#include SCL EQU 0x0020 ; I2C line setup SDA EQU 0x0010 D1 EQU 3965 ; correction const for TEMP C2 EQU 5871300 ; correction const for HUMI C1 EQU 14939840 ; -"- ; SHT15 interface adr command r/w MEASURE_TEMP EQU 0x03 ; 000 0001 1 MEASURE_HUMI EQU 0x05 ; 000 0010 1 STATUS_REG_W EQU 0x06 ; 000 0011 0 STATUS_REG_R EQU 0x07 ; 000 0011 1 RESET_SEN EQU 0x1e ; 000 1111 0 ;------------------------------------------------------------------------------ ORG 0A000h ; program start for MSP430F4260 ;------------------------------------------------------------------------------ RESET mov.w #300h, SP ; initialize stack pointer mov.w #WDTPW+WDTHOLD, &WDTCTL ; stop WDT bis.b #XCAP14PF, &FLL_CTL0 ; set load capacitance for xtal mov.b #LCDON + LCD3MUX + LCDFREQ_128, &LCDACTL ; 3-mux, ACLK/96 mov.b #0x0F, &LCDAPCTL0 ; assign s0-s13 to LCD bis.b #LCD2B, &LCDAVCTL0 ; 1/2 bias mode clr.b &P6OUT ; configure all pins for output mov.b #0xFF, &P6DIR clr.b &P5OUT mov.b #0x10, &P5DIR ; configure COM3 for output mov.b #0x0C, &P5SEL ; assign COM1 & COM2 pins to LCD clr.b &P1OUT ; preset SCL=0 and SDA=1 mov.b #0xEF, &P1DIR ; enable input at P1:4 mov.b #7, R15 ; 7 LCD memory bytes to clear clr.b LCDMEM-1(R15) ; clear display dec.b R15 jnz $-6 mov.b #0x27, &BTCTL ; basic timer1 setup ACLK/2^(16) clr.b &BTCNT1 ; clear counters clr.b &BTCNT2 bis.b #BTIE, &IE2 ; enable timer interrupt mov.w #3000, R15 ; 15ms power-on delay call #delay call #soft_reset_SHT15 mov.w #3000, R15 ; another 15ms delay is required call #delay ; after every soft reset of SHT15 call #start_SHT15 mov.b #STATUS_REG_W, R10 ; activate status reg for writing call #write_SHT15 mov.b #1, R10 ; set 12/8 bit T/H resolution call #write_SHT15 clr.w R7 ; start with measuring TEMP loop bit.b #BIT0, R7 ; measure TEMP if bit 0 of R7 is 0 jnz humi ; otherwise, measure HUMI temp call #get_TEMP1 ; request TEMP conversion clr.b &BTCNT1 mov.b #245, &BTCNT2 ; sleep for 80 msec bis.w #LPM3 | GIE, SR ; enter LPM3 mode (sleep) call #get_TEMP2 ; R10 = TEMP*100 call #temp2BCD ; compute BCD in R4 call #display ; display temp jmp sleep humi call #get_HUMI1 ; request HUMI conversion clr.b &BTCNT1 mov.b #253, &BTCNT2 ; sleep for 20 msec bis.w #LPM3 | GIE, SR ; enter LPM3 mode (sleep) call #get_HUMI2 ; R10 = HUMI call #humi2BCD ; compute BCD in R4 call #display ; display humi sleep xor.b #BIT0, R7 ; switch to the other mode bis.w #LPM3 | GIE, SR ; enter LPM3 mode (sleep) bis.w #LPM3 | GIE, SR ; do it again 3 times to acieve bis.w #LPM3 | GIE, SR ; a 8 sec delay between the bis.w #LPM3 | GIE, SR ; screen updates jmp loop ;//////////////////////////////////// procedures ; _____ ________ ; DATA: |_______| ; ___ ___ ; SCK : ___| |___| |______ start_SHT15 ; start condition for SHT15 bic.b #SDA, &P1DIR ; start with SDA=1 and SCL=0 bic.b #SCL, &P1OUT nop ; delay slot bis.b #SCL, &P1OUT ; set clock high bis.b #SDA, &P1DIR ; set dala low nop bic.b #SCL, &P1OUT ; set clock low jmp $+2 ; 5 us delay jmp $+2 nop bis.b #SCL, &P1OUT ; set clock high again nop bic.b #SDA, &P1DIR ; release data line nop bic.b #SCL, &P1OUT ; set clock low ret ; _____________________________________________________ ________ ; DATA: |_______| ; _ _ _ _ _ _ _ _ _ ___ ___ ; SCK : __| |__| |__| |__| |__| |__| |__| |__| |__| |______| |___| |______ reset_SHT15 ; reset sensor interface mov.b #9, R15 ; pulse counter bis.b #SCL, &P1OUT ; set clock high nop bic.b #SCL, &P1OUT ; ... and low dec.w R15 jnz $-16 call #start_SHT15 ret soft_reset_SHT15 call #reset_SHT15 mov.b #RESET_SEN, R10 call #write_SHT15 ret ;--------------------------------------------------------------------------- write_SHT15 ; write a byte in R10 to SHT15 bic.b #SDA, &P1DIR ; make sure that DATA=1 and CLK=0 bic.b #SCL, &P1OUT mov.b #8, R15 ; initialize bit counter w_loop rlc.b R10 ; get the leftmost data bit jc $+8 bis.b #SDA, &P1DIR ; set 0 on data line jnc $+8 bic.b #SDA, &P1DIR ; set 1 on data line bis.b #SCL, &P1OUT ; raise clock up jmp $+2 ; short delay jmp $+2 nop bic.b #SCL, &P1OUT ; ... and low dec.w R15 jnz w_loop ; repeat this 8 times bic.b #SDA, &P1DIR ; release the data line jmp $+2 ; let slave respond for ACK jmp $+2 jmp $+2 bis.b #SCL, &P1OUT ; clock up jmp $+2 ; slave responds OK (hopefully) bic.b #SCL, &P1OUT ; clock down ret ;--------------------------------------------------------------------------- read_SHT15 ; read byte from SHT15 in R10 bic.b #SDA, &P1DIR ; make sure that DATA=1 and CLK=0 bic.b #SCL, &P1OUT mov.b #8, R15 ; initialize bit counter r_loop bis.b #SCL, &P1OUT ; clock up bit.b #SDA, &P1IN ; received bit -> C-bit rlc.b R10 ; shift it into R10 bic.b #SCL, &P1OUT ; clock down nop dec.w R15 jnz r_loop ; repeat this 8 times tst.b R13 ; R13 = ACK jnz $+8 bis.b #SDA, &P1DIR ; send ACK signal bis.b #SCL, &P1OUT ; raise clock up jmp $+2 ; short delay jmp $+2 nop bic.b #SCL, &P1OUT ; ... and low bic.b #SDA, &P1DIR ; release the data line ret ;--------------------------------------------------------------------------- get_TEMP1 call #start_SHT15 ; measure TEMP mov.b #MEASURE_TEMP, R10 call #write_SHT15 ; send command to sensor ret get_TEMP2 bit.b #SDA, &P1IN ; wait for the end of measurement jnz $-6 clr.b R13 ; send ACK signal call #read_SHT15 ; get MSB in R10 mov.b R10, R11 ; and save it in R11 swpb R11 ; place MSB on its proper place inc.b R13 ; prapare to send NACK signal call #read_SHT15 ; get LSB in R10 add.w R11, R10 ; merge MSB and LSB in R10 rla.w R10 ; normalize TEMP so that rla.w R10 ; R10 = TEMP*100 sub.w #D1, R10 ; correct temp mov.w R10, R11 ; copy TEMP to R11 ret ;--------------------------------------------------------------------------- get_HUMI1 call #start_SHT15 ; measure relative humidity mov.b #MEASURE_HUMI, R10 call #write_SHT15 ; send command to sensor ret get_HUMI2 bit.b #SDA, &P1IN ; wait for the end of measurement jnz $-6 clr.b R13 ; send ACK signal call #read_SHT15 ; get MSB in R10 (not used) mov.b R10, R12 ; save MSB in R12 swpb R12 clr.w R12 ; MSB is not used in 8-bit mode inc.b R13 ; prapare to send NACK signal call #read_SHT15 ; get LSB in R10 add.w R12, R10 ; merge MSB and LSB mov.w R10, R12 ; copy HUMI value to R12 ret ;--------------------------------------------------------------------------- temp2BCD mov.w R10, R14 ; copy input number bit.w #BITF, R14 jz check_up inv.w R14 ; negate number if it is negative inc.w R14 cmp.w #1000, R14 ; display "-___" if TEMP is below jl check_up ; -9.9C mov #0xAAAA, R4 ret check_up cmp #10000, R14 ; exit if the number exceeds 9999 jl process mov #0xBBBB, R4 ; display "^^^^" ret process clr.w R4 ; storage for 4-digit BCD mov.b #16, R15 ; loop cnt = # of bits b2b_loop rla.w R14 ; use decimal addition dadd.w R4, R4 ; operation to convert R14 dec.b R15 ; into BCD jnz b2b_loop bit.w #BITF, R10 jz $+6 add.w #0xA000, R4 ; add the minus sign ret ;--------------------------------------------------------------------------- humi2BCD rla.w R10 rla.w R10 rla.w R10 rla.w R10 ; R10 = SO_RH*16 step1 ; linearization of HUMI by using a custom second degree polynomial mov.w #22934, R9 ; 22934 is two upper bytes of sub.w R10, R9 ; 5871300 swpb R9 mov.w R9, R8 and.w #0xFF00, R8 and.w #0x00FF, R9 add.w #196, R8 ; 196 = 5871300 mod 256; R9:R8 = add.w R10, R8 ; 5871300 - 4096*HUMI + 16*HUMI mov.w R12, R10 ; R10 = SO_RH clr.w R13 ; multiply R9:R8 by R12 and place clr.w R14 ; the result in R14:R13 mov.b #8, R15 ; counter setup mult_step1 rrc.b R12 jnc $+6 add.w R8, R13 ; add multiplicand to the result addc.w R9, R14 ; (32-bit operation) rla.w R8 ; shift the multiplicand rlc.w R9 dec.b R15 ; decrement the counter jnz mult_step1 ; and proceed sub.w #LWRD C1, R13 ; subtract C1 from R14:R13 subc.w #HWRD C1, R14 cmp.b #10, R10 ; process special cases of HUMI jeq $+8 cmp.b #11, R10 jne step2 sub.w #LWRD 10000000, R13 ; subtract 10^6 for HUMI=40 or 41 subc.w #HWRD 10000000, R14 ; R14:R13 = RH_lin*10^7 step2 ; temperature compensation of the HUMI value mov.w R11, R8 ; R11 = TEMP*100 clr.w R9 sub.w #2500, R8 ; R8 = TEMP*100 - 2500 subc.w #0, R9 ; R9:R8 = sign extended R8 swpb R10 ; R10 = SO_RH = HUMI clrc rrc.w R10 ; R10 = HUMI*128 add.w #1000, R10 ; R10 = 1000 + HUMI*128 mov.b #16, R15 ; setup for 16x16 multiplication clr.w R5 ; of R9:R8 by R10 clr.w R4 ; R5:R4 is the result mult_step2 rrc.w R10 jnc $+6 add.w R8, R4 addc.w R9, R5 rla.w R8 rlc.w R9 dec.b R15 jnz mult_step2 add.w R4, R13 ; add temp comp term to R14:R13 addc.w R5, R14 ; R14:R13 = RT_true*10^7 bit.w #BITF, R14 ; if the resulting value is < 0 jz $+8 ; replace it with 1 mov.w #0x100, R4 ret mov.w #-1, R10 div107 inc.w R10 ; divide R14:R13 by 10^7 sub.w #LWRD 10000000, R13 ; R10 is the integer part subc.w #HWRD 10000000, R14 ; of the resulting humidity jge div107 cmp.b #100, R10 ; if the value exceeds 100 jl $+8 ; replace it with 99 in BCD mov.w #0x0990, R4 ret clr.w R4 ; storage for 4-digit BCD mov.b #8, R15 ; loop cnt = # of bits b2b_loop2 rla.b R10 ; use decimal addition dadd.b R4, R4 ; operation to convert R10 dec.b R15 ; into BCD jnz b2b_loop2 rla.w R4 rla.w R4 rla.w R4 rla.w R4 ret ;--------------------------------------------------------------------------- display swpb R4 ; display BCD in R4 mov.b R4, R14 mov.b R4, R15 swpb R4 ; restore R4 rrc.b R14 rrc.b R14 rrc.b R14 and.b #0x1e, R14 add.w #digit1, R14 ; R14 = address of the 1st digit and.b #0x0F, R15 rla.b R15 add.w #digit2, R15 ; R15 = address of the 2nd digit mov.b @R14+, &LCDM1 ; load the 1st digit mov.b @R14, &LCDM4 ; and clean the place for the 2nd add.b @R15+, &LCDM1 ; load the 2nd digit mov.b @R15, &LCDM5 mov.b R4, R14 ; extract the 3rd digit rrc.b R14 rrc.b R14 rrc.b R14 and.b #0x1e, R14 mov.b R14, R15 clrc rrc.b R15 add R15, R14 ; R14 *= 3 add #digit3, R14 ; R14 = address of the 3rd digit mov.b @R14+, &LCDM7 ; load the 3rd digit and the mov.b @R14+, &LCDM6 ; trailing letter C mov.b @R14, &LCDM2 bit.b #BIT0, R7 ; postprocessing jz end_disp xor.b #0x70, &LCDM6 ; change letter from C to H xor.b #0x50, &LCDM2 bit.w #0x0F00, R4 ; turn off leading 0 for HUMI jnz $+12 clr.b &LCDM5 bic.b #0xF0, &LCDM1 ret end_disp bis.b #BIT5, &LCDM1 ; turn on decimal point ret ;--------------------------------------------------------------------------- delay dec.w R15 ; the delay loop takes 5 CPU cycles nop tst.w R15 jnz delay ret ;-------------------------------------------------------------------------- digit1 DW 0 ; do not display leading 0 ;DW 0x3505 ; digit 0 DW 0x0005 ; digit 1 DW 0x7401 ; digit 2 DW 0x7005 ; digit 3 DW 0x4105 ; digit 4 DW 0x7104 ; digit 5 DW 0x7504 ; digit 6 DW 0x1005 ; digit 7 DW 0x7505 ; digit 8 DW 0x7105 ; digit 9 DW 0x4000 ; the "-" symbol DW 0x1000 ; the "^" symbol digit2 DW 0x3550 ; digit 0 DW 0x0050 ; digit 1 DW 0x7410 ; digit 2 DW 0x7050 ; digit 3 DW 0x4150 ; digit 4 DW 0x7140 ; digit 5 DW 0x7540 ; digit 6 DW 0x1050 ; digit 7 DW 0x7550 ; digit 8 DW 0x7150 ; digit 9 DW 0x2000 ; the "_" symbol DW 0x1000 ; the "^" symbol digit3 DB 0x35 ; digit 0 (LCDM7 part for C) DB 0x35 ; digit 0 (LCDM6 part for C) DB 0x05 ; digit 0 (LCDM2 part for C) DB 0x05 ; digit 1 (LCDM7 part for C) DB 0x30 ; digit 1 (LCDM6 part for C) DB 0x05 ; digit 1 (LCDM2 part for C) DB 0x75 ; digit 2 (LCDM7 part for C) DB 0x34 ; digit 2 (LCDM6 part for C) DB 0x01 ; digit 2 (LCDM2 part for C) DB 0x75 ; digit 3 (LCDM7 part for C) DB 0x30 ; digit 3 (LCDM6 part for C) DB 0x05 ; digit 3 (LCDM2 part for C) DB 0x45 ; digit 4 (LCDM7 part for C) DB 0x31 ; digit 4 (LCDM6 part for C) DB 0x05 ; digit 4 (LCDM2 part for C) DB 0x75 ; digit 5 (LCDM7 part for C) DB 0x31 ; digit 5 (LCDM6 part for C) DB 0x04 ; digit 5 (LCDM2 part for C) DB 0x75 ; digit 6 (LCDM7 part for C) DB 0x35 ; digit 6 (LCDM6 part for C) DB 0x04 ; digit 6 (LCDM2 part for C) DB 0x15 ; digit 7 (LCDM7 part for C) DB 0x30 ; digit 7 (LCDM6 part for C) DB 0x05 ; digit 7 (LCDM2 part for C) DB 0x75 ; digit 8 (LCDM7 part for C) DB 0x35 ; digit 8 (LCDM6 part for C) DB 0x05 ; digit 8 (LCDM2 part for C) DB 0x75 ; digit 9 (LCDM7 part for C) DB 0x31 ; digit 9 (LCDM6 part for C) DB 0x05 ; digit 9 (LCDM2 part for C) DB 0x25 ; the "_" symbol (LCDM7 & C) DB 0x30 ; the "_" symbol (LCDM6 & C) DB 0x00 ; the "_" symbol (LCDM2 & C) DB 0x15 ; the "^" symbol (LCDM7 & C) DB 0x30 ; the "^" symbol (LCDM6 & C) DB 0x00 ; the "^" symbol (LCDM2 & C) ;--------------------------------------------------------------------------- bt1_ISR bic.w #LPM3, 0(SP) ; return from sleep reti ;------------------------------------------------------------------------------ ; Interrupt Vectors ;------------------------------------------------------------------------------ ORG 0x0FFE0 ; basic timer 1 vector DW bt1_ISR ORG 0x0FFFE ; RESET Vector DW RESET ; END