--- a/src/external_flash.asm	Wed Apr 10 10:51:07 2019 +0200
+++ b/src/external_flash.asm	Mon Jun 03 14:01:48 2019 +0200
@@ -1,6 +1,6 @@
 ;=============================================================================
 ;
-;   File external_flash.asm											## V2.98c
+;   File external_flash.asm                    combined next generation V3.0.1
 ;
 ;   External flash
 ;
@@ -12,14 +12,20 @@
 	#include "hwos.inc"
 	#include "wait.inc"
 
-ext_flash		CODE
+ext_flash	CODE
 
 ;=============================================================================
 
+; increase flash address by one
+;
 	global	incf_ext_flash_address_p1
-incf_ext_flash_address_p1:					; Increase by one
-	movlw		.1
+incf_ext_flash_address_p1:
+	movlw	.1
+	;bra	incf_ext_flash_address0
 
+
+; increase flash address by value in WREG
+;
 	global	incf_ext_flash_address0
 incf_ext_flash_address0:
 	addwf	ext_flash_address+0,F			; increase address
@@ -29,32 +35,40 @@
 
 	movlw	0x40
 	cpfseq	ext_flash_address+2				; at address 40FFFF?
-	return									; No, return
+	return									; NO -  return
 ;	clrf	ext_flash_address+0
 ;	clrf	ext_flash_address+1
-	clrf	ext_flash_address+2				; Yes, rollover to 0x000000
+	clrf	ext_flash_address+2				; YES - rollover to 0x000000
 	return
 
 
+; increase flash address by one with roll-over at 0x200000 to 0x000000
+;
 	global	incf_ext_flash_address0_p1_0x20
-incf_ext_flash_address0_p1_0x20:			; Increase by one
+incf_ext_flash_address0_p1_0x20:			; increase by one
 	movlw	.1
+	;bra	incf_ext_flash_address0_0x20
 
+
+; increase flash address by value in WREG with roll-over at 0x200000 to 0x000000
+;
 	global	incf_ext_flash_address0_0x20
-incf_ext_flash_address0_0x20:				; with roll-over at 0x200000 to 0x000000
+incf_ext_flash_address0_0x20:
 	addwf	ext_flash_address+0,F			; increase address
 	movlw	d'0'
 	addwfc	ext_flash_address+1,F
 	addwfc	ext_flash_address+2,F
 	movlw	0x20
 	cpfseq	ext_flash_address+2				; at address 0x200000?
-	return									; No, return
+	return									; NO  - return
 ;	clrf	ext_flash_address+0
 ;	clrf	ext_flash_address+1
-	clrf	ext_flash_address+2				; Yes, rollover to 0x000000
+	clrf	ext_flash_address+2				; YES - rollover to 0x000000
 	return
 
 
+; decrease flash address by value in WREG
+;
 	global	decf_ext_flash_address0
 decf_ext_flash_address0:
 	subwf	ext_flash_address+0,F			; decrease address: do a 16-8bits subtract
@@ -62,157 +76,157 @@
 	subwfb	ext_flash_address+1,F
 	movlw	d'0'
 	subwfb	ext_flash_address+2,F
-	btfss	ext_flash_address+2,7			; Rollover to 0xFFFFFF?
-	return									; No, return
-	clrf	ext_flash_address+2				; Set to 0x00FFFFF
+	btfss	ext_flash_address+2,7			; under-run?
+	return									; NO  - return
+	clrf	ext_flash_address+2				; YES - set to 0x00FFFFF
 	setf	ext_flash_address+1
 	setf	ext_flash_address+0
 	return
 
 
-	global	ext_flash_byte_read_plus		; Return data read in WREG and SSP2BUF and 
+	global	ext_flash_byte_read_plus		; return data read in WREG and SSP2BUF and
 ext_flash_byte_read_plus:					; increase address after read
 	rcall	ext_flash_byte_read
 	movwf	ext_flash_rw					; store received data
 	bra		incf_ext_flash_address_p1		; +1 and return
 
 
-	global	ext_flash_byte_read_plus_0x20	; Return data read in WREG and SSP2BUF and 
+	global	ext_flash_byte_read_plus_0x20	; return data read in WREG and SSP2BUF and 
 ext_flash_byte_read_plus_0x20:				; increase address after read with banking at 0x200000
 	rcall	ext_flash_byte_read
 	movwf	ext_flash_rw					; store received data
-	bra		incf_ext_flash_address0_p1_0x20	;+1 and return
+	bra		incf_ext_flash_address0_p1_0x20	; +1 and return
 
 
-	global	ext_flash_byte_read				; Return data read in WREG
+	global	ext_flash_byte_read				; return data read in WREG
 ext_flash_byte_read:
-	movlw	0x03							; Read command
+	movlw	0x03							; read command
 	rcall	write_spi
-	rcall	ext_flash_write_address			; Write 24bit address ext_flash_address:3 via SPI
-	rcall	write_spi						; Dummy write to read data into WREG
+	rcall	ext_flash_write_address			; write 24 bit address ext_flash_address:3 via SPI
+	rcall	write_spi						; dummy write to read data into WREG
 	bsf		flash_ncs						; CS=1
 	movwf	ext_flash_rw
-	return									; Return data read in WREG and ext_flash_rw
+	return									; return data read in WREG and ext_flash_rw
 
 
-ext_flash_write_address:					; Write 24bit address ext_flash_address:3 via SPI
-	movf	ext_flash_address+2,W			; 24Bit Address
+ext_flash_write_address:					; write 24 bit address ext_flash_address:3 via SPI
+	movf	ext_flash_address+2,W			; 24 bit address
 	rcall	write_spi
 	movf	ext_flash_address+1,W
 	rcall	write_spi
 	movf	ext_flash_address+0,W
-	bra 	write_spi						; And return....
+	bra 	write_spi						; and return....
 
 
-	global	ext_flash_read_block_start		; Return data read in WREG
+	global	ext_flash_read_block_start		; return data read in WREG
 ext_flash_read_block_start:
-	movlw	0x03							; Read command
+	movlw	0x03							; read command
 	rcall	write_spi
-	rcall	ext_flash_write_address			; Write 24bit address ext_flash_address:3 via SPI
-	rcall	write_spi						; Dummy write to read data into WREG
-	return									; Return data read in WREG
+	rcall	ext_flash_write_address			; write 24 bit address ext_flash_address:3 via SPI
+	rcall	write_spi						; dummy write to read data into WREG
+	return									; return data read in WREG
 
 
-	global	ext_flash_read_block			; Return data read in WREG
+	global	ext_flash_read_block			; return data read in WREG
 ext_flash_read_block:
-	rcall	incf_ext_flash_address_p1		; Increase address +1
-	bra		write_spi1						; Dummy write to read data into WREG and return
+	rcall	incf_ext_flash_address_p1		; increase address +1
+	bra		write_spi1						; dummy write to read data into WREG and return
 
 
-	global	ext_flash_read_block_stop		; Return data read in WREG
+	global	ext_flash_read_block_stop		; return data read in WREG
 ext_flash_read_block_stop:
 	bsf		flash_ncs						; CS=1
-	return									; NO data in WREG
+	return									; nO data in WREG
 
 
 	global	write_byte_ext_flash_plus_header
-write_byte_ext_flash_plus_header:			; Write from WREG and increase address after write
+write_byte_ext_flash_plus_header:			; write from WREG and increase address after write
 	movwf	ext_flash_rw					; store data
 	; test if write is done at first byte of 4kB block
 	; if yes -> delete 4kB block first
 	tstfsz	ext_flash_address+0				; at 0x00?
-	bra		write_byte_ext_flash_plus_h1	; No, normal Write
+	bra		write_byte_ext_flash_plus_h1	; NO - normal write
 	movf	ext_flash_address+1,W
-	andlw	0x0F							; Mask lower nibble
+	andlw	0x0F							; mask lower nibble
 	tstfsz	WREG							; at 0x.0?
-	bra		write_byte_ext_flash_plus_h1	; No, normal Write
-	; At beginning of 4kB block -> erase first!
-	rcall	ext_flash_erase4kB				; Erases 4kB sector @ext_flash_address:3
+	bra		write_byte_ext_flash_plus_h1	; NO  - normal write
+											; YES - at beginning of 4kB block -> erase first!
+	rcall	ext_flash_erase4kB				;     - erases 4kB sector @ext_flash_address:3
 write_byte_ext_flash_plus_h1:
 	movf	ext_flash_rw,W
-	rcall	ext_flash_byte_write			; Write the byte
+	rcall	ext_flash_byte_write			; write the byte
 	bra		incf_ext_flash_address_p1		; +1 and return
 
 
-	global	write_byte_ext_flash_plus_nocnt	; No increase of ext_flash_dive_counter:3
+	global	write_byte_ext_flash_plus_nocnt	; no increase of ext_flash_dive_counter:3
 write_byte_ext_flash_plus_nocnt:
 	movwf	ext_flash_rw					; store data
 	bra		write_byte_ext_flash_plus2
 
 
-	global	write_byte_ext_flash_plus_nodel	; Does NOT delete 4kB Page when required
-write_byte_ext_flash_plus_nodel:			; Write from WREG and increase address after write with banking at 0x200000
+	global	write_byte_ext_flash_plus_nodel	; does NOT delete 4kB page when required
+write_byte_ext_flash_plus_nodel:			; write from WREG and increase address after write with banking at 0x200000
 	movwf	ext_flash_rw					; store data
-	bra		write_byte_ext_flash_plus1		; Ignore possible begin of 4kB page, there have been written 0xFF already
+	bra		write_byte_ext_flash_plus1		; ignore possible begin of 4kB page, there have been written 0xFF already
 
-	global	write_byte_ext_flash_plus		; Write from WREG and increase address after write with banking at 0x200000
+	global	write_byte_ext_flash_plus		; write from WREG and increase address after write with banking at 0x200000
 write_byte_ext_flash_plus:
 	movwf	ext_flash_rw					; store data
 	; First, increase dive length counter
 	incf	ext_flash_dive_counter+0,F
 	movlw	.0
 	addwfc	ext_flash_dive_counter+1,F
-	addwfc	ext_flash_dive_counter+2,F		; 24bit++
+	addwfc	ext_flash_dive_counter+2,F		; 24 bit ++
 
 write_byte_ext_flash_plus2:
 	; Now test if write is done at first byte of 4kB block
 	; if yes -> delete 4kB block first
 	tstfsz	ext_flash_address+0				; at 0x00?
-	bra		write_byte_ext_flash_plus1		; No, normal Write
+	bra		write_byte_ext_flash_plus1		; NO - normal write
 	movf	ext_flash_address+1,W
-	andlw	0x0F							; Mask lower nibble
+	andlw	0x0F							; mask lower nibble
 	tstfsz	WREG							; at 0x.0?
-	bra		write_byte_ext_flash_plus1		; No, normal Write
-	; At beginning of 4kB block -> erase first!
-	rcall	ext_flash_erase4kB				; Erases 4kB sector @ext_flash_address:3
+	bra		write_byte_ext_flash_plus1		; NO  - normal write
+											; YES - at beginning of 4kB block -> erase first!
+	rcall	ext_flash_erase4kB				;     - erases 4kB sector @ext_flash_address:3
 write_byte_ext_flash_plus1:
 	movf	ext_flash_rw,W
-	rcall	ext_flash_byte_write			; Write the byte
+	rcall	ext_flash_byte_write			; write the byte
 	bra		incf_ext_flash_address0_p1_0x20	; +1 and roll over at 0x200000 to 0x000000	and return
 
 
-	global	ext_flash_byte_write			; Write from WREG
+	global	ext_flash_byte_write			; write from WREG
 ext_flash_byte_write:
 	movwf	ext_flash_rw					; store data byte
 	bsf		flash_ncs						; CS=1
 	movlw	0x06							; WREN command
 	rcall	write_spi
 	bsf		flash_ncs						; CS=1
-	movlw	0x02							; Write (PP, Page-Program) command
+	movlw	0x02							; write (PP, Page-Program) command
 	rcall	write_spi
-	rcall	ext_flash_write_address			; Write 24bit address ext_flash_address:3 via SPI
+	rcall	ext_flash_write_address			; write 24 bit address ext_flash_address:3 via SPI
 	movf	ext_flash_rw,W					; load data byte
-	rcall	write_spi						; write one byte of data!
-	bra		ext_flash_wait_write			; And return...
+	rcall	write_spi						; write one byte of data
+	bra		ext_flash_wait_write			; and return...
 
 
-	global	ext_flash_byte_write_comms		; without wait, ~86us fixed delay due to 115200 Bauds
+	global	ext_flash_byte_write_comms		; without wait, ~86us fixed delay due to 115200 Baud
 ext_flash_byte_write_comms:
 	movwf	ext_flash_rw					; store data byte
 	bsf		flash_ncs						; CS=1
 	movlw	0x06							; WREN command
 	rcall	write_spi
 	bsf		flash_ncs						; CS=1
-	movlw	0x02							; Write (PP, Page-Program) command
+	movlw	0x02							; write PP (Page-Program) command
 	rcall	write_spi
-	rcall	ext_flash_write_address			; Write 24bit address ext_flash_address:3 via SPI
+	rcall	ext_flash_write_address			; write 24 bit address ext_flash_address:3 via SPI
 	movf	ext_flash_rw,W					; load data byte
-	rcall	write_spi						; write one byte of data!
+	rcall	write_spi						; write one byte of data
 	bsf		flash_ncs						; CS=1
 	return
 
 
-	global	ext_flash_disable_protection	; Disable write protection
+	global	ext_flash_disable_protection	; disable write protection
 ext_flash_disable_protection:
 	; unlock old memory
 	bsf		flash_ncs						; CS=1
@@ -221,7 +235,7 @@
 	bsf		flash_ncs						; CS=1
 	movlw	0x01							; WRSR command
 	rcall	write_spi
-	movlw	b'00000000'						; New status
+	movlw	b'00000000'						; new status
 	rcall	write_spi
 	bsf		flash_ncs						; CS=1
 	; unlock new memory
@@ -246,81 +260,82 @@
 	bsf		flash_ncs						; CS=1
 	return
 
+
 	global	ext_flash_enable_protection
 ext_flash_enable_protection:
 	; lock old memory
-	bsf		flash_ncs					; CS=1
-	movlw	0x50						; EWSR command
+	bsf		flash_ncs						; CS=1
+	movlw	0x50							; EWSR command
 	rcall	write_spi
-	bsf		flash_ncs					; CS=1
-	movlw	0x01						; WRSR command
+	bsf		flash_ncs						; CS=1
+	movlw	0x01							; WRSR command
 	rcall	write_spi
-	movlw	b'00011100'					; New status (Write protect on)
+	movlw	b'00011100'						; new status (write protection on)
 	rcall	write_spi
-	bsf		flash_ncs					; CS=1
+	bsf		flash_ncs						; CS=1
 	; lock new memory
-;	movlw	0x06						; WREN command
+;	movlw	0x06							; WREN command
 ;	rcall	write_spi
-;	bsf		flash_ncs					; CS=1
-;	movlw	0x8D						; LBPR command
+;	bsf		flash_ncs						; CS=1
+;	movlw	0x8D							; LBPR command
 ;	rcall	write_spi
-;	bsf		flash_ncs					; CS=1
-	movlw	0x06						; WREN command
+;	bsf		flash_ncs						; CS=1
+	movlw	0x06							; WREN command
 	rcall	write_spi
-	bsf		flash_ncs					; CS=1
-	movlw	0x42						; WBPR command
+	bsf		flash_ncs						; CS=1
+	movlw	0x42							; WBPR command
 	rcall	write_spi
 	movlw	.18
 	movwf	lo
 ext_flash_enable_protection2:
 	movlw	0xFF
 	rcall	write_spi
-	decfsz	lo,F						; 18 bytes with 0xFF
+	decfsz	lo,F							; 18 bytes with 0xFF
 	bra		ext_flash_enable_protection2
-	bsf		flash_ncs					; CS=1
+	bsf		flash_ncs						; CS=1
 	return
 
 
-	global	ext_flash_erase4kB			; Erases 4kB sector
+	global	ext_flash_erase4kB				; erases 4kB sector
 ext_flash_erase4kB:
-	bsf		flash_ncs					; CS=1
-	movlw	0x06						; WREN command
+	bsf		flash_ncs						; CS=1
+	movlw	0x06							; WREN command
 	rcall	write_spi
-	bsf		flash_ncs					; CS=1
-	movlw	0x20						; Sector erase command
+	bsf		flash_ncs						; CS=1
+	movlw	0x20							; sector erase command
 	rcall	write_spi
-	rcall	ext_flash_write_address		; Write 24bit address ext_flash_address:3 via SPI
-;	bra		ext_flash_wait_write		; Wait for write... and return
+	rcall	ext_flash_write_address			; write 24 bit address ext_flash_address:3 via SPI
+;	bra		ext_flash_wait_write			; wait for write... and return
 ext_flash_wait_write:
-	bsf		flash_ncs					; CS=1
-;	WAITMS	d'1'						; TBE/TSE=25ms...
-	movlw	0x05						; RDSR command
-	rcall	write_spi					; Read status
-	rcall	write_spi					; Read status into WREG
-	bsf		flash_ncs					; CS=1
-	btfsc	SSP2BUF,0					; Write operation in process?
-	bra		ext_flash_wait_write		; Yes, wait more..
+	bsf		flash_ncs						; CS=1
+;	WAITMS	d'1'							; TBE/TSE=25ms...
+	movlw	0x05							; RDSR command
+	rcall	write_spi						; read status
+	rcall	write_spi						; read status into WREG
+	bsf		flash_ncs						; CS=1
+	btfsc	SSP2BUF,0						; write operation in process?
+	bra		ext_flash_wait_write			; ES - loop waiting
 	return
 
 
-	global	ext_flash_erase_logbook		; erases logbook memory (000000h -> 2FFFFFh -> 3MByte -> 3145728 Bytes)
+	global	ext_flash_erase_logbook			; erases logbook memory (000000h -> 2FFFFFh -> 3MByte -> 3145728 Bytes)
 ext_flash_erase_logbook:
-	bsf		flash_ncs					; CS=1
+	bsf		flash_ncs						; CS=1
 	clrf	ext_flash_address+0
 	clrf	ext_flash_address+1
 	clrf	ext_flash_address+2
 
-	setf	ext_flash_rw				; 256*12kB=3145728 Bytes
+	setf	ext_flash_rw					; 256 * 12 kB = 3145728 bytes
 ext_flash_erase_logbook_loop:
-	rcall	ext_flash_erase4kB			; 4kB
-	rcall	ext_flash_add_4kB			; Increase ext_flash_address:3 by 4kB
-	rcall	ext_flash_erase4kB			; 4kB
-	rcall	ext_flash_add_4kB			; Increase ext_flash_address:3 by 4kB
-	rcall	ext_flash_erase4kB			; 4kB
-	rcall	ext_flash_add_4kB			; Increase ext_flash_address:3 by 4kB
-	decfsz	ext_flash_rw,F
-	bra		ext_flash_erase_logbook_loop
-	return
+	rcall	ext_flash_erase4kB				; 4kB
+	rcall	ext_flash_add_4kB				; increase ext_flash_address:3 by 4kB
+	rcall	ext_flash_erase4kB				; 4kB
+	rcall	ext_flash_add_4kB				; increase ext_flash_address:3 by 4kB
+	rcall	ext_flash_erase4kB				; 4kB
+	rcall	ext_flash_add_4kB				; increase ext_flash_address:3 by 4kB
+	decfsz	ext_flash_rw,F					; decrement loop counter, done?
+	bra		ext_flash_erase_logbook_loop	; NO  - loop
+	return									; YES - done
 
 ext_flash_add_4kB:
 	movlw	0x10
@@ -330,18 +345,18 @@
 	return
 
 
-write_spi:								; With data in WREG...
-	bcf		flash_ncs					; CS
+write_spi:									; with data in WREG...
+	bcf		flash_ncs						; CS
 	global	write_spi1
-write_spi1:								; With data in WREG...
-	bcf		SSP2STAT,WCOL				; Clear flag
-	movwf	SSP2BUF						; Write to buffer
-	btfsc	SSP2STAT,WCOL				; Was buffer full?
-	bra		write_spi1					; Yes, try again
-write_spi2:								; Wait for write command
-	btfss	SSP2STAT, BF				; Buffer full?
-	bra		write_spi2					; No, wait.
-	movf	SSP2BUF,W
-	return								; Returns RX data in WREG and SSP2BUF
+write_spi1:									; with data in WREG...
+	bcf		SSP2STAT,WCOL					; clear flag
+	movwf	SSP2BUF							; write to buffer
+	btfsc	SSP2STAT,WCOL					; was buffer full?
+	bra		write_spi1						; YES - try again
+write_spi2:									; wait for write command
+	btfss	SSP2STAT, BF					; buffer full?
+	bra		write_spi2						; NO  - loop waiting
+	movf	SSP2BUF,W						; YES - copy RX data to WREG
+	return									;     - return with RX data in WREG and SSP2BUF
 
 	END