Addition to the user manual for the AVR Transistor tester
Contents
1. Capacitor Result of Result of Result of Result of Result of Multimeter Mega8 1MHz Mega8 8MHz Mega88 1MHz Mega88 8MHz PeakTech signature 1E 9307 signature 1E 9307 signature 1E930A signature 1E 93 0A 3315 Original software WITH _AUTO_REF S6pF 58pF 58pF 0 42pF with 28 58pF 0 a Diode 110pF 114pF 114pF 0 111pF 3 117pF 3 220pF 225pF 0 27nF 20 226pF 0 222pF 0 228pF 0 1000pF 1034pF 1 18nF 14 988pF 4 966pF 7 981pF 5 3 3nF 3 47nF 3 90nF 12 3287pF 5 3223pF 1 3230pF 1 7500pF 7 23nF 8 43nF 16 7241pF 0 7079pF 3 7092pF 2 10nF 10 45nF 11 93nF 14 10 13nF 3 9935pF 5 9922pF 5 33nF 33 2nF 37 27nF 12 31 97nF 4 31 26nF 6 31 36nF 6 100nF 97nF 112 36nF 16 97 02nF 9 94 98nF 3 94 93nF 3 330nF 333nF 385 41nF 14 333 2nF 0 325 9nF 2 325 7nF 2 luF 955nF 1 10uF 15 954nF 0 934nF 2 934nF 2 2 2uF 2 2uF 2 54uF 15 2198nF 0 2150nF 2 2149nF 2 22uF 21 94uF 25 61uF 16 21 92uF 0 21 41uF 3 21 4luF 3 47uF 47 5 uF 55 29uF 16 47 30uF 0 46 70uF 1 46 9uF 1 100uF 97 5uF 112 94uF 15 91 30uF 6 91 7uF 6 91 3uF 6 220uF 229uF 272 69uF 19 219 2uF 5 219 2uF 5 219 2uF 5 1000uF 1071F 1371 95uF 28 1076uF 0 1063uF 1 1066uF 1 2200uF 2 231mF 3308 58uF 48 2302uF 3 2288uF 3 2309uF 3 4702. 2 is shown Meaning of this is as follows The L is the symbol for Low meaning the 6809 resistors The 1 stand for resistor at pin 1 is connected to VCC The following 2 means A GND connected resistor at pin 2 The result of this measurement is displayed in row 2 at the first place In row 1 follows now a 3 which means that the first connection of measurement 1 continues but that the GND connected resistor at pin 3 is now in action The result is displayed in the middle place of row 2 The last measurement of this test 2 means that now the resistor at pin 2 is connected to VCC and the GND connection of measurement 2 continues The result of measurement is displayed at the last place of LCR row 2 Please remember that the resolution of the ADC is about 4 88mV All these combinations with respect to the internal resistance of the pins should result to 5001 18 680 680 22 18 680 2493 3 Comparing of the 470kQ resistors Now the display shows in row 1 H1 2 3 2 The same procedure as done in step 2 is repeated with the 470kQ resistors symbol H Result should be nearly 5001 18 470000 470000 22 18 470000 2500 for all combinations 4 In this step nothing is measured but the order is displayed isolate Probe which means that it is time to separate the probes release from wire 5 This step tests the capability of GND connected 470kQ resistors H t
3. are not detected in all cases Does program work correctly without the automatic shut off 15 Appendix T to do list not sorted Software Version 0 93k Add more and better documentation By my tests I have noticed that the measured voltages of the internal Band cap reference is lower than the data sheets let me expect The reason is unknown VCC ADC error Check if transistor tester could get better interpolated ADC values if additional noise is added to the signal or to the ADC reference see ATMEL document AVR121 Enhancing ADC resolution by oversampling If all items are identical there can t be any enhancement of resolution by oversampling Can enough noise be generated with the ATmega counter How additional noised affects the upper and lower limit values Of course this method can not eliminate all of the ADC errors Test of the effectivity of this method can be done by building a ramp input signal and monitoring this signal The ramp signal can be build by slowly charging a big capacitor with the 470kQ resistor The growing of the voltage can then be monitored with the LCD display in a special part of self test The difference of the ReadADC function alternatives 44 9 22 2 9 or 11 4 9 can be monitored too Think about how we can get the real internal resistance of port B output resistor swiching port instead of assuming that ports are equal Can discharging of capacitors be made more quickly if the minus pin is addit
4. 3409 0 1 3392 0 3 3392 0 3 3409 0 3402 0 680Q 0 1 6782 0 3 6782 0 3 6812 0 1 679Q 0 1 13609 0 1 1359Q 0 1 1358Q 0 1 1359Q 0 1 1359Q 0 1 3 90kQ 0 1 3894Q 0 2 38959 0 1 3909Q 0 2 39039 0 1 7 80kQ 0 1 7813Q 0 2 7782Q 0 2 7828Q 0 4 78080 0 1 11 0KQ 0 1 11 04kQ 0 4 10 96kQ 0 4 11 08kQ 0 7 11 02kQ 0 2 22 0kQ 0 1 21 30kQ 3 2 21 60KQ 1 8 21 30kQ 3 2 21 7kQ 1 4 44 0kQ 0 1 43 10kQ 2 0 43 40kQ 14 43 30kQ 1 6 43 6kQ 0 9 50kQ 0 1 49 20kQ 1 6 49 30kQ 14 49 30kKQ 1 4 49 60kQ 0 8 100kQ 0 1 98 90kQ 1 0 9910kQ 9 9 99 10kQ 0 9 99 50kQ 0 5 200kQ 0 1 198 1kQ 1 0 198 1kQ 1 0 198 4kQ 0 8 198 4kQ 0 8 270kQ 0 1 267 7kQ 0 8 267 9kQ 0 8 267 9KQ 0 8 267 9kQ 0 8 470kQ 0 1 468 0kQ 0 4 468 0kQ 0 4 468 4kQ 0 3 468 6kQ 0 3 940kQ 0 1 938 6kQ 0 2 938 7kQ 0 2 940 8kQ 0 1 940 8KQ 0 1 1 00MQ 0 1 995 8kQ 0 4 995 3kQ 0 5 997 1kQ 0 3 998 0kQ 0 2 2 00MQ 0 1 1989kQ 0 6 1990kQ 0 5 1998kKQ 0 1 1990kQ 0 5 10OMQ 1 9894kQ 1 1 9857kQ 14 10 10MQ 1 0 9940kQ 0 6 additional 48MQ 4 47MQ 6 53 40MQ 7 48 3MQ 4 50MQ 1 51MQ 50MQ not detected 50 2MQ The resistor measurement of many multimeter s ends at 20MQ or 40MQ 10 Appendix Cl results of capacity measurements Software Version 0 92k old
5. Pin 3 The measurement with the other polarity are omitted Unfortunately the measurement of capacities had not the expected accuracy with respect to different AVR s what I know from a single user s response As a reason I assumed the difference of the internal 1 3V reference voltage which was used with the comparator Therefore the actual release can use a table with the theoretical dependency of the load time in respect to the comparator voltage The table is spaced in 50mV steps and will be 2 10 11 interpolated according to the actual reference voltage This function uses some of the limited flash memory I hope that the reason for the different measurement values is found Now the reference voltage is read by every power on if this function is selected with the option WITH_AUTO REF I noticed that the reference voltage is permanently somewhat to low so that you can choose an offset with the Makefile option REF_KORR The measured reference voltage will then be corrected added by your value mV units Discharging of capacitors is changed If the voltage is below 1300mV the capacitor is shortened by the output pins of the connected ADC port Port C I believe that this is legal because every output port has a built in resistance of about 20Q The data sheet Figure 149 page 258 shows curves up to 2V Of course I can not guaranty that no damage can occur I have tested the function with a 15mF Capacitor many times and I have never n
6. the first row where x y and z can be any of the pin numbers 1 3 The second row shows the value of the resistor which is connected to pin x and pin y followed by the value of the resistor connected to pin y and pin z If you don t want to compute the total value yourself disconnect pin y and start measurement again If the potentiometer is adjusted to one of its ends the Transistor tester cannot differ the middle pin and the end pin Capacitors are displayed with its symbol in the format Pin number symbol Pin number The measurements of capacitor values are done by measurement of load time The original software did this with a program loop which reads the corresponding digital input pin until switch occurred and count the loop cycles This has the handicap that the resolution is limited by the total time consumption of one loop cycle I have replaced this loop for little capacitor values about lt 50uF by a technical feature of the AVR that the counter can save its counter value by a external event The counter can operate at full clock rate 1MHz or 8MHz The external event can be build by the output of the comparator The comparator can operate with any ADC input pin and Band cap reference So I discharge the capacitor prepare the comparator to the proper pin input start the counter at 0 and start charging of the capacitor with the 470kQ resistor Now I check in a program loop if the counter flags signals a overflow event
7. 0uF 4 75mF 6103 00uF 28 5042uF 6 5042uF 6 4982uF 5 14 1mF 14 4mF 5Q 15 13mF 5 15 13mF 5 15 31mF 6 11 Appendix C2 Results of capacity measurements Software Version 0 94k Capacitor Result of Result of Result of Result of Result of Multimeter Mega8 amp 8MHz Mega8 8MHz Megal68 8 MHz Megal68 amp MHz PeakTech331 Signature 1E 93 07 Signature 1E 93 07 Signature 1E 94 06 Signature 1E 94 06 5 WITH_AUTO_REF WITH_AUTO_REF WITH_AUTO_REF AUTOSCALE_ADC AUTOSCALE_ADC REF_KORR 17 56pF 58pF 58pF 0 57pF 2 57pF 2 58pF 0 110pF 114pF 114pF 0 114pF 0 113pF 1 118pF 4 220pF 225pF 225pF 9 225pF 0 223pF 1 232pF 3 1000pF 1034pF 987pF 5 987pF 5 968pF 6 1007pF 3 3 3nF 3 35nF 3294pF 2 3287pF 2 3214pF 4 3324pF 1 7500pF 7 23nF 7241pF 0 7240pF 0 7038pF 3 7310pF 1 10nF 10 45nF 10 06nF 4 10 10nF 3 9841pF 6 10 20nF 2 33nF 33 2nF 32 50nF 2 32 50nF 2 30 46nF 8 32 69nF 2 100nF 97nF 97 06nF 9 96 87nF 9 94 26nF 3 97 71nF 1 330nF 333nF 332 4nF 0 332 0nF 0 322 8nF 3 334 8nF 1 luF 955nF 953 6nF 0 952 4nF 0 925 8nF 4 960 3nF 1 2 2uF 2 2uF 2195nF 0 2195nF 0 2134nF 3 2214nF 1 22uF 21 94uF 21 87uF 0 21 92uF 0 21 26uF 3 22 07uF 1 47uF 47 5uF 47 40uF 0 47 49uF 0 47 27uF 1 47 31 UF 1
8. 1 625mV BC546B NPN B 381 780mV NPN B 376 777mV NPN B 387 771mV BC556B PNP B 266 790mV PNP B 429 787mV PNP B 266 790mV BC639 NPN B 180 722mV NPN B 180 733mV NPN B 188 724mV BC640 PNP B 185 716mV PNP B 227 725mV PNP B 187 719mV AC128 Ge PNP B 68 270mV PNP B 64 269mV PNP B 66 271mV BCS517 NPN B 26996 1419mV NPN B 28220 1413mV NPN B 28250 1404mV BCS516 PNP B 65535 1430mV PNP B 65535 1420mV PNP B 65535 1417mV BS170 N E MOS D 2616mV 66pF N E MOS D 2562mV 67pF N E MOS D 2564mV 68pF J310 N JFET N JFET N JFET BRY 55 200 Thyristor Thyristor Thyristor IRFU120N N E MOS D 4151mV 922pF N E MOS D 4156mV 894pF N E MOS D 4153mV 933pF IRFU9024 P E MOS D 3525mV 960pF P E MOS D 3525mV 926pF P E MOS D 3534mV 965pF ZVP2106A P E MOS D 3217mV 115pF P E MOS D 3220mV 114pF P E MOS D 3217mV 113pF ZVNL120A N E MOS D 1560mV 140pF N E MOS D 1535mV 138pF N E MOS D 1535mV 138pF 13 Appendix E Pictures Test version with unmounted 4x20 Display VF i V ae N Cecek Ery ee w pis if Modifications 8MHz Crystal Pin9 10 and Pull up resistor Pin12 13 better Pin13 and VCC 14 Appendix F Known errors Software Version 0 94k The measurement results of little capacity values vary with the Pin combinations Combination 1 2 values are about 3pF less than the values of the other pin combinations 1 3 and 2 3 This effect is equal on any tested AVR processor Germanium Diodes AC128
9. 100uF 97 5uF 91 68uF 6 91 54uF 6 90 72uF 7 91 68uF 6 220uF 229uF 218 8uF 4 220 9uF 4 218 8uF 4 216 6uF 5 1000uF 1071pF 1076uF 1 1076F 0 1069uF 0 1062uF 1 2200uF 2 231mF 2289uF 3 228luF 2 2289uF 3 2246uF 1 4700uF 4 75mF 5032uF 6 4999uF 5 5032uF 6 4923uF 4 14 1mF 14 4mF 15 34mF 6 15 29mF 6 15 17uF 5 14 99mF 4 12 Appendix D Results of semiconductor tests Software Version 094k semiconductor Result of Result of Result of Mega8 8MHz Megal68 8MHz Megal68 8MHz signature 1E 93 07 signature 1E 93 07 signature 1E 94 06 WITH_AUTO_REF WITH_AUTO_REF AUTOSCALE ADC 1N4148 Diode 721mV OpF Diode 729mV OpF Diode 725mV OpF 1N4150 Diode 678mV OpF Diode 681mV OpF Diode 682mV OpF BA157 Diode 623mV 17pF Diode 631mV 16pF Diode 620mV 15pF BY398 Diode 541mV OpF Diode 553mV OpF Diode 542mV OpF 1N4007 Diode 654mV 13pF Diode 665mV 9pF Diode 658mV 11pF LED green Diode 1954mV 6pF Diode 1970mV 6pF Diode 1951mV 4pF ZPD2 7 2xDi 729mV 2659mV 2xDi 738mV 2674mV 2xDi 730mV 2656mV BUS508A NPN B 9 613mV NPN B 9 621mV NPN B 9 615mV BUS508A B E Diode 613mV 5201pF Diode 621mV 5285pF Diode 611mV 5344pF BUS508A B C Diode 595mV 261pF Diode 597mV 267pF Diode 591mV 272pF 2N3055 NPN B 21 617mV NPN B 21 626mV NPN B 2
10. 3 602 0 1202 0 1 120Q 0 1220 1 6 1200 0 240Q 0 1 2402 0 2402 0 2390 0 4 340Q 0 1 3392 0 3 3392 0 3 3402 0 680Q 0 1 6772 0 4 6772 0 4 6792 0 1 1360Q 0 1 1357kQ 0 2 13520 0 6 13612 0 1 3 90kQ 0 1 38652 0 9 3859Q 1 1 38962 0 1 7 80kQ 0 1 7676Q 1 6 7652Q 1 9 7776Q 0 3 11 0kQ 0 1 109020 0 9 10 70kQ 2 7 10 91kQ 0 8 22 0kQ 0 1 21 1kQ 4 1 21 1kQ 4 1 21 1kQ 4 1 44 0kQ 0 1 43 1kQ 2 0 43 0kQ 2 3 43 0kQ 2 3 50kQ 0 1 49 2kQ 1 6 49 2kQ 1 6 49 2kQ 1 6 100kQ 0 1 99 0kQ 1 0 98 9kQ 1 1 98 9kQ 1 1 200kQ 0 1 196 8kQ 1 6 197 7kQ 1 2 198 6kQ 0 7 270kQ 0 1 266 3kQ 1 4 267 5kQ 0 9 268 6kQ 0 5 470kQ 0 1 77 46uF 467 1kQ 0 6 469 0kQ 0 2 940kQ 0 1 919 6kQ 2 2 935 7kQ 0 5 940 0kQ2 0 1 00MQ2 0 1 973 8kQ 2 6 990 8kQ 0 9 996 2kQ 0 4 2 00MQ2 0 1 1922 0kQ2 3 9 1 975MQ 1 3 1 996MQ 0 2 10MQ 1 8433 8kQ 15 7 9 574MQ 4 10 11MQ 1 additional 43 87MQ 12 52 94MQ 6 50MQ 1 Appendix B2 Results of resistor measurements Software Version 0 94k Resistor Result of Result of Result of Result of Mega8 8MHz Mega8 8MHz Megal68 8MHz Megal68 8MHz Signature 1E 9307 Signature 1E 93 07 Signature 94 06 Signature lE 94 06 AUTOSCALE_ADC AUTOSCALE_ADC 602 0 1 602 0 612 1 7 602 0 602 0 120Q 0 1 1202 0 1202 0 1202 0 120Q 0 240Q 0 1 2409 0 2409 0 2409 0 2399 0 4
11. Addition to the user manual for the AVR Transistor tester K H Kiibbeler is only valid for the test version 0 94k Introduction Based to the Software of Markus Frejek I had started to modify the software At the beginning the reason for this was a problem which I had with the programming of EEprom Because writing to the flash memory was without problems I believed that it is the quickest and best way to get a run capable tester if I put the texts and parameters away from the EEprom and put them in the flash memory instead Beginning from version 0 92k you can select with option USE_EEPROM if EEprom should be used or not By analysing the software I had an additional idea which I have implemented as a test In order to display the voltage values are needed in mV and not in steps of the ADC This was done by original software for every value which is displayed On the other side the original function ReadADC reads the ADC Value twenty times adds every value and divide the sum by twenty The resolution of the result is again 5 000mV 1023 same as ADC If I read the ADC value instead of 20 times now 22 times build the sum and double the sum and divide by nine then my maximum value is 22 2 1023 9 5001 what matches nearly perfect to the wanted mV resolution But with this idea real work started Now all if statements in the program must be adapted to the new resolution So I learned more and more about the software of Markus Frejek My a
12. ctual version of the function ReadADC reads the ADC value 45 times but adds only the last 44 values and divides the result by 9 Because I had the initial ambition to put the software of the reduced version without resistor and capacitor measurement in 4K flash I did modifications which were not really necessary So I replaced the wait loops by calls to a new written assembler routine which uses only 66 bytes of flash every call need only one instruction but serves a total range from 10s to 5s in steps of 123 45 10 The routine includes the Watch Dog Reset for all calls above 100ms Wait calls with interim value such as 8ms need two calls Sms and 3ms I don t know any implementation which is more economical if you use many wait calls in your program The wait calls matched the exactly delay time if the lowest time wait call does Only the 100ms wait time calls are lus longer if your clock is 1MHz because of the additional Watch Dog Reset The calls uses no registers only the Stack Pointers for the return addresses in the RAM at most 28 Byte stack space in current release is used The software version for 8MHz clock needs less memory than the 1MHz version because the LCD functions can then use this calls too In this case the additional calls 1us 2us 3us 4us and Sus are possible New features and modifications Measuring of resistors are upgraded so that potentiometers can be connected The display format for this measurement is x O y O Z in
13. e with common collector emitter follower The hFE value of High Power transistors a more acceptable if measured by this way In this kind of connection there is no risk to overload the base even if the base is supplied with the 680Q resistor In case of Darlington transistor the voltage over the base resistor is too little so this measurement is done also with the 470kQ base resistor release 0 92k The normal measurement with common emitter is also done as before and the higher value of hFE is displayed Because Darlington transistors can have very high hFE values gt 20000 the display layout is changed from hFE to B to save space The differences of reference voltage of ATmega8 ATmega88 ATmegal68 and ATmega328 are applied as noted in the data sheet You can also use the feature WITH_AUTO_REF with a Makefile option in this case the reference Voltage is read out with ADC The factor to transform the measured load time to capacity is dependent of the reference voltage If the curves in the data sheet are not only for one example reading of actual reference voltage should not be required but I m in doubt about it 12 13 14 15 16 The measurement of big capacitor values is expanded to values up to 100mF Because I don t have such big capacitors I could not yet test this Capacity of Gold capacitors could not measured correctly by this method too quickly Use of the AVR with 8MHz crystal is added to the Makefile The cor
14. fuse is selected automatically by Makefile Only for the ATmega8 you must install the 1MHz crystal if you wish to use a MHz clock operation with a crystal Linux user should be able to get an ready transistor tester with 4 steps e Edit the Makefile select your processor type your programmer and options e call make connect the ISP plug and call make upload e if necessary call make fuses or call make fuses crystal and disconnect the ISP plug Beginning from version 0 92k the ReadADC function adds 4 to the sum before dividing by 9 round up to next integer Beginning from version 0 93k you can select the special option AUTOSCALE_ADC for the ReadADC function so that not only the 5V reference is used for measurements additionally the internal reference 1 1V for ATmega168 will be used if the input voltage enables that Input voltage must be lower than 1V Especially if the software switch the reference from 5V to 1 1V the software must wait more than 5ms until the selected reference is stable The reason for this is the external installed 100nF capacitor at the AREF pin 21 of the ATmega Switch back to 5V is much quicker 300us The necessary additional wait time results in a significant greater measurement period for capacitors with big values because very often must be switched between 5V and 1 1V reference The resolution of ReadADC function is always mV 17 18 19 20 21 Version 0 94k ha
15. he benefit measurements around 22kQ In version 0 93k have I added fill characters to the different texts to get the same length for every implemented language In version 0 94k I have removed this fill characters again because I had noticed that there is no space left in EEprom for the additional data required to implement the option LCD_CYRILLIC To make this option selectable again the overrun area of the table RLtab was additionally removed By optimizing the program in version 0 94k it is possible to select the self test function together with all other options without AUTOSCALE ADC for a ATmega8 Therefore the output of capacity value and the output of resistor value now uses a common function The computation of the current amplification factor for bipolar transistors is in version 0 94k done with long int 32 bit but result is limited to 65535 match 16 bit The overrun problem was reason for the implausible results of previous versions BC516 measurements I think that optimising of measurement results is nearly finished Some more response from users would be helpful I hope that I have not forgotten any important item and will introduce a last item for which I will spend a separate chapter Self test Function Beginning with release 0 9k I have implemented a self test function Usage is very simple If you have installed test terminal with clamps put all clamps together to a piece of uninsulated wire and pres
16. ionally raised with the 680Q resistor to VCC Who is using the serial port I did not test this function and even I don t know how Can inductance be tested How measurement results changes by variation of the supply voltage between 4 5V and 5V Find better organisation of directory structure Check if the tester can use floatingpoint representation of values The risk of overflow is lower There is no need to use multiplication and division together to build a multiplication with a non integer factor But I don t know how much flash memory must be spend for the library Write User s guide for configuring the tester with the Makefile options and description of the build chain Development of a new board with crystal or crystal generator clock for ATmega If the holding current of a thyristor can not be reached with the 680Q resistor is it harmless to switch the cathode directly to GND and the anode directly to VCC for a very short time The current could reach more than 100ms Will the port be damaged What is with the power supply voltage regulator Check the Port afterwards with self test function Can voltage regulators be checked Input Output GND Can optoelectronic couplers be checked Can the transistor tester act as clock generator for AVR devices which can t be programed because of wrong fuse configuration Test if 0 1Q can be displayed with the AUTOSCALE_ADC option of ATmega168 In this case probably the ESR measuremen
17. ltage of the 680Q resistor 5001 result of test 7 result of test 8 To get the current build voltage of 680Q resistor 680 Then you can get both resistor values by dividing the voltage result of test 7 or 8 by the current 9 A 50Hz rectangle signal is generated on Pin 2 and the same signal in opposite direction on Pin 3 Pin 1 is switched to GND The current is limited with 680Q resistors This test is repeated 8 times with 5 seconds period each You can check the time of the wait calls if you have an oscilloscope or frequency counter If you don t use the crystal clock version the result may be inexactly A exactly clock frequency and wait time are important for measurement of capacity values At the end of test function the text Auto Test End is shown in row 1 and the version number of software is shown in row 2 Then the program continues with the normal measurement task Beginning from version 0 93k a test step is not further repeated if the start key is pressed If you leave the key pressed every test is executed only once You can configure self test only together with all other options for a ATmegal68 ATmega328 untested For the ATmega8 you must at least omit the option AUTOSCALE_ADC because of the limited flash memory Appendix A Result of self test Software Version 0 94k Microcontroller 1 Result 2 Result 3 Result Mega8 8MHz Tes
18. o pull the test pins to GND Row 1 shows the text RH Row 2 should display zero for all three pins 6 This step tests the capability of VCC connected 470kQ resistors H to pull the test pins to VCC Row 1 shows the text RH The best value for this three measurements is 5001 Great differences from the best value for test 5 and 6 are errors such as isolation problem flux material or damaged port 7 Measuring of internal resistance of pin output switched to the GND signal The text in the 1st LCD row is Ri_Lo mV In the second row of the LCD three voltages were displayed The internal resistance of the port C outputs switched to GND are measured with the current of to VCC switched 680Q resistors Only the three pins of the ADC port are measured the resistor port B PBO PB2 and PB4 can not be measured without hardware modification Is is assumed that the port resistance of the different ports are nearly identical To get the resistor values you must divide the displayed mV values by about 7 see test 8 8 Measuring of internal resistance of port outputs switched to the VCC signal The needed current is generated with to GND connected 680Q resistors The text in the 1st LCD row is Ri_Hi mV In the second row of the LCD three voltages are displayed in difference to VCC It are the same measurements as those in test 7 to the other side With the following steps you can get the resistance To get the vo
19. or a input capture external event I count the overflow events until I detect the input capture event In this case I stop the counter and check if I must count a additional overflow because the counter can t be stopped by the input capture event The input capture counter and the overflow counter built together the total time from which I subtract a experimental find out constant to eliminate the measurement offset I don t know if this constant must be adapted to other boards or processors Capacitors with bigger values as about 50uF are measured in an previous test This is done by up to 500 load pulses with a length of 10ms which is done with the 680Q resistor Load pulses are repeated until the load voltage reached more than 300mV measured without any load current The value of the capacity is then computed from the count of load pulses and the reached load voltage from a table The table contains the factors to get the capacity in nF units from load time and the reached voltage with a spacing of 25mV Interim value of voltage will be interpolated As a result of the lower load voltage the measurement time is much faster because this advantage works also on discharging Furthermore a diode which is parallel connected to the capacitor don t disturb the measurement in most cases because the flux voltage of most diodes is not reached Capacitors are measured only in three combinations Pin 1 and Pin 3 Pin 1 and Pin 2 plus Pin 2 and
20. oticed any problem The current should be below the specified limit of 40mA Damage can occur if you don t discharge a high voltage capacitor before connecting it to your tester The format of displaying diodes is replaced by an diode symbol surrounded with the pin numbers This should be known by every user with any first language Unfortunately I see no way to show different symbols for special diodes like breakdown diode Please notice the pin numbers instead If the outside pin numbers of two diodes are identical it can be a two in one LED a breakdown diode or something else Notice the flux voltages The measurement of single diodes is supplemented by a capacity measurement in inverse direction Probably is is possible to select a diode for different purposes I have measured values between some pF up to 5nF base emitter diode of a BUSO8A Transistor A experimental parallel connection of a diode and a capacitor with 330uF was detected correctly If the capacitor has greater value only the capacitor is detected Of course this measurement can also be done for diodes of bipolar transistors if you connect the base and only one of the other terminals collector or emitter To save program place the format of displaying pin numbers of bipolar transistors is changed to the form EBC xyz Where EBC means Emitter Base and Collector and xyz means the sequence of the corresponding pin numbers The measurement for bipolar transistors is also don
21. rect fuses for the different ATmega s is selected with the make fuses crystal call If you prefer the operation with 1MHz the clock divide by 8 fuse is selected automatically for the ATmega88 line The ATmega8 must be connected with a 1MHz crystal if you wish to use the 1MHz crystal mode no clock divide Beginning from version 0 92k the program can be configured with Makefile options You can select a supported language if you wish to use measurement of resistors or capacities if you want a serial output if the battery voltage is displayed at the beginning if you wish to use the self test function and if the program should use the EEprom Additionally you can select your clock frequency 1MHz or 8MHz You can also select which processor you have installed m8 m48 m88 m168 and m328 and which programmers avrisp2 you have connected if you use avrdude as programmer interface call make upload The avrdude program checks signature before any load of program data is done If the correct processor is not found program terminates with a error message You can select a clock generation with internal RC generator make fuses and a clock generation with a external crystal make fuses crystal You can use the crystal version only if you have installed a 8MHz crystal between pin 9 and pin 10 of your ATmega If you wish to use an 1MHz clock operation with crystal you can do this If you have a ATmega88 ATmegal68 or ATmega328 the clock divide
22. s a new option in the Makefile NO_AREF_CAP which will reduce the wait time between switching the ADC reference between 1 1V and 5V You can use this option only if the 100nF capacitor connected to the AREF pin 21 is removed or replaced with a 1nF capacitor I have not noticed any degradation of measurements if this capacitor is removed This option does have effect only if the AUTOSCALE_ADC option is selected too I have installed a InF capacitor after all Version 0 93k changes the measurement of resistors The measurement of voltage of the directly switched pin ADC port is removed only the Pin which is connected across a resistor to the power VCC or GND is measured The potential drop of the direct connected pin is computed with respect to the known internal resistance of the switched port Four different measurements are made Low Pin connected to GND and High Pin connected across 680Q to VCC Low Pin connected to GND and High Pin connected across 470kQ to VCC Low Pin connected across 680Q to GND and High Pin connected to VCC Low Pin connected across 470kQ to GND and High Pin connected to VCC Corresponding to the measurement results two of the measurements are selected 680Q or 470kQ pair and the results are averaged If the AUTOSCALE_ ADC option is selected and the voltage of one result is below 0 99V an weighted average is build with factor 4 for this value the other value is weighted with factor 1 In table B2 you can see t
23. s the start button The program notice the shorten probes and start the self test function After finishing the self test the transistor tester will continue with normal measurement if no equipment is connected the program will end with part unknown or damaged The unhappy side of the self test function is that the 8K flash is used near the limit The length of the ATmega8 version 0 9k is about 8000 bytes The length of the ATmega88 version is with 8122 byte very near at the limit Use of EEprom with option USE EEPROM is one of the only possibility to save memory Some functions like ReadADC are already implemented in assembler syntax The separate steps of the self test function is generally displayed on row 1 of the LCD display with the letter T followed by the step number Every step is repeated 8 times before the program continues with the next step In every step only measurement results are displayed no error analysis are done you must interpret the results yourself At this place I will give you an additional important hint Never do a measurement with connected ISP plug The ISP interface influences the measurement Here are the Test steps 1 Measurement of the 1 3V or 1 1 V reference Voltage Band gap Reference In row 1 the text Ref and the measured Voltage in mV is displayed The second row shows the resulting factors for capacity measurement 2 Comparing of the 680Q resistors In row 1 the cryptic text L1 2 3
24. t 1 Band gap Ref 1237 Reference Voltage Signature 1E 93 07 should be 1298mV RHfakt 753 RLfakt 4887 WATE AUTO REF Test 2 RL1 RL2 RL1 RL3 RL2 RL3 comparison 680Q 2488 2488 2484 best value 2493 Test 3 RH1 RH2 RH1 RH3 RH2 RH3 comparison 470kQ 2493 2493 2493 best value 2500 isolate probe Test 5 RH1 RH2 RH3 470kQ Isolation 0 0 0 best value 0 Test 6 RHI RH2 RH3 470kQ Isolation 4995 4995 4995 best value 5001 Test 7 TP1 RLI TP2 RL2 TP3 RL3 Pin resistance Low 132 132 137 Test 8 TP2 RLI TP2 RL2 TP3 TP3 Pin resistance High 151 151 151 VCC voltage Megal68 8MHz Test 1 Band gap Ref 1090mV Reference voltage Se should be 1102mV RHfakt 865 RLfakt 5649 1E 94 06 Test 2 RLI RL2 RL1 RL3 RL2 RL3 comparison 680Q 2493 2493 2493 Test 3 RH1 RH2 RH1 RH3 RH2 RH3 comparison 470kQ 2497 2498 2498 isolate probe Test 5 RH1 RH2 RH3 470kQ Isolation 0 0 0 Test 6 RHI RH2 RH3 470kQ Isolation 4998 4998 4998 Test 7 TP1 RLI TP2 RL2 TP3 RL3 Pin resistance Low 131 132 132 Test 8 TP2 RLI TP2 RL2 TP3 TP3 Pin resistance High 156 156 156 VCC Voltage Appendix B1 Results of resistor measurements Software Version 0 92k old resistor Result of Result of Result of Mega8 1MHz Mega8 8MHz Mega88 1MHz original software Signature 1E 93 07 Signature 1E 93 0A Signature 1E 93 07 602 0 1 612 1 7 629 3
25. t of electrolytical capacitors is possible 16 Additional As you can see the list of ideas and to do tasks is still rather long My purpose is to make the transistor tester more precise faster and multifunctional Probably I purchase a second board for easier checking of different processors mega8 and megal68 I can not promise you that the task list will ever be empty Also I can not promise you that my software is free of errors I don t give you any warrenty Using my software is your own risk During my tests never a ATmega or other part was damaged But I give you the promise that I never will publish a release without source code By now I develop my software with the GNU toolchain under a Linux Ubuntu operating system I had got a useful hint from another thread on www mikrocontroller net to use my programmer Diamex ALL AVR without any problems The same programmer was not able to program the EEprom of my ATmega8 s with the Windows driver Now I can also use the original software of Markus Frejek for my tester I still hope that my software become a official version But I still wait on answer to my email to 5volt and to linuxgeek from February 2012 17
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