TMP03/TMP04

REV. 0

–14–

Listing 2. Software Routine for the TMP04-to-ADSP-210x Interface

;

{ ADSP-21XX Temperature Measurement Routine

TEMPERAT.DSP

Altered Registers:

ax0, ay0, af, ar,

si, sr0,

my0, mr0, mr1, mr2.

Return value:

ar —> temperature result in 14.2 format

Computation time:

2 * TMP04 output period

}

.MODULE/RAM/BOOT=0

TEMPERAT;

{ Beginning TEMPERAT Program }

.ENTRY TEMPMEAS;

{ Entry point of this subroutine }

.CONST PRESCALER=4;

.CONST TIMFULSCALE=0Xffff;

TEMPMEAS:

si=PRESCALER;

{ For timer prescaler }

sr0=TIMFULSCALE;

{ Timer counter full scale }

dm(0x3FFB)=si;

{ Timer Prescaler set up to 5 }

si=TIMFULSCALE;

{ CLKin=10MHz,Timer Period=32.768ms }

dm(0x3FFC)=si;

{ Timer Counter Register to 65535 }

dm(0x3FFD)=si;

{ Timer Period Register to 65535 }

imask=0x01;

{ Unmask Interrupt timer }

TEST1:

if not fi jump TEST1;

{ Check for FI=1 }

TEST0:

if fi jump TEST0;

{ Check for FI=0 to locate transition }

ena timer;

{ Enable timer, count at a 500ns rate }

COUNT2:

if not fi jump COUNT2;

{ Check for FI=1 to stop count }

dis timer;

ay0=dm(0x3FFC);

{ Save counter=T2 in ALU register }

ar=sr0-ay0;

ax0=ar;

dm(0x3FFC)=si;

{ Reload counter at full scale }

ena timer;

COUNT1:

if fi jump COUNT1;

{ Check for FI=0 to stop count }

dis timer;

ay0=dm(0x3FFC);

{ Save counter=T1 in ALU register }

ar=sr0-ay0;

my0=400;

mr=ar*my0(uu);

{ mr=400*T1 }

ay0=mr0;

{ af=MSW of dividend, ay0=LSW }

ar=mr1; af=pass ar;

{ ax0=16-bit divisor }

COMPUTE:

astat=0;

{ To clear AQ flag }

divq ax0; divq ax0;

{ Division 400*T1/T2 }

divq ax0; divq ax0;

{ with 0.3 < T1/T2 < 0.7 }

divq ax0; divq ax0;

divq ax0; divq ax0;

divq ax0; divq ax0;

divq ax0; divq ax0;

divq ax0; divq ax0;

divq ax0; divq ax0;

divq ax0; divq ax0;

{ Result in ay0 }

ax0=0x03AC;

{ ax0=235*4 }

ar=ax0-ay0;

{ ar=235-400*T1/T2, result in øC }

rts;

{ format 14.2 }

.ENDMOD;

{ End of the subprogram }