.include "m8def.inc" .equ OE =0b00001000 ; bit 3 Port D .equ RS =0b00000100 ; bit 2 Port D .equ temp_H =0x60 ;младший адрес принятой информации .equ temp_L =0x61 ;метка .equ abs_temp =0x62 .equ polov =0x63 .equ disp_stat =0x64 .equ navod =0x65 .equ action =0x66 .equ blim =0x67 .equ HU =0x68 .equ MU =0x69 .equ HU1 =0x6A .equ MU1 =0x6B .equ HU2 =0x6C .equ MU2 =0x6D .equ UST =0x6E .equ hour_H =0x70 .equ hour_L =0x71 .equ min_H =0x72 .equ min_L =0x73 .equ sec_H =0x74 .equ sec_L =0x75 .equ hour_H1 =0x76 .equ hour_L1 =0x77 .equ min_H1 =0x78 .equ min_L1 =0x79 .equ hour_H2 =0x7A .equ hour_L2 =0x7B .equ min_H2 =0x7C .equ min_L2 =0x7D .equ temp_1 =0x7E .equ temp_2 =0x7F .set DQ =2 .def DELAY3 =r7 ; .def DELAY1 =r8 ; To generate long delays .def DELAY2 =r9 ; .def temp =r16 ; temporary working register .def temp2 =r17 .def param =r18 ; Parameter transfer register .def wreg =R19 ;General use working register .def timeout =R20 ;Timeout value passed to subroutine .def ioreg =R21 ;Register for reading/writing DS1820 .def loopcnt =R22 ;Loop counter for serial read/write .def fbin =r16 ;8-bit binary value .def tBCDL =r16 ;BCD result MSD .def tBCDH =r17 ;BCD result LSD ;***** Port pin definitions .equ dsio =2 ;I/O pin connected to PB3 .equ T0PRE =0b00000010 ;Timer 0 prescaler 4MHz / 8 = 2uS tim0_ovf: ;вектор переполнение таймера счетчика 0 set ;Set T flag ldi wreg,0 ;Timer 0 off out TCCR0,wreg ;Stop timer reti ;Done, return reti temp_conv: rcall resetds ;Reset DS1820 device brts present ;Device found rjmp ex_temp_conv present: ldi ioreg,0xCC ;Skip ROM command rcall writeds ldi ioreg,0x44 ;Convert T command rcall writeds twait: rcall readds ;Check for conversion complete tst ioreg ;Returns all zeros while busy breq twait rcall resetds ;Reset again ldi ioreg,0xCC ;Skip ROM command rcall writeds ldi ioreg,0xBE ;Read scratchpad command rcall writeds rcall readds ;Read temperature LSB sts temp_L,ioreg ;Store reading rcall readds ;Read temperature MSB sts temp_H,ioreg ;Store reading rcall resetds ;Don't read the rest ldi loopcnt,255 pause: ldi timeout,6 rcall delay dec loopcnt brne pause ex_temp_conv: ret ;***** Write a byte to the DS1820 writeds: ldi loopcnt,8 ;Send 8 bits to device wrloop: sbi DDRB,dsio ;Make I/O pin an output cbi PORTB,dsio ;Pull I/O pin low ldi timeout,-1 ;Make timer 0 count 2uS rcall delay ror ioreg ;Get bit into carry brcc wrzero ;If clear, leave line low sbi PORTB,dsio ;Otherwise pull line high wrzero: ldi timeout,-30 ;Make timer 0 count 30 * 2uS rcall delay sbi PORTB,dsio ;Pull line back high ldi timeout,-1 ;Make timer 0 count 2uS rcall delay dec loopcnt ;Decrement bit counter brne wrloop ;Loop for all 8 bits ret ;***** Read a byte from the DS1820 readds: ldi loopcnt,8 ;Get 8 bits from device ldi ioreg,0 ;Clear holding register rdloop: sbi DDRB,dsio ;Make I/O pin an output cbi PORTB,dsio ;Pull I/O pin low ldi timeout,-1 ;Make timer 0 count 2uS rcall delay cbi DDRB,dsio ;Make I/O pin an input, will pull up high ldi timeout,-2 ;Make timer 0 count 2 * 2uS rcall delay ;Give pin time to go high if needed clc ;clear carry, assume bit is a zero sbic PINB,dsio ;Check I/O pin sec ;Set carry if pin was high ror ioreg ;Get bit into register ldi timeout,-29 ;Make timer 0 count 29 * 2uS rcall delay ;Fill out time slot dec loopcnt ;Decrement bit counter brne rdloop ;Loop for all 8 bits ret ;***** Reset DS1820 and read presence pulse, return result in T resetds: sbi DDRB,dsio ;Make I/O pin an output cbi PORTB,dsio ;Pull I/O pin low ldi timeout,6 ;Make timer 0 count 250 * 2uS rcall delay sbi PORTB,dsio ;Pull I/O pin high cbi DDRB,dsio ;Make I/O pin an input ldi timeout,-45 ;Make timer 0 count 45 * 2uS rcall delay clt ;Assume device not present sbis PINB,dsio ;Check for presence pulse set ;Indicate result in T ldi timeout,6 ;Make timer 0 count 250 * 2uS rcall delay ret ;***** Delay n*2 microseconds using timer 0, delay time passed in timeout delay: in wreg,SREG ;Save status register push wreg out TCNT0,timeout clt ;Clear T ldi wreg,T0PRE ;Timer 0 prescaler out TCCR0,wreg ;Run timer dwait: brtc dwait ;Wait for timer 0 interrupt to set T pop wreg ;Restore status register out SREG,wreg ret