--- a/src/eeprom_rs232.asm	Thu Mar 05 15:06:14 2020 +0100
+++ b/src/eeprom_rs232.asm	Tue Apr 28 17:34:31 2020 +0200
@@ -1,6 +1,6 @@
 ;=============================================================================
 ;
-;   File eeprom_rs232.asm                     combined next generation V3.08.8
+;   File eeprom_rs232.asm                   * combined next generation V3.09.4n
 ;
 ;   Internal EEPROM, RS232
 ;
@@ -21,20 +21,20 @@
 
 	extern	lt2942_charge_done
 
+
+;=============================================================================
+eeprom	CODE
+;=============================================================================
+
 ;-----------------------------------------------------------------------------
 ;
-;			for EEPROM Macros and Memory Map, see eeprom_rs232.inc
+; EEPROM Functions - for EEPROM Macros and Memory Map, see eeprom_rs232.inc
 ;
 ;-----------------------------------------------------------------------------
 
-ee_rs232	CODE
-
-;=============================================================================
-;   EEPROM Functions
-;=============================================================================
 
 ;-----------------------------------------------------------------------------
-; read from internal EEPROM
+; Read from internal EEPROM
 ;
 ; Input:   EEADRH:EEADR = EEPROM address
 ; Output:  EEDATA
@@ -42,13 +42,14 @@
 ;
 	global	read_eeprom
 read_eeprom:
-	bcf		EECON1,EEPGD					;
-	bcf		EECON1,CFGS						;
-	bsf		EECON1,RD						;
-	return
+	bcf		EECON1,EEPGD					; access data EEPROM
+	bcf		EECON1,CFGS						; ...
+	bsf		EECON1,RD						; initiate reading
+	return									; done
+
 
 ;-----------------------------------------------------------------------------
-; write into internal EEPROM
+; Write into internal EEPROM
 ;
 ; Input:   EEADRH:EEADR = EEPROM address
 ;          EEDATA = byte to write
@@ -56,10 +57,10 @@
 ;
 	global	write_eeprom
 write_eeprom:
-	bcf		EECON1,EEPGD					;
-	bcf		EECON1,CFGS						;
-	bsf		EECON1,WREN						;
-	bcf		INTCON,GIE						; disable interrupts for the next 5 instructions
+	bcf		EECON1,EEPGD					; access data EEPROM
+	bcf		EECON1,CFGS						; ...
+	bsf		EECON1,WREN						; enable writing
+	bcf		INTCON,GIE						; disable interrupts
 	movlw	0x55							; unlock sequence
 	movwf	EECON2							; ...
 	movlw	0xAA							; ...
@@ -67,13 +68,14 @@
 	bsf		EECON1,WR						; start write operation
 write_eeprom_loop:
 	btfsc	EECON1,WR						; write completed?
-	bra		write_eeprom_loop				; NO - loop waiting
-	bcf		EECON1,WREN						;
-	bsf		INTCON,GIE						; ...but the flag for the ISR routines were still set, so they will interrupt now!
-	return
+	bra		write_eeprom_loop				; NO  - loop waiting
+	bcf		EECON1,WREN						; YES - disable writing
+	bsf		INTCON,GIE						;     - re-enable interrupts 
+	return									;     - done
+
 
 ;-----------------------------------------------------------------------------
-; these 2 functions are meant to be used through the macros, see eeprom_rs232!
+; EEPROM read and write Functions to be used via Macros
 ;
 	global	eeprom_read_common
 eeprom_read_common:
@@ -97,44 +99,46 @@
 	bra		eeprom_write_common_loop		; NO  - loop
 	return									; YES - done
 
+
 ;-----------------------------------------------------------------------------
-; REad OSTC serial number
+; Read OSTC Serial Number
 ;
 	global	eeprom_serial_number_read
 eeprom_serial_number_read:
-	EEPROM_II_READ eeprom_ostc_serial,mpr
-	return
+	EEPROM_II_READ eeprom_ostc_serial,mpr	; read serial number
+	return									; done
+
 
 ;-----------------------------------------------------------------------------
-; Read and write dive number offset
+; Read and Write Dive Number Offset
 ;
 	global	eeprom_log_offset_read
 eeprom_log_offset_read:
-	EEPROM_II_READ	eeprom_log_offset,mpr
-	return
+	EEPROM_II_READ	eeprom_log_offset,mpr	; read log offset
+	return									; done
 
 	global	eeprom_log_offset_write
 eeprom_log_offset_write:
-	EEPROM_II_WRITE mpr,eeprom_log_offset
-	return
+	EEPROM_II_WRITE mpr,eeprom_log_offset	; write log-offset
+	return									; done
 
 
 ;-----------------------------------------------------------------------------
-; Read and write total number of dives
+; Read and Write total Number of Dives
 ;
 	global	eeprom_total_dives_read
 eeprom_total_dives_read:
-	EEPROM_II_READ	eeprom_num_dives,mpr
-	return
+	EEPROM_II_READ	eeprom_num_dives,mpr	; read total dives
+	return									; done
 
 	global	eeprom_total_dives_write
 eeprom_total_dives_write:
-	EEPROM_II_WRITE mpr,eeprom_num_dives
-	return
+	EEPROM_II_WRITE mpr,eeprom_num_dives	; write total dives
+	return									; done
 
 
 ;-----------------------------------------------------------------------------
-; Read and write the battery gauge and type
+; Read and Write the Battery Type and Gauge Reading
 ;
 	global	eeprom_battery_gauge_read
 eeprom_battery_gauge_read:
@@ -143,7 +147,7 @@
 	EEPROM_CC_READ eeprom_battery_type, battery_type		; 1 byte read from EEPROM
 	EEPROM_RR_READ eeprom_battery_gauge,battery_gauge,.6	; 6 byte read from EEPROM
 	bcf		block_battery_gauge								; allow ISR to access the battery gauge again
-	return
+	return													; done
 
 	global	eeprom_battery_gauge_write
 eeprom_battery_gauge_write:
@@ -152,16 +156,28 @@
 update_battery_gauge:
 	EEPROM_RR_WRITE battery_gauge,eeprom_battery_gauge,.6	; 6 byte write to EEPROM
 	bcf		block_battery_gauge								; allow ISR to access the battery gauge again
-	return
+	return													; done
 
 
 ;-----------------------------------------------------------------------------
-; Read and write the deco status
+; Memorize the Checksum of the Firmware in the update Storage
+;
+	global	eeprom_memorize_fw_checksum
+eeprom_memorize_fw_checksum:
+	EXT_FLASH_ADDR 0x3E000D									; address firmware ID at 0x3E000D
+	FLASH_CW_READ_0x40										; read    firmware ID to WREG
+	movff	WREG,buffer+.5									; append  firmware ID to checksum
+	EEPROM_RR_WRITE buffer,eeprom_fw_chksum_current,.6		; do a  6 byte write  to EEPROM
+	return													; done
+
+
+;-----------------------------------------------------------------------------
+; Read and Write the Deco Status
 ;
 	global	eeprom_deco_data_read
 eeprom_deco_data_read:
 
-	btfsc	RCON,POR												; was there a power outage ?
+	btfsc	RCON,POR												; was there a power outage?
 	bra		eeprom_deco_data_read_1									; NO  - RTC is up-to-date
 
 	EEPROM_RR_READ eeprom_deco_data_timestamp,rtc_latched_year,.6	;   6 byte read from EEPROM
@@ -220,98 +236,115 @@
 	return															;   done
 
 
-
 ;=============================================================================
-;   RS232 Functions
+rs232	CODE
 ;=============================================================================
 
-	global	disable_ir_s8
-disable_ir_s8:
-	banksel	TXSTA2						; select bank for IO register access
-	clrf	TXSTA2
-	clrf	RCSTA2
-	banksel	common						; back to bank common
-	bcf		PIE3,RC2IE					; disable RC2 INT
-	bcf		ir_power					; IR off
-	bcf		mcp_power					; power-down instrumentation amp
-	bsf		s8_npower					; power-down S8 digital interface
-	bcf		s8_digital_avail			; digital S8 interface not available
-	return
+;-----------------------------------------------------------------------------
+;
+; RS232 Functions
+;
+;-----------------------------------------------------------------------------
 
 
-	global	enable_ir_s8
-enable_ir_s8:
+;-----------------------------------------------------------------------------
+; Switch-On the IR/S8 Port
+;
+	global	enable_ir_s8_analog
+enable_ir_s8_analog:
 	;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
-	movwf	TXSTA2
-	movlw	.102						;     - SPBRGH:SPBRG = .102 : 2403 BAUD @ 16 MHz
-	movwf	SPBRG2
-	clrf	SPBRGH2
-	movlw	b'10010000'
-	movwf	RCSTA2
-	banksel	common						;     - back to bank common
-	bsf		ir_power					;     - power-up IR
-	btfss	ir_power					;     - power-up confirmed?
-	bra		$-6							;       NO - loop and wait
-	bsf		PIE3,RC2IE					;     - enable RC2 INT
-	return								;     - done
+	btfsc	ext_input_s8_ana			; do we have an S8/analog input?
+	bra		enable_s8_analog			; YES - enable S8/analog  input
+	;bra	enable_ir					; NO  - enable IR digital input
 
-enable_s8:
+enable_ir:
+	banksel	BAUDCON2					; select bank for IO register access
+	movlw	b'00100000'					; speed generator configuration: BRG16=0, inverted for IR
+	movwf	BAUDCON2					; ...
+	movlw	b'00100000'					; TX configuration: BRGH=0, SYNC=0
+	movwf	TXSTA2						; ...
+	movlw	.102						; speed configuration: SPBRGH:SPBRG = .102 : 2403 BAUD @ 16 MHz
+	movwf	SPBRG2						; ...
+	clrf	SPBRGH2						; ...
+	movlw	b'10010000'					; RX configuration
+	movwf	RCSTA2						; ...
+	banksel	common						; back to bank common
+	bsf		ir_power					; power-up IR
+	btfss	ir_power					; power-up confirmed?
+	bra		$-6							; NO - loop and wait
+	bsf		PIE3,RC2IE					; enable RC2 INT
+	return								; done
+
+enable_s8_analog:
 	banksel	TXSTA2						; select bank for IO register access
 	clrf	TXSTA2						; reset UART 2 TX function
 	clrf	RCSTA2						; reset UART 2 RX function
 	banksel	common						; back to bank common
 
-	bsf		mcp_power					; power-up instrumentation amp (for analog AND digital)
+	bsf		mcp_power					; power-up instrumentation amp (used by S8 and analog input)
 	btfss	mcp_power					; power-up completed?
 	bra		$-4							; NO - loop
 
-	; toggle for digital/analog
+	; branch according to S8 / analog selection
 	TSTOSS	opt_s8_mode					; =0: analog, =1: digital RS232
-	bra		enable_s8_analog			; -> analog
+	bra		enable_analog				; -> analog
 
 	; configure S8 digital interface
 	bcf		s8_npower					; power S8 HUD (inverted via P-MOS transistor)
 	WAITMS	d'30'						; NO  - wait 30 ms
 	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
-	movlw	.25							; SPBRGH:SPBRG = .25 : 9615 BAUD @ 16 MHz
-	movwf	SPBRG2
-	movlw	b'10010000'
-	movwf	RCSTA2
+	movlw	b'00000000'					; speed generator configuration: BRG16=0, normal for S8
+	movwf	BAUDCON2					; ...
+	movlw	b'00100000'					; TX configuration: BRGH=0, SYNC=0
+	movwf	TXSTA2						; ...
+	movlw	.25							; speed configuration: SPBRGH:SPBRG = .25 : 9615 BAUD @ 16 MHz
+	movwf	SPBRG2						; ...
+	movlw	b'10010000'					; RX configuration
+	movwf	RCSTA2						; ...
 	banksel	common						; back to bank common
 	bsf		PIE3,RC2IE					; enable RC2 INT
-	bsf		s8_digital_avail			; digital S8 interface available
 	return
 
-enable_s8_analog:
+enable_analog:
 	; S8 analog interface
 	bcf		PIE3,RC2IE					; disable RC2 INT
-	bsf		s8_npower					; power-down S8 HUD
-	bcf		s8_digital_avail			; digital S8 interface not available
-	return
+	bsf		s8_npower					; power-down S8 digital interface
+	return								; done
 
 
-	global	ir_s8_wait_tx
-ir_s8_wait_tx:
+;-----------------------------------------------------------------------------
+; Shut-Down the IR/S8 Port
+;
+	global	disable_ir_s8_analog
+disable_ir_s8_analog:
 	banksel	TXSTA2						; select bank for IO register access
-rs232_wait_tx2_loop:
-	btfss	TXSTA2,TRMT					; RS232 busy?
-	bra		rs232_wait_tx2_loop			; YES - wait...
-	banksel	common						; NO  - back to bank common
+	clrf	TXSTA2						; shut down TX function
+	clrf	RCSTA2						; shut down RX function
+	banksel	common						; back to bank common
+	bcf		PIE3,RC2IE					; disable RC2 INT
+	bcf		ir_power					; power down IR receiver
+	bcf		mcp_power					; power-down instrumentation amp
+	bsf		s8_npower					; power-down S8 digital interface
+	return								; done
+
+
+;-----------------------------------------------------------------------------
+; Send Byte in WREG via the IR/S8 Port
+;
+	global	ir_s8_tx_single
+ir_s8_tx_single:
+	banksel	TXSTA2						; UART 2 is outside of the access RAM
+	movwf	TXREG2						; transmit byte
+ir_s8_tx_single_loop:
+	btfss	TXSTA2,TRMT					; TX completed?
+	bra		ir_s8_tx_single_loop		; NO  - wait...
+	banksel	common						; YES - back to bank common
 	return								;     - done
 
+
 ;-----------------------------------------------------------------------------
-
+; Switch-On USB/BT Port
+;
 	global	enable_rs232
 enable_rs232:
 	call	request_speed_normal		; request CPU speed change to normal speed
@@ -324,21 +357,44 @@
 	movwf	TXSTA1						;     - ...
 	movlw	b'10010000'					;     - RX configuration: port enabled, RX enabled
 	movwf	RCSTA1						;     - ...
-	movlw	HIGH(.65536-rx_timeout*.32)	;     - define TMR5H initialization value for RX timeout
-	movwf	rx_timoeut_tmr5h_load		;     - store for later use
+ IFNDEF _comm_debug
+	movlw	HIGH(.65536-rx_timeout*.32)	;     - define TMR5H initialization value for RX timeout (rx_timeout defined in hwos.inc)
+ ELSE
+	include	"math.inc"
+	movff	opt_comm_timeout,xA+0		;     - get timeout setting in multiples of 10 ms (opt_comm_timeout: 10 .. 200 x 10 ms)
+	clrf	xA+1						;     - ...
+	MOVLI	.320,xB						;     - multiply with 10 to get timeout in ms and 32 because tmr5 ticks 32x per ms
+	call	mult16x16					;     - xC = xA * xB = timer ticks to go until timeout
+	MOVII	xC,sub_b					;     - multiplication result is max. 64000
+	MOVLI	.65535,sub_a				;     - timer wraps around after 65535
+	call	subU16						;     - sub_c = sub_a - sub_b = start value for timer
+
+	movlw	.244						; safety maximum value for rx_timeout_tmr5h_load (minimum timeout interval)
+	cpfslt	sub_c+1						; result > safety value?
+	movwf	sub_c+1						; YES - revert to safety value
+
+	movf	sub_c+1,W					;     - keep only the upper byte as TMR5H initialization value for RX timeout
+ ENDIF
+	movwf	rx_timeout_tmr5h_load		;     - store for later use
 	return								;     - done
 
 
+;-----------------------------------------------------------------------------
+; Shut-Down USB/BT Port
+;
 	global	disable_rs232
 disable_rs232:
 	clrf	RCSTA1						; disable RX
 	clrf	TXSTA1						; disable TX
 	bcf		PORTC,6						; switch TX pin hard to GND
-	bsf		PORTE,0						; stop comm
+	bsf		PORTE,0						; power down BT chip
 	bcf		PORTJ,2						; /Reset (required for very old OSTC sport)
 	return
 
 
+;-----------------------------------------------------------------------------
+; Wait for last Byte to be sent out of USB/BT Port
+;
 	global	rs232_wait_tx				; ++++ do not touch WREG here! ++++
 rs232_wait_tx:
 	btfss	TXSTA1,TRMT					; last byte completely shifted out on TX pin?
@@ -350,36 +406,47 @@
 	return								;             YES - done
 
 
-										; ++++ make this code as fast as possible! ++++
-	global	rs232_get_byte				; ++++       do not touch WREG here!       ++++
-rs232_get_byte:
+;-----------------------------------------------------------------------------
+; Receive one Byte via the USB/BT Port
+;
+; ++++ make this code as fast as possible! ++++
+; ++++       do not touch WREG here!       ++++
+;
+	global	serial_rx_single
+serial_rx_single:
 	bcf		rs232_rx_timeout			; clear timeout flag
-	btfsc	PIR1,RCIF					; received a data byte? (bit is set on RX complete and reset on reading RCREG1)
-	return								; YES - done, received a byte (fast path)
-	movff	rx_timoeut_tmr5h_load,TMR5H	;     - load TMR5 high with timeout value
+	btfsc	PIR1,RCIF					; received a data byte? (bit is set on RX completion and reset on reading RCREG1)
+	return								; YES - done (fast path)
+	movff	rx_timeout_tmr5h_load,TMR5H	; NO  - load TMR5 high with timeout value
 	clrf	TMR5L						;     - load TMR5 low  with a zero, writing low starts the timer
 	bcf		PIR5,TMR5IF					;     - clear timer overflow flag
-rs232_get_byte_loop:
+serial_rx_single_loop:
 	btfsc	PIR1,RCIF					; received a data byte?
-	return								; YES - done, received a byte
+	return								; YES - done
 	btfss	PIR5,TMR5IF					; NO  - timer overflow (timeout)?
-	bra		rs232_get_byte_loop			;       NO  - continue looping
-	;bra	rs232_rx_get_timeout		;       YES - give up
-
-rs232_rx_get_timeout:
-	bsf		rs232_rx_timeout			; set timeout flag
-	bcf		RCSTA1,CREN					; clear receiver status by toggling CREN
-	bsf		RCSTA1,CREN					; ...
-	return								; done, given up
+	bra		serial_rx_single_loop		;       NO  - continue waiting
+	;bra	serial_rx_timeout			;       YES - timeout
 
 
 ;-----------------------------------------------------------------------------
-; Send and Receive functions to be used through the macros
+; Helper Function: Timeout in serial_rx_single / serial_tx_steam
+;
+serial_rx_timeout:
+	bsf		rs232_rx_timeout			; set timeout flag
+	bcf		RCSTA1,CREN					; clear receiver status: disable RX,
+	bsf		RCSTA1,CREN					;               ... enable again RX
+	return								; done
+
 
-; send a range of 1-256 bytes from memory to the RS232 interface
+;-----------------------------------------------------------------------------
+; Send and Receive Functions to be used via Macros
+;-----------------------------------------------------------------------------
+
+;-----------------------------------------------------------------------------
+; Send a Range of 1-256 Bytes from Memory via the USB/BT Port
 ;
-	global	serial_tx_ram
-serial_tx_ram:
+	global	serial_tx_steam
+serial_tx_steam:
 	movwf	eeprom_loop					; initialize loop counter (eeprom variable used here)
 serial_tx_ram_loop:
 	rcall	rs232_wait_tx				; wait for completion of last transmit
@@ -389,37 +456,36 @@
 	return								; YES - done
 
 
-; receive a range of 1-256 byte from the RS232 interface and write them to memory
+;-----------------------------------------------------------------------------
+; Receive a Range of 1-256 Byte via the USB/BT Port and write them to Memory
+; ++++ make this code as fast as possible! ++++
 ;
-	global	serial_rx_stream_ram		; ++++ make this code as fast as possible! ++++
-serial_rx_stream_ram:
+	global	serial_rx_stream
+serial_rx_stream:
 	movwf	eeprom_loop					; initialize loop counter (eeprom variable used here)
-serial_rx_stream_ram_loop_1:
+serial_rx_stream_loop:
 	btfss	PIR1,RCIF					; received a data byte? (bit is set on RX complete and reset on reading RCREG1)
-	bra		serial_rx_stream_ram_tmr	; NO  - enter loop with timeout
-	movff	RCREG1,POSTINC2				; YES - copy received byte to memory
-	decfsz	eeprom_loop,F				;     - decrement loop counter, became zero?
-	bra		serial_rx_stream_ram_loop_1	;       NO  - loop
-	bcf		rs232_rx_timeout			;       YES - clear timeout flag
-	return								;           - all bytes received, done
-serial_rx_stream_ram_tmr:
-	movff	rx_timoeut_tmr5h_load,TMR5H	; load TMR5 high with timeout value
-	clrf	TMR5L						; load TMR5 low  with a zero, writing low starts the timer
+	bra		serial_rx_stream_tmr		; NO  - enter receive loop with timeout
+	;bra	serial_rx_stream_received	; YES - copy to memory, tick counter, ...
+
+serial_rx_stream_received:
+	movff	RCREG1,POSTINC2				; copy received byte to memory
+	decfsz	eeprom_loop,F				; decrement loop counter, became zero?
+	bra		serial_rx_stream_loop		; NO  - await next byte
+	bcf		rs232_rx_timeout			; YES - clear timeout flag
+	return								;     - all bytes received, done
+
+serial_rx_stream_tmr:
+	movff	rx_timeout_tmr5h_load,TMR5H	; load TMR5 high with timeout value
+	clrf	TMR5L						; load TMR5 low  with a zero, writing to low starts the timer
 	bcf		PIR5,TMR5IF					; clear timer overflow flag
-serial_rx_stream_ram_loop_2a:
-	clrf	TMR5L						; restart timer (see above)
-serial_rx_stream_ram_loop_2b:
-	btfss	PIR1,RCIF					; received a data byte? (bit is set on RX complete and reset on reading RCREG1)
-	bra		serial_rx_stream_ram_chk	; NO  - check timeout
-	movff	RCREG1,POSTINC2				; YES - copy received byte to memory
-	decfsz	eeprom_loop,F				;     - decrement loop counter, became zero?
-	bra		serial_rx_stream_ram_loop_2a;       NO  - loop
-	bcf		rs232_rx_timeout			;       YES - clear timeout flag
-	return								;           - all bytes received, done
-serial_rx_stream_ram_chk:
-	btfss	PIR5,TMR5IF					; timer overflow (timeout)?
-	bra		serial_rx_stream_ram_loop_2b; NO  - continue looping
-	bra		rs232_rx_get_timeout		; YES - give up
+serial_rx_stream_tmr_loop:
+	btfsc	PIR1,RCIF					; received a data byte? (bit is set on RX complete and reset on reading RCREG1)
+	bra		serial_rx_stream_received	; YES - copy to memory, tick counter, ...
+	btfss	PIR5,TMR5IF					; NO  - timer overflow (timeout)?
+	bra		serial_rx_stream_tmr_loop	;       NO  - continue waiting
+	bra		serial_rx_timeout			;       YES - timeout
 
 ;-----------------------------------------------------------------------------
+
 	END