; OSTC Mk.2, 2N and 2C - diving computer code
; Copyright (C) 2015 HeinrichsWeikamp GbR

;    This program is free software: you can redistribute it and/or modify
;    it under the terms of the GNU General Public License as published by
;    the Free Software Foundation, either version 3 of the License, or
;    (at your option) any later version.

;    This program is distributed in the hope that it will be useful,
;    but WITHOUT ANY WARRANTY; without even the implied warranty of
;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;    GNU General Public License for more details.

;    You should have received a copy of the GNU General Public License
;    along with this program.  If not, see <http://www.gnu.org/licenses/>.


; internal EEPROM and RS232 UART interface
; written by: Matthias Heinrichs, info@heinrichsweikamp.com
; written: 02/01/06
; last updated: 090109
; known bugs:
; ToDo: 

write_int_eeprom	macro	eeprom_address
	movlw	eeprom_address
	call	write_int_eeprom_1
	endm

write_int_eeprom_1:
	movwf	EEADR
	bra		write_eeprom			; writes and "returns" after write

read_int_eeprom	macro	eeprom_address
	movlw	eeprom_address
	call	read_int_eeprom_1
	endm

read_int_eeprom_1:
	movwf	EEADR
	bra		read_eeprom					; reads and "returns" after write

internal_eeprom_access_b2:				; accesses internal EEPROM BANK 2 via the UART
	bcf		internal_eeprom_write3		; clear flag!
	movlw	d'2'
	movwf	EEADRH						;BANK2
	movlw	"n"
	bra		internal_eeprom_access1		; Continue with common routines

internal_eeprom_access_b1:				; accesses internal EEPROM BANK 1 via the UART
	bcf		internal_eeprom_write2		; clear flag!
	movlw	d'1'
	movwf	EEADRH						;BANK1
	movlw	"i"
	bra		internal_eeprom_access1		; Continue with common routines

internal_eeprom_access_b0:				; accesses internal EEPROM BANK 0 via the UART
	bcf		internal_eeprom_write		; clear flag!
	clrf	EEADRH						; Bank0
	movlw	"d"
;	bra		internal_eeprom_access1		; Continue with common routines
internal_eeprom_access1:
	movwf	TXREG						; Send command echo ("i", "d" or "n")
	bsf		no_sensor_int				; No Sensor Interrupt
	movlw	d'4'
	movwf	EEADR
	bcf		PIE1,RCIE					; no interrupt for UART
	bcf		PIR1,RCIF					; clear flag
	bsf		LED_blue					; LEDusb ON

internal_eeprom_access2:
	rcall	rs232_get_byte				; Get byte to write...
	movff	RCREG,EEDATA				; copy to write register
	bsf		LED_red						; show activity

	btfsc	rs232_recieve_overflow		; overflow recieved?
	bra		internal_eeprom_access3		; Yes, abort!

	rcall	write_eeprom				; No, write one byte
	bcf		LED_red
	movff	EEDATA,TXREG				; Send echo!
	rcall	rs232_wait_tx				; Wait for UART
	incfsz 	EEADR,F						; Do until EEADR rolls to zero
	bra		internal_eeprom_access2
internal_eeprom_access2a:
	bcf		LED_blue					; LEDusb OFF
	bcf		PIR1,RCIF					; clear flag
	bsf		PIE1,RCIE					; re-enable interrupt for UART
	clrf	EEADRH						; Point to Bank0 again
	bcf		rs232_recieve_overflow		; Clear Flag
	bcf		no_sensor_int				; Renable Sensor Interrupt
	goto	restart

internal_eeprom_access3:				; Overflow! Abort writing
	movlw	0xFF
	movwf	TXREG						; Error Byte
	bra		internal_eeprom_access2a	; Quit

read_eeprom: 							; reads from internal eeprom
	bcf		EECON1,EEPGD
	bcf		EECON1,CFGS
	bsf		EECON1,RD
	return

write_eeprom:							; writes into internal eeprom
	bcf		EECON1,EEPGD
	bcf		EECON1,CFGS
	bsf		EECON1,WREN

	bcf		INTCON,GIE					; even the RTC will be delayed for the next 5 instructions...
	movlw	0x55		
	movwf	EECON2
	movlw	0xAA
	movwf	EECON2
	bsf		EECON1,WR
	bsf		INTCON,GIE					; ...but the flag for the ISR routines were still set, so they will interrupt now!

write_eep2:
	btfsc	EECON1,WR		
	bra 	write_eep2					; wait about 4ms...
	bcf		EECON1,WREN
	return

enable_rs232:				;IO Ports must be input in order to activate the module
	bsf		TRISC,6			; TX Pin
	bsf		TRISC,7			; RX Pin

	movlw	b'00100100'			; BRGH=1
	movwf	TXSTA
	movlw	b'10010000'
	movwf	RCSTA
	movlw	b'00001000'
	movwf	BAUDCON
	clrf	SPBRGH
	movlw	SPBRG_VALUE			; Take care of the baud rate when changing Fosc!
	movwf	SPBRG
	clrf	RCREG
	clrf	PIR1
	bsf		PIE1,RCIE			; enable interrupt for RS232
	return

disable_rs232:
	clrf	TXSTA
	clrf	RCSTA
	bcf		PIE1,RCIE			; disable interrupt for RS232
	bcf		TRISC,6			; TX Pin
	bcf		TRISC,7			; RX Pin
	bcf		PORTC,6			; TX Pin
	bcf		PORTC,7			; RX Pin
	return

rs232_wait_tx:
	btfss	RCSTA,SPEN			; Transmitter active?
	return						; No, return!
	nop
	btfss	TXSTA,TRMT			; RS232 Busy?
	bra		rs232_wait_tx		; yes, wait...
	return						; Done.


rs232_get_byte:
	bcf		PIR1,RCIF		; clear flag
	bcf		rs232_recieve_overflow		; clear flag
	clrf 	uart1_temp
rs232_get_byte2:
	clrf 	uart2_temp
rs232_get_byte3:
	btfsc 	PIR1,RCIF		; data arrived?
	return					; data received

	nop						; Wait 1us * 255 * 255 = 65ms+x Timeout/Byte
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	btfsc 	PIR1,RCIF		; data arrived?
	return	
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	btfsc 	PIR1,RCIF		; data arrived?
	return	
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	btfsc 	PIR1,RCIF		; data arrived?
	return	
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	btfsc 	PIR1,RCIF		; data arrived?
	return	

	decfsz 	uart2_temp,F
	bra 	rs232_get_byte3
	decfsz 	uart1_temp,F
	bra		rs232_get_byte2
						; timeout occoured (about 20ms)
	bcf		RCSTA,CREN		; Clear receiver status
	bsf		RCSTA,CREN
	bsf		rs232_recieve_overflow		; set flag
	return				; and return anyway

uart_115k_bootloader:
	bcf		PIE1,RCIE				; disable interrupt for RS232
	call	DISP_ClearScreen		; Clear screen
	movlw	color_red
    call	DISP_set_color			; Set to Red
	DISPLAYTEXTH	d'302'			; Bootloader
	bcf		RCSTA,CREN				; Clear receiver status
	bsf		RCSTA,CREN
	bcf		PIR1,RCIF				; clear flag
	movlw	d'200'					; one second
	movwf	uart1_temp
uart_115k_bootloader0:
	btfsc	PIR1,RCIF				; New byte in UART?
	bra		uart_115k_bootloader1	; Yes, Check if 0xC1
	WAITMS	d'5'
	decfsz	uart1_temp,F
	bra		uart_115k_bootloader0
uart_115k_bootloader2:
	DISPLAYTEXTH	d'304'			; Aborted!
	movlw	d'8'					; Two seconds
	movwf	uart1_temp
uart_115k_bootloader3:
	WAITMS	d'250'
	decfsz	uart1_temp,F
	bra		uart_115k_bootloader3
	goto	restart
	
uart_115k_bootloader1:
	movlw	0xC1
	cpfseq	RCREG					; 115200Baud Bootloader request?
	bra		uart_115k_bootloader2	; No, Abort

; Vault date and time during update
; EEPROM Bank1
; Byte 5: =0xAA -> reload time and date in "restart:"
; Byte 6-11: YYMMDDHHMMSS
    movlw   .1
    movwf   EEADRH
    movff   year,EEDATA
    write_int_eeprom	d'6'
    movff   month,EEDATA
    write_int_eeprom	d'7'
    movff   day,EEDATA
    write_int_eeprom	d'8'
    movff   hours,EEDATA
    write_int_eeprom	d'9'
    movff   mins,EEDATA
    write_int_eeprom	d'10'
    movff   secs,EEDATA
    write_int_eeprom	d'11'
    movlw   0xAA
    movwf   EEDATA
    write_int_eeprom	d'5'        ; Set flag
    clrf    EEADRH
	DISPLAYTEXTH	d'303'			; Yes, "Please wait!"
	clrf	INTCON					; Interrupts disabled
	bcf		PIR1,RCIF				; clear flag
	goto	0x17F56					; Enter straight into bootloader. Good luck!