📄 fet410_sd16_06.s43
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;******************************************************************************
; MSP-FET430P410 Demo - SD16, Using the Integrated Temperature Sensor
;
; Description: This example shows how to use the SD16 module's integrated
; temperature sensor (connected to input channel 6) to measure temperature.
; A single conversion is initiated and then the CPU is disabled by entering
; LPM0. Once the conversion has completed, a SD16 interrupt occurs and
; stores the result in register R5. Next, the CPU wakes up and converts
; this value into two temperature values, one in degrees Celcius and one
; in degrees Farenheit. Test by setting a breakpoint at the line indicated
; below and running the program. Upon reaching the breakpoint, use the
; debugger's register window to view degrees C in register R11 and
; degrees F in register R9. Temperatures stored in R9 and R11 are in
; BCD format.
; ACLK = LFXT1 = 32768Hz, MCLK = SMCLK = default DCO = 32 x ACLK = 1048576Hz
; //* An external watch crystal between XIN & XOUT is required for ACLK *//
; //* Minimum Vcc is required for SD16 module - see datasheet *//
; //* 100nF cap btw Vref and AVss is recommended when using 1.2V ref *//
;
; Sensor's temperature coefficient is 1.32mV/K (from 'F42x datasheet)
; Sensor's offset voltage ranges from -100mv to 100mV (assume 0)
; DegC = DegK - 273
; DegF = (DegC * 9/5) + 32
; Vref = 1200mV
; Vsensor = 1.32mV * DegK + Vsensor_offset (assuming 0mv for offset)
; Vsensor = (SD16MEM2-32768)/32768 * Vref/2
; DegK = (SD16MEM2 - 32768)/65536 * 1200/1.36
; DegK = (SD16MEM2 * 909)/65536 - 454
; DegC = (SD16MEM2 * 909)/65536 - 727 ( No need to simplify further, )
; DegF = (SD16MEM2 * 1636)/65536 - 1276 ( take advantage of HW multiplier )
; ( and simple binary division )
;
; MSP430F427
; -----------------
; /|\| XIN|-
; | | | 32kHz
; --|RST XOUT|-
; | |
; |A2.6+ | ( A2.6+, A2.6- connected internally )
; |A2.6- | ( to SD16's temperature sensor )
; | |
; | VREF |---+
; | | |
; | | -+- 100nF
; | | -+-
; | | |
; | AVss |---+
; | |
;
; H. Grewal
; Texas Instruments, Inc
; February 2005
; Built with IAR Embedded Workbench Version: 3.21A
;******************************************************************************
#include <msp430x42x.h>
;-----------CPU Registers Used-------------------------------------------------
; R5 - SD12 CH2 conversion result
; R6 - Temporary working register
; R7 - Temporary working register
; R8 - Temporary working register
; R9 - Degrees Farenheit
; R10 - Temporary working register
; R11 - Degrees Centigrade
; R15 - Temporary working register
;------------------------------------------------------------------------------
ORG 08000h ; Program Start
;------------------------------------------------------------------------------
RESET mov #600h,SP ; Initialize stack pointer
StopWDT mov #WDTPW+WDTHOLD,&WDTCTL ; Stop WDT
SetupFLL bis.b #XCAP14PF,&FLL_CTL0 ; Configure load caps
mov #10000,R15 ;
Xtal_Wait dec R15 ; Delay for 32 kHz crystal to
jnz Xtal_Wait ; stabilize
SetupSD16 mov #SD16REFON+SD16SSEL0,&SD16CTL
; 1.2V ref, SMCLK
bis #SD16SNGL+SD16IE,&SD16CCTL2
; Single conv, enable interrupt
bis.b #SD16INCH_6,&SD16INCTL2 ; Select channel A2.6 connected to
; internal temperature sensor
mov #03600h,R15 ; Delay needed for 1.2V ref startup
L$1 dec R15 ;
jnz L$1 ;
eint ; Enable global interrupts
Mainloop bis #SD16SC,&SD16CCTL2 ; Start conversion
bis #CPUOFF,SR ; Enter LPM0 (disable CPU), wait
; for conversion to complete
Cmode mov.w R5,&MPY ; Multiply SD16 result by 909
mov.w #038Dh,&OP2 ; Load 909 in OP2 register
mov.w &RESHI,R11 ; Use R11 and disregard R10
mov.w &RESLO,R10 ; (end result is 8-bit right shift)
sub.w #02D7h,R11 ; Subtract 727 from R11
bin2bcdC ; Convert binary to BCD
mov #16,r15 ; Load loop counter
clr r6 ; Clear working register r6
clr r7 ; Clear working register r7
L$2 rla R11 ; Left-shift R11
dadd r7,r7 ; Decimally add src+dst+C
dadd r6,r6 ; Decimally add src+dst+C
dec r15 ; Decrement loop counter
jnz L$2 ; Is loop counter = 0?
mov r7,r11 ; Save DegC in BCD format in R11
Fmode mov.w R5,&MPY ; Multiply SD16 result by 1636
mov.w #0664h,&OP2 ; Load 1636 in OP2 register
mov.w &RESHI,R9 ; Use R9 and disregard R8
mov.w &RESLO,R8 ; (end result is 8-bit right shift)
sub.w #04FCh,R9 ; Subtract 1276 from R9
bin2bcdF
mov #16,r15 ; Load loop counter
clr r6 ; Clear working register r6
clr r7 ; Clear working register r7
L$3 rla R9 ; Left-shift R11
dadd r7,r7 ; Decimally add src+dst+C
dadd r6,r6 ; Decimally add src+dst+C
dec r15 ; Decrement loop counter
jnz L$3 ; Is loop counter = 0?
mov r7,r9 ; Save DegF in BCD format in R9
jmp Mainloop ; SET BREAKPOINT HERE
;
;------------------------------------------------------------------------------
SD16_ISR ; SD16 Interrupt Service Routine
;------------------------------------------------------------------------------
add.w &SD16IV,PC ; Add offset to PC
reti ; Vector 0: No interrupt
jmp SD_OV ; Vector 2: Overflow
jmp SD_CH0 ; Vector 4: CH0 IFG
jmp SD_CH1 ; Vector 6: CH1 IFG
; Vector 8: CH2 IFG
;
;-----------SD16 Channel 2 Interrupt Handler-----------------------------------
SD_CH2 mov &SD16MEM2,R5 ; Save CH2 conversion result
bic #CPUOFF,0(SP) ; Return active
SD_CH2_END reti ; Return from interrupt
;
;-----------SD16 Memory Overflow Interrupt Handler-----------------------------
SD_OV reti ; Return from interrupt
;
;-----------SD16 Channel 0 Interrupt Handler-----------------------------------
SD_CH0 reti ; Return from interrupt
;
;-----------SD16 Channel 1 Interrupt Handler-----------------------------------
SD_CH1 reti ; Return from interrupt
;
;------------------------------------------------------------------------------
COMMON INTVEC ; Interrupt Vectors
;------------------------------------------------------------------------------
ORG RESET_VECTOR ; RESET Vector
DW RESET ;
ORG SD16_VECTOR ; SD16 Vector
DW SD16_ISR ;
END
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