Hello all, I simplified the ADC library because of the changes in the ADC for the newer PICs which was not supported. It is - almost - impossible to cover for all the differences. This means that the library has been simplified and the result it that some of the configuration - like selecting the analog inputs, the reference voltage selection and the ADC clock - has to be done in the main program before the library is initialized.
I updated all 26 ADC sample files and created two new ADC sample files (for the 16F18857 and the 18F25k22) and tested 19 of them since I did not have all hardware or PICs available. You can recognize the tested sample files by the comments where the actual output of the program is mentioned. All others are compiled but could not be re-tested. I noticed that some generated sample files did not work - and could not have worked at all - so these where fixed. All sample files are now manually maintained. If you encounter any problems, let me know. Kind regards, Rob ________________________________ Van: [email protected] <[email protected]> namens Rob CJ <[email protected]> Verzonden: maandag 28 juni 2021 17:10 Aan: [email protected] <[email protected]> Onderwerp: Re: [jallib] Re: ADC library Hi Bill, Thanks for the update. Currently I made some changes to the adc library since I started modifying the sample files. I think the change has no further impact on the functionality (for some PICs I got a compile error). While modifying the 30 ADC sample files, I will test the ones for which I have a PIC - and samples that can easily be tested - and I found out that some could never have worked so I fixed those. It will take me some time before all sample files are modified. I can have a look at the 18F25K22 too and also create a sample file for that one (and for the 16F18857). Once all is done I will upload the new adc.jal and all 30 adc sample files. Kind regards, Rob ________________________________ Van: [email protected] <[email protected]> namens Bill Beek <[email protected]> Verzonden: maandag 28 juni 2021 13:59 Aan: jallib <[email protected]> Onderwerp: Re: [jallib] Re: ADC library Hello Rob and Vasile, The following PICs have also been tested with Rob's adc lib. 16F886, 18F2553, 18F2580, 26K80. No problems found so far. The 18F25K22 only worked well with the old adc lib. With the new lib 5 volts supply voltage and reference voltage could only be measured up to 2.5 volts. At a higher voltage, the value remained there. I'll have to investigate that too. I have not yet looked at the 16F1783 configuration. At 12 bits resolution the differential measurement is more suitable than single ended in my opinion, I will look at that later. At the moment I am busy with other things for the next 4 weeks. Bill On Friday, June 25, 2021 at 6:38:50 PM UTC+2 vasile wrote: Hi Bill, Rob, BTW, I don't know if you've noticed, but in all Microchip datasheet is missing the minimum value for (Vref+) -|Vref-|. Usually they presume the user is connecting Vref- to Vss and Vref+ to Vdd or to the internal reference (1.024V, 2.048V or 4.096V) or to a different one for external Vref+ mode). The Vref- can be tied to a positive voltage. On old PIC16F876 supplied at 5V, I remember the (Vref+) -|Vref-| = ~2.2V. I'm quite sure that on XLP microcontrollers supplied at minimum 1.8V this value must be much smaller. More than that, Vref- can be tied to a negative voltage of about -0.5V ( at 0.6V the protective diodes on IO pins are conducting) without degrading the ADC linearity. Again, that value is from memory, measured on PIC16F876 supplied at 5V. Bill, can you do please a test about these reference voltage values on 16F1783? thx, On Fri, Jun 25, 2021 at 6:25 PM Rob CJ <[email protected]> wrote: Hi Bill, Thanks for the update. About the 16F1783. If you look in the datasheet it say this: The CHS<4:0> bits of the ADCON0 register determine which positive channel is selected. When CHSN<3:0> = 1111 then the ADC is effectively a single ended ADC converter. These CHSN bits seems to be something extra since not al ADC has them (CHSN<3:0> are Negative Differential Input Channel Select bits). At reset, the CHSN bits are at 0, which selects AN0. So you could try to set these bits to 1111 and see if your problem is solved (1111 = ADC Negative reference - selected by ADNREF). Kind regards, Rob ________________________________ Van: [email protected] <[email protected]> namens Bill Beek <[email protected]> Verzonden: vrijdag 25 juni 2021 16:29 Aan: jallib <[email protected]> Onderwerp: Re: [jallib] Re: ADC library Hi Rob, I've tested your adc lib on several PICs so far found no problems. It concerns the following types: 16F876A, 18F2520, 18F24K50, 16F1783. The latter only works well if AN0 is connected to GND, the other 10 analog channels then work well with 12 bits of resolution.This also happens with the old adc lib, so I suspect something is wrong somewhere in myconfiguration, I'm still looking into that. I will test some other types later on. Bill. On Wednesday, June 23, 2021 at 9:12:03 AM UTC+2 [email protected] wrote: Hi Bill, Thanks for the update but I have chosen a different approach to solve the problem. Yesterday I simplified the ADC library to a basic version so that it supports more PICs and to prevent that the libary becomes too complex to support all variations of the ADC. Reason is that the library did not provide the functionality that it said it did, this because the library 'adc_channel.jal' was no longer used some time ago and so some functionality was not working because of that (like channel selection and setting the reference voltage). This simplified version makes it more generic but as I mentioned earlier, the user has to take the following steps in de main program: 1) Set the correct analog input for the used channel(s) 2) Set the correct reference voltage. I think the default is often that is used VDD as reference which works fine in most cases. 3) Set the correct AD clock using the table in the datesheet. With this change I no longer include the adc_clock.jal library and so this also works for a PIC16F18857. I attached this version to this post and if there are no objections to this change, I need to update the adc sample programs (hmm, 26 sample files to check) and test some to see if they work for different PICs. So @Jallib users. If you have any objections, let me know. Kind regards, Rob ________________________________ Van: [email protected] <[email protected]> namens Bill Beek <[email protected]> Verzonden: dinsdag 22 juni 2021 21:15 Aan: jallib <[email protected]> Onderwerp: Re: [jallib] Re: ADC library Hi Rob, I have included your piece of software in the adc_clock library library. After I defined the variables everything worked properly. Of course I have the ADC_ADCS_BITCOUNT set back to 1 in the 16F18857 lib. The FRC clock signal is now used, which is also my preference. As far as I'm concerned, this chapter is closed Thanks again to all who contributed ideas and made suggestions. Bill. On Tuesday, June 22, 2021 at 7:17:59 AM UTC+2 vasile wrote: Hi Rob, this wasn't a request. I never used the ADC library from the jalpack even though I have read it and tried to understand it's philosophy. But you have perfectly defined my way of working with ADC. So it's up to jal users requests and finally on your own wish. best wishes, On Mon, Jun 21, 2021 at 8:18 PM Rob CJ <[email protected]> wrote: Hi Vasile, Thanks for the feedback. I agree with you that a basic ADC library is better than nothing. I think the Tad calculation is making it more beautiful but requires also more space than needed (since it calculates for different target clocks). The basic ADC library would then only start a conversion and return the result. The user of the library should then take care of the following 3 items which can be mentioned in the adc.jal library and the sample program: 1) Set the correct analog input for the used channel 2) Set the correct reference voltage. I think the default is often that is used VDD as reference which works fine. 3) Set the correct AD clock (Tad) using the table in the datesheet. I think if you do not set this it will still work OK. If we would go this way, the whole Tad calculation (adc_clock.jal) could be removed (sorry Rob Hamerling) and adc.jal could be simplified. Kind regards, Rob ________________________________ Van: [email protected] <[email protected]> namens vsurducan <[email protected]> Verzonden: maandag 21 juni 2021 18:50 Aan: [email protected] <[email protected]> Onderwerp: Re: [jallib] Re: ADC library Rob, the library does not need to compute the TAD, that was introduced first by a french jallian (i think it was Sebastien Lelong) who tried to write an universal ADC library ( and for a short time it works). You have only to choose one of the recommended ranges. The ADC will work very well with several different clocks... As a PIC user, performing an ADC without reading the microcontroller datasheet...and letting the library do everything for you just to be easy seems weird. best wishes, On Mon, Jun 21, 2021 at 6:28 PM Rob CJ <[email protected]> wrote: Hi Bill, I looked into some more details of the library and I think understand why it works for you. Since you use the defaults of the PIC after reset and you changed ADC_ADCS_BITCOUNT to 2 the program compiles and runs but the clock selection that is calculated by the library does not work correctly for the PIC you are using. I am not sure what the ADC clock settings are used now but it may be that your ADC now uses a clock source of fosc/2 since a clock register is set to 0 (this PIC is different from the other PICs since is uses a separate register for the clock of the ADC and that is why it has the setting of 1 instead of 2 and 3). If you are using fosc/2 then according to the datasheet you may be using it out of spec. see table below with a clock frequency of 20 MHz. [X] The clock register for your PIC is defined as follows: [X] I was working on an update of the library but got stuck with the clock adc_clock part that calculates the Tad. Maybe somebody else knows what goes wrong in the code below (it always results in the warning that the clock speed is too high as if the dword 'value' is not calculated correctly). It also results in quite some rom space which I do not like. I wonder why we would not simplify the libary and always use FRC since that is always correct according to the table above. It would make the adc library simpler since adc_clock.jal library st no longer needed. If somebody has any idea why not to do that, let me know. elsif (ADC_ADCS_BITCOUNT == 1) then -- target has separate clock selection register counter = 0 done = FALSE ADCON0_ADCS = FALSE -- use ADCLK register repeat value = (2 * dword(counter + 1) * 10_000_000) / target_clock if value >= ADC_MIN_TAD then tad_word = word(value) jallib_adcs = counter done = TRUE end if counter = counter + 1 until done | (counter == 64) if !done then _warn "\n\tClock speed too high for Tad, internal ADC oscillator (Frc) selected" tad_word = 40 -- (approx) ADCON0_ADCS = TRUE -- use Frc end if Kind regards, Rob ________________________________ Van: [email protected] <[email protected]> namens Bill Beek <[email protected]> Verzonden: maandag 21 juni 2021 16:22 Aan: jallib <[email protected]> Onderwerp: [jallib] Re: ADC library Hi Rob, After your post I looked even further, I use the latest adc lib and tested the first 10 adc channels. they work all the time, and are relatively accurate. I also looked at the adc_clock lib and tried to adjust the code. The 18857 only has 1 clock selection bit "FRC or crystal controlled" , but it didn't work yet. For now, I'm happy with the result. Here's a piece of the program I used. const bit ADC_HIGH_RESOLUTION = true const byte ADC_NCHANNEL = 2 const byte ADC_NVREF = ADC_NO_EXT_VREF include adc adc_init() var word measure var word voltage var byte lowmeasure const byte prefix[] = "Channel " const byte highstr[] = " (high) " const byte lowstr[] = " (low) " const byte suffix[] = ": " const byte value[] = " U = " const byte units[] = " Volts." forever loop var byte channel = 0 -- loop over all channels and read led = !led for 11 using channel loop -- get ADC result, high resolution measure = adc_read_high_res(channel) -- send it back through serial print_string(serial_hw_data,prefix) print_string(serial_hw_data,highstr) print_byte_dec(serial_hw_data,channel) print_string(serial_hw_data,suffix) -- print_word_bin(serial_hw_data,measure) ; this one works ! print_word_dec(serial_hw_data,measure) ; I should get ~512 voltage = measure * 0.4883 -- 5 V / 1024 * 100 (for 2 decimals) print_string(serial_hw_data,value) --print_word_dec(serial_hw_data,voltage) --print_string(serial_hw_data,value) format_word_dec(serial_hw_data,voltage,5,2) -- decimal 2 = /100 print_string(serial_hw_data,units) print_crlf(serial_hw_data) delay_1ms(250) -- Even if we set high resolution, we can still access results -- in low resolution (the 2 LSb will be removed) lowmeasure = adc_read_low_res(channel) print_string(serial_hw_data,prefix) print_string(serial_hw_data,lowstr) print_byte_dec(serial_hw_data,channel) print_string(serial_hw_data,suffix) print_byte_dec(serial_hw_data,lowmeasure) ; I should get ~127 print_crlf(serial_hw_data) -- and sleep a litte... --led = OFF delay_1ms(2500) end loop end loop Kind regards Bill. On Thursday, June 17, 2021 at 3:56:36 PM UTC+2 Bill Beek wrote: Hello all, When I tried to do a test with analog input on the 16F18857 I found that the library adc.jal gave 7 errors. In particular, the "adcon0_chs" was not recognized. The lib of the 16F18857 does recognize it the "adcon0_adcs" . It seems that some newer MCU's have this problem as well. After a change of the adc lib a new error occurred, _error "Found unsupported value for constant ADC_ADCS_BITCOUNT". Does anyone else have experience with this event or know a solution? Thanks, Bill -- You received this message because you are subscribed to the Google Groups "jallib" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. 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