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REV.A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. a Serial Digital Output Thermometers
FEATURES
Modulated Serial Digital Output Proportional to Temperature /H115501.5/H11543C Accuracy (typ) from –25 /H11543C to +100/H11543C Specified –40 /H11543C to +100/H11543C, Operation to 150 /H11543C Power Consumption 6.5 mW Max at 5 V Flexible Open-Collector Output on TMP03 CMOS/TTL-Compatible Output on TMP04 Low Voltage Operation (4.5 V to 7 V)
APPLICATIONS
Environmental Control Systems Computer Thermal Monitoring Thermal Protection Industrial Process Control Power System Monitors TMP03/TMP04 PACKAGE TYPES AVAILABLE TO-92 1 2 3 DOUT V+ GND BOTTOM VIEW (Not to Scale) TMP03/TMP04 SO-8 and RU-8 (TSSOP) TOP VIEW (Not to Scale) NC = NO CONNECT TMP03/ TMP04 DOUT NC NC NC NC GND NC GENERAL DESCRIPTION The TMP03/TMP04 are monolithic temperature detectors that generate a modulated serial digital output that varies in direct proportion to the temperature of the device. An onboard sensor generates a voltage precisely proportional to absolute tempera- ture which is compared to an internal voltage reference and input to a precision digital modulator. The ratiometric encoding format of the serial digital output is independent of the clock drift errors common to most serial modulation techniques such as voltage-to-frequency converters. Overall accuracy is ±1.5°C (typical) from –25°C to +100°C, with excellent transducer lin- earity. The digital output of the TMP04 is CMOS/TTL compatible, and is easily interfaced to the serial inputs of most popular microprocessors. The open-collector output of the TMP03 is capable of sinking 5 mA. The TMP03 is best suited for systems requiring isolated circuits utilizing optocouplers or isolation transformers. The TMP03 and TMP04 are specified for operation at supply voltages from 4.5 V to 7 V. Operating from 5 V, supply current (unloaded) is less than 1.3 mA. The TMP03/TMP04 are rated for operation over the –40 °C to +100°C temperature range in the low cost TO-92, SO-8, and TSSOP-8 surface mount packages. Operation extends to 150°C with reduced accuracy. (continued on page 4) Tel: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 © Analog Devices, Inc., 2002
Parameter Symbol Conditions Min Typ Max Unit ACCURACY Temperature Error –25 °C < TA < +100°C1 1.5 4.0 °C Temperature Linearity 0.5 °C Long-Term Stability 1000 Hours at 125 °C 0.5 °C Nominal Mark-Space Ratio T1/T2 T A = 0°C 58.8 % Nominal T1 Pulsewidth T1 10 ms Power Supply Rejection Ratio PSRR Over Rated Supply 0.7 1.4 °C/V TA = 25°C OUTPUTS Output Low Voltage V OL ISINK = 1.6 mA 0.2 V Output Low Voltage V OL ISINK = 5 mA 2 V 0°C < TA < 100°C Output Low Voltage V OL ISINK = 4 mA 2 V –40°C < TA < 0°C Digital Output Capacitance C OUT (Note 2) 15 pF Fall Time t HL See Test Load 150 ns Device Turn-On Time 20 ms POWER SUPPLY Supply Range V+ 4.5 7 V Supply Current I SY Unloaded 0.9 1.3 mA NOTES 1Maximum deviation from output transfer function over specified temperature range. 2Guaranteed but not tested. Specifications subject to change without notice. Test Load 10 kΩ to 5 V Supply, 100 pF to Ground TMP04F Parameter Symbol Conditions Min Typ Max Unit ACCURACY Temperature Error T A = 25°C 1.0 3.0 °C Temperature Linearity 0.5 °C Long-Term Stability 1000 Hours at 125 °C 0.5 °C Nominal Mark-Space Ratio T1/T2 T A = 0°C 58.8 % Nominal T1 Pulsewidth T1 10 ms Power Supply Rejection Ratio PSRR Over Rated Supply 0.7 1.2 °C/V TA = 25°C OUTPUTS Output High Voltage V OH IOH = 800 µA V+ –0.4 V Output Low Voltage V OL IOL = 800 µA 0.4 V Digital Output Capacitance C OUT (Note 2) 15 pF Fall Time t HL See Test Load 200 ns Rise Time t LH See Test Load 160 ns Device Turn-On Time 20 ms POWER SUPPLY Supply Range V+ 4.5 7 V Supply Current I SY Unloaded 0.9 1.3 mA NOTES 1Maximum deviation from output transfer function over specified temperature range. 2Guaranteed but not tested. Specifications subject to change without notice. Test Load 100 pF to Ground REV. A TMP03/TMP04–SPECIFICATIONS TMP03F(V+ = 5 V, –40 /H11543C ≤ TA ≤ 100/H11543C, unless otherwise noted.) –2– (V+ = 5 V, –40 /H11543C ≤ TA ≤ 100/H11543C, unless otherwise noted.)
REV. A –3– WARNING! ESD SENSITIVE DEVICE CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the TMP03 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. ABSOLUTE MAXIMUM RATINGS * Maximum Open-Collector Output Voltage (TMP03) . . . 18 V *CAUTION 1Stresses above those listed under Absolute Maximum Ratings may cause perma- nent damage to the device. This is a stress rating only; functional operation at or above this specification is not implied. Exposure to the above maximum rating conditions for extended periods may affect device reliability. 2Digital inputs and outputs are protected, however, permanent damage may occur on unprotected units from high-energy electrostatic fields. Keep units in conduc- tive foam or packaging at all times until ready to use. Use proper antistatic handling procedures. 3Remove power before inserting or removing units from their sockets. Package Type /H9258JA /H9258JC Units TO-92 (T9) 162 1 120 °C/W SO-8 (S) 158 1 43 °C/W TSSOP (RU) 240 1 43 °C/W NOTE 1ΘJA is specified for device in socket (worst case conditions). ORDERING GUIDE Accuracy Temperature Model at 25 /H11543C Range Package TMP03FT9 ± 3.0 XIND TO-92 TMP03FS ± 3.0 XIND SO-8 TMP03FRU ± 3.0 XIND TSSOP-8 TMP04FT9 ± 3.0 XIND TO-92 TMP04FS ± 3.0 XIND SO-8
REV. A –5– Table I. Counter Size and Clock Frequency Effects on Quantization Error Maximum Maximum Maximum Quantization Quantization Count Available Temp Required Frequency Error (25 /H11543C) Error (77 /H11543F) 4096 125 °C 94 kHz 0.284 °C 0.512 °F 8192 125 °C 188 kHz 0.142 °C 0.256 °F 16384 125 °C 376 kHz 0.071 °C 0.128 °F Optimizing Counter Characteristics Counter resolution, clock rate, and the resultant temperature decode error that occurs using a counter scheme may be deter- mined from the following calculations: 1. T1 is nominally 10 ms, and compared to T2 is relatively insensitive to temperature changes. A useful worst-case assumption is that T1 will never exceed 12 ms over the specified temperature range. T1 max = 12 ms Substituting this value for T1 in the formula, temperature (°C) = 235 – ([T1/T2] × 400), yields a maximum value of T2 of 44 ms at 125 °C. Rearranging the formula allows the maximum value of T2 to be calculated at any maximum operating temperature: T2 (Temp) = (T1max × 400)/(235 – Temp) in seconds 2. We now need to calculate the maximum clock frequency we can apply to the gated counter so it will not overflow during T2 time measurement. The maximum frequency is calculated using: Frequency (max) = Counter Size/ (T2 at maximum temperature) Substituting in the equation using a 12-bit counter gives, Fmax = 4096/44 ms /H11229 94 kHz. 3. Now we can calculate the temperature resolution, or quanti- zation error, provided by the counter at the chosen clock frequency and temperature of interest. Again, using a 12-bit counter being clocked at 90 kHz (to allow for ~5% tempera- ture over-range), the temperature resolution at 25 °C is calculated from: Quantization Error ( °C) = 400 × ([Count1/Count2] – [Count1 – 1]/[Count2 + 1]) Quantization Error (°F) = 720 × ([Count1/Count2] – [Count1 – 1]/[Count2 + 1]) where, Count1 = T1max × Frequency, and Count2 = T2 (Temp) × Frequency. At 25°C this gives a resolution of better than 0.3°C. Note that the temperature resolution calculated from these equations improves as temperature increases. Higher temperature resolution will be obtained by employing larger counters as shown in Table I. The internal quantization error of the TMP03 sets a theoretical minimum resolution of approximately 0.1 °C at 25°C. Self-Heating Effects The temperature measurement accuracy of the TMP03 may be degraded in some applications due to self-heating. Errors intro- duced are from the quiescent dissipation, and power dissipated by the digital output. The magnitude of these temperature er- rors is dependent on the thermal conductivity of the TMP03 package, the mounting technique, and effects of airflow. Static dissipation in the TMP03 is typically 4.5 mW operating at 5 V with no load. In the TO-92 package mounted in free air, this accounts for a temperature increase due to self-heating of ∆T = PDISS × θJA = 4.5 mW × 162°C/W = 0.73°C (1.3°F) For a free-standing surface-mount TSSOP package, the tem- perature increase due to self-heating would be ∆T = PDISS × θJA = 4.5 mW × 240°C/W = 1.08°C (1.9°F) In addition, power is dissipated by the digital output which is capable of sinking 800 µA continuous (TMP04). Under full load, the output may dissipate PDISS = 0.6 V() 0.8 mA() T 2 T1+ T 2 For example, with T2 = 20 ms and T1 = 10 ms, the power dissipation due to the digital output is approximately 0.32 mW with a 0.8 mA load. In a free-standing TSSOP package, this accounts for a temperature increase due to output self-heating of ∆T = PDISS × ΘJA = 0.32 mW × 240°C/W = 0.08°C (0.14°F) This temperature increase adds directly to that from the quies- cent dissipation and affects the accuracy of the TMP03 relative to the true ambient temperature. Alternatively, when the same package has been bonded to a large plate or other thermal mass (effectively a large heatsink) to measure its temperature, the total self-heating error would be reduced to approximately ∆T = PDISS × ΘJC = (4.5 mW + 0.32 mW) × 43°C/W = 0.21°C (0.37°F) Calibration The TMP03 and TMP04 are laser-trimmed for accuracy and linearity during manufacture and, in most cases, no further adjustments are required. However, some improvement in per- formance can be gained by additional system calibration. To perform a single-point calibration at room temperature, measure the TMP03 output, record the actual measurement tempera- ture, and modify the offset constant (normally 235; see the Output Encoding section) as follows: Offset Constant = 235 + (T OBSERVED – TTMP03OUTPUT) A more complicated 2-point calibration is also possible. This involves measuring the TMP03 output at two temperatures, Temp1 and Temp2, and modifying the slope constant (normally 400) as follows: Slope Constant = Temp2 − Temp1 T1@ Temp1 T 2@ Temp1 − T1@ Temp2 T 2@ Temp2 where T1 and T2 are the output high and output low times, respectively.
TEMPERA TURE – /H11543C 0–75 OUTPUT FREQUENCY – Hz V+ = 5V RLOAD = 10k/H9024 –25 25 75 125 175 TPC 1. Output Frequency vs. Temperature TEMPERA TURE – /H11543C 0–75 TIME – ms VS = 5V RLOAD = 10k/H9024 –25 25 75 125 175 TPC 2. T1 and T2 Times vs. Temperature TIME SCALE = 250ns/DIV VOL T AGE SCALE = 2V/DIV SAMPLE ( T ) TA = 25 C VDD = 5V CLOAD = 100pF RLOAD = 1k/H9024 RUNNING: 200MS/s ET CH 1 +WIDTH s Wfm DOES NOT CROSS REF CH 1 –WIDTH s Wfm DOES NOT CROSS REF CH 1 RISE s NO VALID EDGE CH 1 FALL 209.6ns TPC 3. TMP03 Output Fall Time at 25°C SUPPL Y VOL T AGE – V olts 0.97 4.5 NORMALIZED OUTPUT FREQUENCY TA = 25/H11543C RLOAD = 10k/H9024 5 5.5 6 6.5 7 7.5 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.05 TPC 4. Normalized Output Frequency vs. Supply Voltage TIME SCALE = 1/H9262s/DIV VOL T AGE SCALE = 2V/DIV SAMPLE ( T ) TA = 25 C VDD = 5V CLOAD = 100pF RLOAD = 1k/H9024 RUNNING: 50.0MS/s CH 1 +WIDTH s Wfm DOES NOT CROSS REF CH 1 –WIDTH s Wfm DOES NOT CROSS REF CH 1 RISE 500ns CH 1 FALL s NO VALID EDGE TPC 5. TMP03 Output Rise Time at 25°C TIME SCALE = 1/H9262s/DIV VOL T AGE SCALE = 2V/DIV SAMPLE ( T ) TA = 125 C VDD = 5V CLOAD = 100pF RLOAD = 1k/H9024 RUNNING: 50.0MS/s CH 1 +WIDTH s Wfm DOES NOT CROSS REF CH 1 –WIDTH s Wfm DOES NOT CROSS REF CH 1 RISE 5380ns CH 1 FALL s NO VALID EDGE TPC 6. TMP03 Output Rise Time at 125°C REV. A–6– TMP03/TMP04–Typical Performance Characteristics
REV. A –7– CH 1 FALL 139.5ns CH 1 RISE s NO VALID EDGE CH 1 –WIDTH s Wfm DOES NOT CROSS REF CH 1 +WIDTH s Wfm DOES NOT CROSS REF TIME SCALE = 250ns/DIV VOL T AGE SCALE = 2V/DIV SAMPLE ( T ) TA = 125 C VDD = 5V CLOAD = 100pF RLOAD = 1k/H9024 RUNNING: 200MS/s ET EDGE SLOPE TPC 7. TMP03 Output Fall Time at 125°C TIME SCALE = 250ns/DIV VOL T AGE SCALE = 2V/DIV SAMPLE ( T ) TA = 25 C VDD = 5V CLOAD = 100pF RLOAD = 0 RUNNING: 200MS/s ET CH 1 +WIDTH s Wfm DOES NOT CROSS REF CH 1 –WIDTH s Wfm DOES NOT CROSS REF CH 1 RISE s NO VALID EDGE CH 1 FALL 127.6ns TPC 8. TMP04 Output Fall Time at 25°C TIME SCALE = 250ns/DIV VOL T AGE SCALE = 2V/DIV SAMPLE ( T ) TA = 125 C VDD = 5V CLOAD = 100pF RLOAD = 0 RUNNING: 200MS/s ET CH 1 +WIDTH s Wfm DOES NOT CROSS REF CH 1 –WIDTH s Wfm DOES NOT CROSS REF CH 1 RISE s NO VALID EDGE CH 1 FALL 188.0ns TPC 9. TMP04 Output Fall Time at 125°C TIME SCALE = 250ns/DIV VOL T AGE SCALE = 2V/DIV SAMPLE ( T ) TA = 25 C VDD = 5V CLOAD = 100pF RLOAD = 0 RUNNING: 200MS/s ET CH 1 +WIDTH s Wfm DOES NOT CROSS REF CH 1 –WIDTH s Wfm DOES NOT CROSS REF CH 1 RISE 110.6ns CH 1 FALL s NO VALID EDGE TPC 10. TMP04 Output Rise Time at 25°C TIME SCALE = 250ns/DIV VOL T AGE SCALE = 2V/DIV SAMPLE ( T ) TA = 125 C VDD = 5V CLOAD = 100pF RLOAD = 0 RUNNING: 200MS/s ET CH 1 +WIDTH s Wfm DOES NOT CROSS REF CH 1 –WIDTH s Wfm DOES NOT CROSS REF CH 1 RISE 149.6ns CH 1 FALL s NO VALID EDGE TPC 11. TMP04 Output Rise Time at 125°C LOAD CAP ACIT ANCE – pF TIME – ns TA = 25/H11543C VS = 5V RLOAD = 500 1000 1500 2000 2500 3000 500 1000 1500 2000 2500 3500 4000 4500 5000 FALL TIME RISE TIME TPC 12. TMP04 Output Rise and Fall Times vs. Capacitive Load
REV. A–8– TEMPERA TURE – /H11543C –5–50 OUTPUT ACCURACY – /H11543C –25 0 25 50 75 100 125 V+ = 5V RLOAD = 10k/H9024 TMP03 TMP04 MAXIMUM LIMIT MINIMUM LIMIT MEASUREMENTS IN STIRRED OIL BA TH TPC 13. Output Accuracy vs. Temperature TIME – ms V+ = 5V RLOAD = 10k/H9024 10 20 30 40 50 –55 15 10 25 20 10 125 35 10 TYPICAL VALUES TEMP T2 T1 /H11543C ms ms T1 T2 0, T1 T1T2 OUTPUT ST ARTS LOW OUTPUT ST ARTS HIGH 60 70 80 90 100 0, T2 TPC 14. Start-Up Response TEMPERA TURE – /H11543C 750–75 SUPPL Y CURRENT – /H9262A V+ = 5V NO LOAD –25 25 75 125 175 800 850 900 950 1000 1050 1100 TMP03 TMP04 TPC 15. Supply Current vs. Temperature TEMPERA TURE – /H11543C –75 ST ART -UP SUPPL Y VOL T AGE – V olts –25 25 75 125 175 3.5 4.5 RLOAD = 10k/H9024 ST ART -UP VOL T AGE DEFINED AS OUTPUT READING BEING WITHIN /H115505/H11543C OF OUTPUT A T 4.5V SUPPL Y TPC 16. Start-Up Voltage vs. Temperature SUPPL Y VOL T AGE – V olts SUPPL Y CURRENT – /H9262A TA = 25/H11543C NO LOAD 1 2 3 4 5 200 400 600 800 1000 1200 1400 678 1600 TPC 17. Supply Current vs. Supply Voltage TEMPERA TURE – /H11543C 0–75 POWER SUPPL Y REJECTION – /H11543C/V –25 25 75 125 175 0.5 1.5 V+ = 4.5V TO 7V RLOAD = 10k/H9024 2.5 3.5 TPC 18. Power Supply Rejection vs. Temperature
REV. A –9– DEVIA TION IN TEMPERA TURE – /H11543C FREQUENCY – Hz 1 10 –0.5 0.5 100 1k 100k 1M 10M10k NORMAL PSSR V+ = 5V DC /H1155050mV AC RLOAD = 10k/H9024 TPC 19. Power Supply Rejection vs. Frequency TEMPERA TURE – /H11543C 0–75 OPEN-COLLECTOR OUTPUT VOL T AGE – mV –25 25 75 125 175 100 150 200 V+ = 5V 250 350 300 400 ILOAD = 5mA ILOAD = 1mA ILOAD = 0.5mA TPC 20. TMP03 Open-Collector Output Voltage vs. Temperature AIR VELOCITY – FPM /H9270 TIME CONST ANT – sec 100 200 300 400 500 V+ = 5V RLOAD = 10k/H9024100 140 120 TRANSITION FROM 100/H11543C OIL BA TH TO FORCED 25/H11543C AIR SOIC - NO SOCKET 600 700 TO –92 - WITH SOCKET TO –92 - NO SOCKET TPC 21. Thermal Time Constant in Forced Air TEMPERA TURE – /H11543C 2–75 SINK CURRENT – mA –25 25 75 125 150 VOL = 1V V+ = 5V TPC 22. TMP03 Open-Collector Sink Current vs. Temperature TIME – sec 250 OUTPUT TEMPERA TURE – /H11543C 25 50 75 100 125 VS = 5V RLOAD = 10k/H9024 105
100 TRANSITION FROM 100/H11543C STIRRED
OIL BA TH TO STILL 25/H11543C AIR 150 175 SOIC TO –92 /H9270 ~ 23 SEC (SOIC, NO SOCKET) /H9270 ~ 40 SEC (TO –92, NO SOCKET) 200 225 250 275 300 TPC 23. Thermal Response Time in Still Air TIME – sec 250 OUTPUT TEMPERA TURE – /H11543C 10 20 30 40 50 V+ = 5V RLOAD = 10k/H9024 100 TRANSITION FROM STILL 25/H11543C AIR TO STIRRED 100/H11543C OIL BA TH SOIC TO –92 /H9270 1.25 SEC (SOIC IN SOCKET) /H9270 2 SEC (TO –92 IN SOCKET) TPC 24. Thermal Response Time in Stirred Oil Bath
REV. A–12– Listing 1. An 80C51 Software Routine for the TMP04 ; Test of a TMP04 interface to the 8051, ; using timer 0 and timer 1 to measure the duty cycle ; This program has three steps: ; 1. Clear the timer registers, then wait for a low-to- ; high transition on input P1.0 (which is connected ; to the output of the TMP04). ; 2. When P1.0 goes high, timer 0 starts. The program ; then loops, testing P1.0. ; 3. When P1.0 goes low, timer 0 stops & timer 1 starts. The ; program loops until P1.0 goes low, when timer 1 stops ; and the TMP04’s T1 and T2 values are stored in Special ; Function registers 8AH through 8DH (TL0 through TH1). ; Primary controls $MOD51 $TITLE(TMP04 Interface, Using T0 and T1) $PAGEWIDTH(80) $DEBUG $OBJECT ; Variable declarations PORT1 DATA 90H ;SFR register for port 1 ;TCON DATA 88H ;timer control ;TMOD DATA 89H ;timer mode ;TH0 DATA 8CH ;timer 0 hi byte ;TH1 DATA 8DH ;timer 1 hi byte ;TL0 DATA 8AH ;timer 0 lo byte ;TL1 DATA 8BH ;timer 1 low byte ORG 100H ;arbitrary start READ_TMP04: MOV A,#00 ;clear the MOV TH0,A ; counters MOV TH1,A ; first MOV TL0,A ; MOV TL1,A ; WAIT_LO: JB PORT1.0,WAIT_LO ;wait for TMP04 output to go low MOV A,#11H ;get ready to start timer0 MOV TMOD,A WAIT_HI: JNB PORT1.0,WAIT_HI ;wait for output to go high ;Timer 0 runs while TMP04 output is high SETB TCON.4 ;start timer 0 WAITTIMER0: JB PORT1.0,WAITTIMER0 CLR TCON.4 ;shut off timer 0 ;Timer 1 runs while TMP04 output is low SETB TCON.6 ;start timer 1 WAITTIMER1: JNB PORT1.0,WAITTIMER1 CLR TCON.6 ;stop timer 1 MOV A,#0H ;get ready to disable timers MOV TMOD,A RET END Software for the interface is shown in Listing 1. The program monitors the TMP04 output, and turns the counters on and off to measure the duty cycle. The time that the output is high is mea- sured by Timer 0, and the time that the output is low is measured by Timer 1. When the routine finishes, the results are available in Special Function Registers (SFRs) 08AH through 08DH.
continues to run while the program monitors the input port. the TMP04’s temperature can be calculated in software. error caused by the 2 µs delay is only about ±0.15°C. pin is required for the interface (Figure 11). Figure 11. Interfacing the TMP04 to the ADSP-210x Digital The timer of the ADSP2101 is implemented as a down counter.
10 MHz crystal oscillator by 5 and thereby decrement the counter
so the exact clock frequency is not important. counter is reloaded and runs until the TMP04 output goes low. using the scale factor of Equation 1.
- The circuit measures the output pulsewidths with a resolu-
have a maximum period of 65 ms. count the next TMP04 output phase. polarity, were read before the next phase reversal of the TMP04.
REV. A–14– { 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 } Listing 2. Software Routine for the TMP04-to-ADSP-210x Interface
measure the temperature of the air flowing over the board.
10 GND
Figure 12. A Hardware Interface for the TMP04 dissipation microprocessor or other IC is shown in Figure 13.
Dimensions shown in inches and (mm). Figure 13. Monitoring the Temperature of a High Power ticular application, and the equivalent power of the heat source.