;******************************************************************************* ; MSP430F20x2 Demo - ADC10, Sample A10 Temp and Convert to oC and oF ; ; Description: A single sample is made on A10 with reference to internal ; 1.5V Vref Software sets ADC10SC to start sample and conversion - ADC10SC ; automatically cleared at EOC ADC10 internal oscillator/4 times sample ; (64x) and conversion In Mainloop MSP430 waits in LPM0 to save power until ; ADC10 conversion complete, ADC10_ISR will force exit from any LPMx in ; Mainloop on reti Result is converted to Temperature represented as ; BCD 0000 - 0145 representing oC saved at 0200h and 0000 - 0292 representing ; oF saved at 0202h Temperature sensor offset and slope will vary from device ; to device per datasheet tolerance ; Uncalibrated temperature measured from device to devive will vary with ; slope and offset - please see datasheet ; ACLK = n/a, MCLK = SMCLK = default DCO ~1.2MHz, ADC10CLK = ADC10OSC/4 ; ; MSP430F20x2 ; ; /|\| XIN|; | | | ; |RST XOUT|; | | ; |A10 | ; ; L Westlund ; Texas Instruments Inc ; May 2006 ; Built with IAR Embedded Workbench Version: 3.41A ;******************************************************************************* #include "msp430x20x2.h" ; RSEG CSTACK ; Define stack segment ; RSEG CODE ; Assemble to Flash memory ; RESET mov.w #SFE(CSTACK),SP ; Initialize stackpointer StopWDT mov.w #WDTPW+WDTHOLD,&WDTCTL ; Stop WDT SetupADC10 mov.w #INCH_10+ADC10DIV_3,&ADC10CTL1 ; Temp Sensor ADC10CLK/4 mov.w #SREF_1+ADC10SHT_3+REFON+ADC10ON+ADC10IE,&ADC10CTL0 ; mov.w #30,&TACCR0 ; Delay to allow Ref to settle bis.w #CCIE,&TACCTL0 ; Compare-mode interrupt mov.w #TACLR+MC_1+TASSEL_2,&TACTL; up mode, SMCLK bis.w #LPM0+GIE,SR ; Enter LPM0, enable interrupts bic.w #CCIE,&TACCTL0 ; Disable timer interrupt dint ; ; Mainloop bis.w #ENC+ADC10SC,&ADC10CTL0 ; Start sampling/conversion bis.w #CPUOFF+GIE,SR ; LPM0, ADC10_ISR will force exit call #Trans2TempC ; Transform voltage to temperature call #BIN2BCD4 ; R13 = TempC = 0000 - 0145 BCD mov.w R13,&0200h ; 0200h = temperature oC call #Trans2TempF ; Transform voltage to temperature call #BIN2BCD4 ; R13 = TempF = 0000 - 0292 BCD mov.w R13,&0202h ; 0202h = temperature oF jmp Mainloop ; Packed 4- digit BCD R13 ; Input: R12 0000 - 0FFFh, R15 working register ; Output: R13 0000 - 4095 ; mov.w #16,R15 ; Loop Counter clr.w R13 ; -> RESULT LSD BIN1 rla.w R12 ; Binary MSB to carry dadd.w R13,R13 ; RESULT x2 LSD dec.w R15 ; Through? jnz BIN1 ; Not through ret ; ; ; MPYU ; Unsigned Multipy R11 x R12 = R15|R14 ; Input: R11, R12 R10 and R13 are working registers ; Output: R15, R14 ; clr.w R14 ; -> LSBs result clr.w R15 ; -> MSBs result MACU clr.w R13 ; MSBs multiplier mov.w #1,R10 ; bit test register MPY2 bit.w R10,R11 ; test actual bit jz MPY1 ; IF 0: nothing add.w R12,R14 ; IF 1: add multiplier to result addc.w R13,R15 ; MPY1 rla.w R12 ; multiplier x rlc.w R13 ; rla.w R10 ; next bit to test jnc MPY2 ; if bit in carry: finished ret ; Return from subroutine ; ; TA0_ISR; ISR for TACCR0 ; clr.w &TACTL ; Clear Timer_A control registers bic.w #LPM0,0(SP) ; Exit LPMx, interrupts enabled reti ; ; ADC10_ISR; ; bic.w #LPM0,0(SP) ; Exit LPM0 on reti reti ; ; ; COMMON INTVEC ; Interrupt Vectors ; ORG ADC10_VECTOR ; ADC10 Vector DW ADC10_ISR ORG TIMERA0_VECTOR ; Timer_A0 Vector DW TA0_ISR ORG RESET_VECTOR ; POR, ext Reset DW RESET END