$MOD51

dat10	equ 50h
dat11	equ 51h
dat12	equ 52h
dat13	equ 53h
dat14	equ 54h
dat15	equ 55h
dat16	equ 56h
dat17	equ 57h
dat18	equ 58h
dat19	equ 59h
dat20	equ 5Ah

crc	equ 5Bh

adr	equ R4

znak	equ R5

citac	equ R6
rtc_r	equ 74h
rtc_s	equ 75h

rtc_ts	equ 76h

SDA	bit P1.6
SCL	bit P1.7	;komunikace s I2C cipem
cpuiic	bit P1.5	;cistota sbernice


org 0
	ajmp rst

org 3
	reti

org 0bh
	reti

org 13h
	reti

org 1bh
	reti


; nastaveni serioveho portu na 9600b/s
rst:	
	mov	TMOD, #00100000B;
	MOV	TH1, #0FDh	;
	ANL	PCON, #7Fh	;
	MOV	SCON, #01000000B;
	SETB	TR1		;
	CLR	RI		;
	CLR	TI		;
	clr A
;	dec A		;perem do registru FF, jestli to funguje
	mov dat10,A
	mov dat11,A
	mov dat12,A
	mov dat13,A
	mov dat14,A
	mov dat15,A
	mov dat16,A
	mov dat17,A
	mov dat18,A
	mov dat19,A
	mov dat20,A

	setb SCL
	setb SDA	;zapisjem na port 1, pripravujem je na cteni

mloop:	
	jb SDA,mloop

;	mov A,P1
;	anl A,#11000000b
;	cjne A,#10000000b,mloop
;	jb SDA,mloop

	jnb SCL,mloop	;cekame na podminku START na sbernici IIC

	call shin	;zjisti co prislom je to v A
	cjne A,#11110000b,mloop	;je to pro mne? F0h?
	call ack

	call shin	;zjisti co prislom je to v A
	mov adr,A
	call ack

	call shin	;zjisti co prislom je to v A
	call ack

	call nak

stop:	jnb SDA,stop
	jnb SCL,stop	;cekame na podminku STOP na sbernici IIC

	cjne adr,#10,da10
	mov dat10,A
	ajmp mloop
da10:	cjne adr,#11,da11
	mov dat11,A
	ajmp mloop
da11:	cjne adr,#12,da12
	mov dat12,A
	ajmp mloop
da12:	cjne adr,#13,da13
	mov dat13,A
	ajmp mloop
da13:	cjne adr,#14,da14
	mov dat14,A
	ajmp mloop
da14:	cjne adr,#15,da15
	mov dat15,A
	ajmp mloop
da15:	cjne adr,#16,da16
	mov dat16,A
	ajmp mloop
da16:	cjne adr,#17,da17
	mov dat17,A
	ajmp mloop
da17:	cjne adr,#18,da18
	mov dat18,A
	ajmp mloop
da18:	cjne adr,#19,da19
	mov dat19,A
zaca:	ajmp mloop
da19:	cjne adr,#20,da20
	mov dat20,A
da20:	
	clr A
	xrl A,dat10
	xrl A,dat11
	xrl A,dat12
	xrl A,dat13
	xrl A,dat14
	xrl A,dat15
	xrl A,dat16
	xrl A,dat17
	xrl A,dat18
	xrl A,dat19
	mov crc,A
	cjne A,dat20,zaca	;CRC shodne s tim co doslo?

	mov znak,#'$'
	call pism
	mov znak,#'T'
	call pism
	mov znak,dat10
	call pisme
	mov znak,dat11
	call pisme
	mov znak,dat12
	call pisme
	mov znak,dat13
	call pisme
	mov znak,dat14
	call pisme
	mov znak,dat15
	call pisme
	mov znak,dat16
	call pisme
	mov znak,dat17
	call pisme
	mov znak,dat18
	call pisme
	mov znak,dat19
	call pisme
;	mov znak,dat20
;	call pisme
;	mov znak,crc
;	call pisme

	mov znak,#13
	call pism	; Enter

	ajmp mloop

shin:
	; Shift in a byte from the AT24Cxx, most significant bit first.
	; SCL expected low on entry. Return with SCL low.
	; Returns received data byte in A.


	push	b
	mov	b, #8		; bit count
x43:	jb 	SCL,$
	jnb	SCL,$		; cekame na platne hodiny
	nop
	mov	C, SDA		; input bit
	rlc	a		; move bit into byte
	djnz	b, x43		; next bit

	pop	b
	ret
ACK:
	; Clock out an acknowledge bit (low).
	; SCL expected low on entry. Return with SCL, SDA low.


	jb	SCL,$		; cekame na 0
	clr	SDA		; ACK bit
	jnb	SCL,$		; cekame na 1
	nop
	nop
	setb SDA	;abychom mohli zase cist z portu
	ret

NAK: 	
	jb 	SCL,$
	jnb	SCL,$		; cekame na platne hodiny
	mov c,sda
	jb 	SCL,$
	jnb	SCL,$		; cekame na platne hodiny
	
	ret


pisme:	mov A,znak
	mov B,A
	rr	a
	rr	a
	rr	a
	rr	a
	call konv
	mov A,B
	
konv:	anl A,#0Fh
	add A,#30h
	cjne A,#3Ah,ne_A
	mov A,#41h	;A
ne_A:	cjne A,#3Bh,ne_B
	mov A,#42h	;B
ne_B:	cjne A,#3Ch,ne_C
	mov A,#43h	;C
ne_C:	cjne A,#3Dh,ne_D
	mov A,#44h	;D
ne_D:	cjne A,#3Eh,ne_E
	mov A,#45h	;E
ne_E:	cjne A,#3Fh,ne_F
	mov A,#46h	;F
ne_F:	mov znak,A
		
pism: 	mov A,znak		;vyslani znaku pres seriovy kanal
	MOV	SBUF, A		;
	JNB	TI, $		;
	nop
	nop
	CLR	TI		;
	ret

;stop:	jnb SCL,stop
	nop
	nop
	nop
	nop
;	jb SDA,stop	;cekame na podminku STOP na sbernici IIC

end