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. >> >> >> >> The clock register for your PIC is defined as follows: >> >> >> 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\t >> Clock 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]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/jallib/fb841324-9302-4429-b6ce-bf91a8cc5ed2n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/jallib/fb841324-9302-4429-b6ce-bf91a8cc5ed2n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> >> -- >> 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]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/jallib/AM0PR07MB6241CE5B558BCB2464E7B2AEE60A9%40AM0PR07MB6241.eurprd07.prod.outlook.com >> >> <https://groups.google.com/d/msgid/jallib/AM0PR07MB6241CE5B558BCB2464E7B2AEE60A9%40AM0PR07MB6241.eurprd07.prod.outlook.com?utm_medium=email&utm_source=footer> >> . >> >> -- >> 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]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/jallib/CAM%2Bj4qu%2B4yTSgaMF7V_0%3DEf8ypCOtrenVvJ3xxXwSFuCBxubOw%40mail.gmail.com >> >> <https://groups.google.com/d/msgid/jallib/CAM%2Bj4qu%2B4yTSgaMF7V_0%3DEf8ypCOtrenVvJ3xxXwSFuCBxubOw%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> >> -- >> 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]. >> > To view this discussion on the web visit >> https://groups.google.com/d/msgid/jallib/AM0PR07MB62416C19816AE39CC900C31DE60A9%40AM0PR07MB6241.eurprd07.prod.outlook.com >> >> <https://groups.google.com/d/msgid/jallib/AM0PR07MB62416C19816AE39CC900C31DE60A9%40AM0PR07MB6241.eurprd07.prod.outlook.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "jallib" group. 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