
+	SMOVSS	rtc_year,rtc_latched_year		; ISR-safe 6 byte copy of date and time
+	movff	rtc_latched_year+0,EEDATA
 	write_int_eeprom .1
-	movff	month,EEDATA
+	movff	rtc_latched_year+1,EEDATA
 	write_int_eeprom .2
-	movff	day,EEDATA
+	movff	rtc_latched_year+2,EEDATA
 	write_int_eeprom .3
-	movff	hours,EEDATA
+	movff	rtc_latched_year+3,EEDATA
 	write_int_eeprom .4
-	movff	mins,EEDATA
+	movff	rtc_latched_year+4,EEDATA
 	write_int_eeprom .5
-	movff	secs,EEDATA
+	movff	rtc_latched_year+5,EEDATA
 	write_int_eeprom .6
 
-	movff	int_O_CNS_fraction+0,EEDATA
-	write_int_eeprom .7
-	movff	int_O_CNS_fraction+1,EEDATA
-	write_int_eeprom .8
-	movff	int_O_desaturation_time+0,EEDATA
-	write_int_eeprom .9
-	movff	int_O_desaturation_time+1,EEDATA
-	write_int_eeprom .10
-	movff	surface_interval+0,EEDATA
-	write_int_eeprom .11
-	movff	surface_interval+1,EEDATA
-	write_int_eeprom .12
-	movff	int_O_gradient_factor+0,EEDATA	; value limited to 255, only lower byte in use for value
+	movff	int_O_CNS_current+0,EEDATA		; get current CNS, low  byte
+	write_int_eeprom .7						; store value
+	movff	int_O_CNS_current+1,EEDATA		; get current CNS, high byte
+	write_int_eeprom .8						; store value
+
+	movff	int_O_desaturation_time+0,EEDATA; get desaturation time, low  byte
+	write_int_eeprom .9						; store value
+	movff	int_O_desaturation_time+1,EEDATA; get desaturation time, high byte
+	write_int_eeprom .10					; store value
+
+	SMOVII	surface_interval,mpr			; ISR-safe copy of surface interval
+	movff	mpr+0,EEDATA					; get surface interval, low  byte
+	write_int_eeprom .11					; store value
+	movff	mpr+1,EEDATA					; get surface interval, high byte
+	write_int_eeprom .12					; store value
+
+	movff	int_O_lead_supersat+0,EEDATA	; get leading tissue's supersaturation, value is limited to 255 so only the lower byte is used for the value
 	write_int_eeprom .13
-	movff	int_O_nofly_time+0,EEDATA
-	write_int_eeprom .14
-	movff	int_O_nofly_time+1,EEDATA
-	write_int_eeprom .15
 
-	; Tissue data from 16 to 144
+	movff	int_O_nofly_time+0,EEDATA		; get time, low  byte
+	write_int_eeprom .14					; store value
+	movff	int_O_nofly_time+1,EEDATA		; get time, high byte
+	write_int_eeprom .15					; store value
+
+	; tissue data from 16 to 144
 	movlw	.16
 	movwf	EEADR
-	movlw	.128
+	movlw	.128							; 2 * 16 floats = 2*16*4 byte = 128 byte
 	movwf	lo
-	lfsr	FSR1,0x700						; pres_tissue_N2+0, 32*4Byte Float = 128Bytes
+	lfsr	FSR1,0x700						; pres_tissue_N2+0
 vault_decodata_into_eeprom2:
 	movff	POSTINC1,EEDATA
 	call	write_eeprom					; EEDATA into EEPROM@EEADR
 	incf	EEADR,F
 	decfsz	lo,F							; all done?
-	bra		vault_decodata_into_eeprom2		; NO
-	clrf	EEADRH
-	return
+	bra		vault_decodata_into_eeprom2		; NO  - loop
+	clrf	EEADRH							; YES - reset EEPROM pointer
+	return									;     - done
+
 
 	global	restore_decodata_from_eeprom
 restore_decodata_from_eeprom:
@@ -346,57 +399,67 @@
 	movlw	HIGH .512						; =2
 	movwf	EEADRH
 
-	; Restore date/time
+	; restore date and time
 	read_int_eeprom .1
-	movff	EEDATA,year
+	movff	EEDATA,rtc_latched_year
 	read_int_eeprom .2
-	movff	EEDATA,month
+	movff	EEDATA,rtc_latched_month
 	read_int_eeprom .3
-	movff	EEDATA,day
+	movff	EEDATA,rtc_latched_day
 	read_int_eeprom .4
-	movff	EEDATA,hours
+	movff	EEDATA,rtc_latched_hour
 	read_int_eeprom .5
-	movff	EEDATA,mins
+	movff	EEDATA,rtc_latched_mins
 	read_int_eeprom .6
-	movff	EEDATA,secs
-	call	rtc_set_rtc
+	movff	EEDATA,rtc_latched_secs
+	call	rtc_set_rtc						; write time and date to RTC module
+
+	read_int_eeprom .7						; read CNS%, low  byte
+	movff	EEDATA,int_O_CNS_current+0		; restore value
+	read_int_eeprom .8						; read CNS%, high byte
+	movff	EEDATA,int_O_CNS_current+1		; restore value
 
-	read_int_eeprom .7
-	movff	EEDATA,int_O_CNS_fraction+0
-	read_int_eeprom .8
-	movff	EEDATA,int_O_CNS_fraction+1
-	read_int_eeprom .9
-	movff	EEDATA,int_O_desaturation_time+0
-	read_int_eeprom .10
-	movff	EEDATA,int_O_desaturation_time+1
-	read_int_eeprom .11
-	movff	EEDATA,surface_interval+0
-	read_int_eeprom .12
-	movff	EEDATA,surface_interval+1
-	read_int_eeprom .13
-	movff	EEDATA,int_O_gradient_factor+0
-	read_int_eeprom .14
-	movff	EEDATA,int_O_nofly_time+0
-	read_int_eeprom .15
-	movff	EEDATA,int_O_nofly_time+1
+	read_int_eeprom .9						; read desaturation time, low  byte
+	movff	EEDATA,int_O_desaturation_time+0; restore value
+	read_int_eeprom .10						; read desaturation time, high byte
+	movff	EEDATA,int_O_desaturation_time+1; restore value
 
-	; Tissue data from 16 to 144
+	read_int_eeprom .11						; read surface interval, low  byte
+	movff	EEDATA,mpr+0					; cache value in mpr
+	read_int_eeprom .12						; read surface interval, high byte
+	movff	EEDATA,mpr+1					; cache value in mpr
+	SMOVII	mpr,surface_interval			; ISR-safe copy-back of surface interval
+
+	read_int_eeprom .13						; read leading tissue's supersaturation
+	movff	EEDATA,int_O_lead_supersat+0	; restore value
+
+	read_int_eeprom .14						; read no-fly/no-altitude time, low  byte
+	movff	EEDATA,int_O_nofly_time+0		; restore value
+	read_int_eeprom .15						; read no-fly/no-altitude time, high byte
+	movff	EEDATA,int_O_nofly_time+1		; restore value
+
+	; tissue data from 16 to 144
 	movlw	.16
 	movwf	EEADR
-	movlw	.128
+	movlw	.128							; 2 * 16 floats = 2*16*4 byte = 128 byte
 	movwf	lo
-	lfsr	FSR1,0x700						; pres_tissue_N2+0, 32*4Byte Float = 128 Bytes
+	lfsr	FSR1,0x700						; pres_tissue_N2+0
 restore_decodata_from_eeprom2:
 	call	read_eeprom						; EEPROM@EEADR into EEDATA
 	movff	EEDATA,POSTINC1
 	incf	EEADR,F
 	decfsz	lo,F							; all done?
-	bra		restore_decodata_from_eeprom2	; NO
-	clrf	EEADRH
+	bra		restore_decodata_from_eeprom2	; NO  - loop
+	clrf	EEADRH							; YES
 	return
 
+;=============================================================================
 
+	global	reset_battery_pointer			; called from comm and menu tree
 	global	reset_battery_internal_only
+reset_battery_pointer:						; reset battery pointer 0x07-0x0C and battery gauge
+	btfsc	battery_gauge_available			; something to reset?
+	call	lt2942_charge_done				; YES - reset accumulating registers to 0xFFFF
 reset_battery_internal_only:
 	clrf	EEADRH
 	clrf	EEDATA							; delete to zero
@@ -406,18 +469,23 @@
 	write_int_eeprom 0x0A
 	write_int_eeprom 0x0B
 	write_int_eeprom 0x0C
-	banksel	battery_gauge+0
-	clrf	battery_gauge+0
+
+	bsf		block_battery_gauge				; suspend ISR from accessing the battery gauge
+	banksel	battery_gauge					; select bank ISR data
+	clrf	battery_gauge+0					; null the battery gauge
 	clrf	battery_gauge+1
 	clrf	battery_gauge+2
 	clrf	battery_gauge+3
 	clrf	battery_gauge+4
 	clrf	battery_gauge+5
-	banksel	common
+	banksel	common							; back to bank common
+	bcf		block_battery_gauge				; allow ISR to access the battery gauge again
+
 	movlw	.100
-	movwf	batt_percent
+	movwf	batt_percent					; set battery level to 100%
 	return
 
+;=============================================================================
 
 	global	eeprom_reset_logbook_pointers
 eeprom_reset_logbook_pointers:
@@ -432,4 +500,6 @@
 	write_int_eeprom .17					; ...and the backup counter, too
 	return
 
+;=============================================================================
+
 	END