Hey all, Problem solved. Had to redo all ADC code. Here is the working code. Maybe this is usefull for the coders here;
-- ok, now let's configure ADC pin_AN0_direction = input -- ADCON0 CONFIG ADCON0_CHS0 = OFF -- Channel at 0 (Bit 0) ADCON0_CHS1 = OFF -- Channel at 0 (Bit 1) ADCON0_CHS2 = OFF -- Channel at 0 (Bit 2) ADCON0_CHS3 = OFF -- Channel at 0 (Bit 3) -- ADCON1 CONFIG ADCON1_PCFG0 = OFF -- AN0 as Analog ONLY (Bit 0) ADCON1_PCFG1 = ON -- AN0 as Analog ONLY (Bit 1) ADCON1_PCFG2 = ON -- AN0 as Analog ONLY (Bit 2) ADCON1_PCFG3 = ON -- AN0 as Analog ONLY (Bit 3) ADCON1_VCFG0 = OFF -- Vref+ at VDD ADCON1_VCFG1 = OFF -- Vref- at VSS -- ADCON2 CONFIG ADCON2_ADCS0 = OFF -- AD Conversion Clock at Fosc/64 (Bit 0) ADCON2_ADCS1 = ON -- AD Conversion Clock at Fosc/64 (Bit 1) ADCON2_ADCS2 = ON -- AD Conversion Clock at Fosc/64 (Bit 2) ADCON2_ACQT0 = ON -- AD Acq. Time at 2xTAD (Bit 0) ADCON2_ACQT1 = OFF -- AD Acq. Time at 2xTAD (Bit 1) ADCON2_ACQT2 = OFF -- AD Acq. Time at 2xTAD (Bit 2) ADCON2_ADFM = ON -- AD Result Justify at Right -- const word ADC_RSOURCE = 2_500 -- Input Resistance const byte ADC_TEMP = 85 -- PIC Max. Temperature const byte ADC_MAX_TAD = 6 -- (0.8us < TAD < 12.5us as per -- Datasheet, Pag. 41) -- AD ACQUISITION TIME (Original VAR: adc_conversion_delay) -- Tacq = Tamp + Tc + Tcoff const word tamp = 1 -- (=> 0.2us as per Datasheet, Pag. 30) const word adc_tc = 2 -- ((TEMP – 25°C)x(0.02 us/°C) => 1.2us as per Datasheet, Pag. 30)) const word adc_tcoff = 2 -- (-(25 pF)x(1 kohm + 4 kohm + RSOURCE)xln(0.0004883) -- => 1.56us as per Datasheet, Pag. 30) const byte ADC_TACQ = byte(tamp + adc_tc + adc_tcoff) -- (Original VAR: adc_conversion_delay) -- var word adc_word -- return value var byte adc_byte[2] at adc_word -- byte array overlay -- function adc_read_high_res(byte in adc_chan) return word is pragma inline -- -- Original Code has here the Channel and L/R Justifying -- These parameters are set above... -- ADCON0_ADON = TRUE -- turn on ADC module -- for ADC_TACQ loop _usec_delay(1) -- wait acquisition time -- Original: _usec_delay(10) end loop -- ADCON0_GO = TRUE -- start conversion while ADCON0_GO == TRUE loop -- wait until conversion completed -- Empty loop. end loop -- adc_byte[1] = ADRESH -- copy high order bits adc_byte[0] = ADRESL -- copy low order bits -- Choosed High Resolution options here, from Original Code... -- -- Honor 2 * max Tad time. Note the value is not very accurate, but safe. _usec_delay(2 * ADC_MAX_TAD) -- As per Datasheet, Pag. 29 -- ADCON0_ADON = false -- turn off ADC module return adc_word -- back to caller end function Best regrads, FS On Wednesday, September 14, 2022 at 1:43:19 PM UTC+1 flyway38 wrote: > Hello Vasile, > > Thank you for your input. > About Vref it should be set to VCC (5V) and GND. It's the default anyways > (by the Datasheet info). > Have, however, noticed that the ADC initial configuration constants don't > match with the needed ones. > EX: ANSEL_ADCS, ADCON0_VCFG, ANSEL_ANS0, etc.. aren't used in ADC lib or > even in PIC(18F2523) lib. > > About convertion time and MAX_TAD, have already tested longer time values > with no sucess... > Any more ideas? > Thanks anyways. > > Cheers, > Filipe Santos. > > On Wednesday, September 14, 2022 at 12:57:26 PM UTC+1 vasile wrote: > >> If your Vref + is +5V and Vref- is GND, full scale means 4095 at 5V. >> One issue might appear if acquisition time is too short or you have >> messed something with references. >> |Vref+| - |Vref-| >=3V >> >> On Tue, Sep 13, 2022 at 4:54 PM flyway38 <fsfo...@gmail.com> wrote: >> >>> Hello all, >>> >>> New question. >>> My PIC is reading ok ADC values if below 2.5V (1/2 of range VCC/GND). >>> It seems like 11bit ADC behaviour. >>> >>> My code: >>> -- ok, now let's configure ADC >>> -- Step 1: ADC analog input pin setup >>> const byte ADC_CHANNEL = 0 -- port 0 is analog >>> input (default) >>> pin_AN0_direction = input >>> const byte ANSEL_ANS0 = TRUE -- potmeter connected >>> to pin_AN0 >>> -- Step 2: Set VDD and VSS as Vref >>> const byte ADCON0_VCFG = FALSE >>> -- Step 3: Use Frc as ADC clock >>> const byte ANSEL_ADCS = 0b110 >>> -- >>> const ADC_RSOURCE = 500 -- Input Resistance >>> const ADC_TEMP = 20 -- PIC Temperature >>> -- We want the fastest possible ADC timing, so we specify here the >>> --const ADC_MIN_TAD = 1 >>> const ADC_MAX_TAD = 10 >>> -- Now we can include the library >>> include adc >>> -- And initialize the whole with our parameters >>> adc_init() >>> >>> Inside Forever Loop: >>> iVal = 0 -- Its a DWord >>> -- >>> for AdcReadings loop >>> AdcData = adc_read_high_res(AdcChnn) >>> iVal = iVal + dword(AdcData) >>> end loop >>> -- >>> mVal = word(iVal / dword(AdcReadings)) >>> >>> Any help would be great. >>> Thank you very much. >>> >>> Kind regrads, >>> Filipe Santos >>> >>> -- >>> 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 jallib+un...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/jallib/5c020fb1-f8fa-4684-9284-1dc3a1793ca4n%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/jallib/5c020fb1-f8fa-4684-9284-1dc3a1793ca4n%40googlegroups.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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