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. [https://groups.google.com/group/jallib/attach/3f9dd711b5998/image.png?part=0.2&view=1] The clock register for your PIC is defined as follows: [https://groups.google.com/group/jallib/attach/3f9dd711b5998/image.png?part=0.1&view=1] 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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adc.jal
Description: adc.jal
