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Re: SOLVED: How can I reduce ADC drift
and to be sure, use a resistor divider with cap of 1uF to ground from the tap point to ADC, instead of POT. If your results are stable then you can replace with a pot and see if the problem is the pot itself.
Ioannis
p.s. corrected the drift to jitter on the Thread title
Last edited by Ioannis; - 5th March 2025 at 19:38.
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Re: SOLVED: How can I reduce ADC jitter
Oh I still get jitter at 1023 or ">> 1". I'm running at ">> 2" and had to use Vref- (3R/1K) cause I was having some instability at the 0 end of scale. The pots already have a slight deadzone under 5% and above 95% (look at the chart above - that was from manuf spec sheet).
I only have a resolution of 256, with a maximum of 88 detents because I TX with changes in ADC larger than 2. But I'm still happy because this is good enough for my application (so far).
TX:
Code:#CONFIG __config _CONFIG1, _FEXTOSC_OFF & _RSTOSC_HFINT32 & _CLKOUTEN_OFF & _CSWEN_OFF & _FCMEN_ON __config _CONFIG2, _MCLRE_ON & _PWRTE_OFF & _LPBOREN_OFF & _BOREN_ON & _BORV_LO & _ZCD_OFF & _PPS1WAY_OFF & _STVREN_ON & _DEBUG_OFF __config _CONFIG3, _WDTCPS_WDTCPS_11 & _WDTE_OFF & _WDTCWS_WDTCWS_7 & _WDTCCS_LFINTOSC __config _CONFIG4, _WRT_OFF & _SCANE_available & _LVP_OFF __config _CONFIG5, _CP_OFF & _CPD_OFF #ENDCONFIG ;--- Interrupts ---------------------------------------------------------------- include "I:\Project_v2\PBP\PBP_Includes\DT_INTS-14_16F1885x-7x.bas" include "I:\Project_v2\PBP\PBP_Includes\ReEnterPBP.bas" ASM INT_LIST macro ; IntSource, Label, Type, ResetFlag? INT_Handler RX_INT, _RXInterrupt, PBP, no endm INT_CREATE ; Creates the interrupt processor ENDASM DEFINE OSC 32 DEFINE ADC_BITS 10 ' 10-bit Analog to digital DEFINE ADC_SAMPLEUS 5 ' Set sampling time in uS DEFINE HSER_RXREG PORTC DEFINE HSER_RXBIT 7 DEFINE HSER_TXREG PORTC DEFINE HSER_TXBIT 6 DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive DEFINE HSER_TXSTA 24h ' Enable transmit, BRGH = 1 Define HSER_BAUD 115200 DEFINE HSER_CLROERR 1 ' Clear overflow automatically DEFINE HSER_SPBRGH 0 DEFINE HSER_SPBRG 68 define CCP1_REG 0 ' Must clear unused CCP pins or else unpredictable results DEFINE CCP1_BIT 0 define CCP2_REG 0 DEFINE CCP2_BIT 0 define CCP3_REG 0 DEFINE CCP3_BIT 0 define CCP4_REG 0 DEFINE CCP4_BIT 0 define CCP5_REG 0 DEFINE CCP5_BIT 0 ;--- Setup registers ----------------------------------------------------------- BAUDCON.3 = 1 ' Enable 16 bit baudrate generator INTCON = %11000000 ' INTERRUPT CONTROL REGISTER ' bit 7 GIE: Global Interrupt Enable bit ' 1 = Enables all active interrupts ' 0 = Disables all interrupts ' bit 6 PEIE: Peripheral Interrupt Enable bit ' 1 = Enables all active peripheral interrupts ' 0 = Disables all peripheral interrupts PIE3 = %00100000 ' PERIPHERAL INTERRUPT ENABLE REGISTER 3 ' bit 5 RCIE: USART Receive Interrupt Enable bit ' 1 = Enables the USART receive interrupt ' 0 = Enables the USART receive interrupt PIR3 = %00000000 ' PERIPHERAL INTERRUPT REQUEST REGISTER 3 ' bit 5 RCIF: EUSART Receive Interrupt Flag (read-only) bit (1) ' 1 = The EUSART receive buffer is not empty (contains at least one byte) ' 0 = The EUSART receive buffer is empty FVRCON = %0000000 ' FIXED VOLTAGE REFERENCE CONTROL REGISTER ' bit 7 FVREN: Fixed Voltage Reference Enable bit ' 1 = Fixed Voltage Reference is enabled ' bit 1-0 ADFVR<1:0>: ADC FVR Buffer Gain Selection bit ' 11 = ADC FVR Buffer Gain is 4x, (4.096V)(2) ADCON0 = %10000100 ' ADC CONTROL REGISTER 0 ' bit 7 ADON: ADC Enable bit ' 1 = ADC is enabled ' bit 2 ADFRM0: ADC results Format/alignment Selection ' 1 = ADRES and ADPREV data are right-justified ADCON2 = %00000000 ' ADC CONTROL REGISTER 2 ' bit 2-0 ADMD<2:0>: ADC Operating Mode Selection bits(1) ' 000 = Basic (Legacy) mode ADCLK = %00001111 ' ADC CLOCK SELECTION REGISTER ' bit 5-0 ADCCS<5:0>: ADC Conversion Clock Select bits ' 1111 = FOSC/32 ADREF = %00010000 ' ADC REFERENCE SELECTION REGISTER ' bit 4 ADNREF: ADC Negative Voltage Reference Selection bit ' 1 = VREF- is connected to VREF- pin ' 0 = VREF- is connected to AVSS ' bit 1-0 ADPREF: ADC Positive Voltage Reference Selection bits ' 11 = VREF+ is connected to FVR_buffer 1 ' 10 = VREF+ is connected to VREF+ pin ' 00 = VREF+ is connected to VDD ADPCH = %00000000 ' ADC POSITIVE CHANNEL SELECTION REGISTER ' 000000 = ANA0 WPUA = %01100000 ' Pin A7 = ADC-A0 debug ' Pin A4 = ADC-A4 (B10K) ' Pin A3 = SW external pull-down ' Pin A2 = Vref- ' Pin A1 = ADC-A1 (B5K w/SW) ' Pin A0 = ADC-A0 (B5K) WPUB = %11111111 WPUC = %00100111 ' Pin C7 = RX ' Pin C6 = TX ' Pin C4 = ADC-C4 (B10K) ' Pin C3 = ADC-C3 (B10K) ANSELA = %00010011 ' Pin A4 = ADC-A4 (B10K) ' Pin A1 = ADC-A1 (B5K w/SW) ' Pin A0 = ADC-A0 (B5K) ANSELB = %00000000 ANSELC = %00011000 ' Pin C7 = RX ' Pin C6 = TX ' Pin C4 = ADC-C4 (B10K) ' Pin C3 = ADC-C3 (B10K) TRISA = %00011011 ' Pin A7 = ADC-A0 debug ' Pin A4 = ADC-A4 (B10K) ' Pin A3 = SW ' Pin A1 = ADC-A1 (B5K w/SW) ' Pin A0 = ADC-A0 (B5K) TRISB = %00000000 ' Pin B7 = ...not available, ICSPDAT ' Pin B6 = ...not available, ICSPCLK TRISC = %11011000 ' Pin C7 = RX *** Datasheet requirement, INPUT *** ' Pin C6 = TX *** Datasheet requirement, INPUT *** ' Pin C4 = ADC-C4 (B10K) ' Pin C3 = ADC-C3 (B10K) A0debug var LATA.7 SW var PORTA.3 MsgData var byte[3] MsgCode VAR BYTE ADCinput var WORD ADCcalc var WORD ADCdiff var WORD ADCchange var byte ShiftRight var byte OldADC var WORD OldADC_A0 var WORD OldADC_A1 var WORD OldADC_A4 var WORD OldADC_C3 var WORD OldADC_C4 var WORD OldSW var BYTE RXoccurred var BYTE A0debug = 0 RXoccurred = 0 ' Clear RX flag @ INT_ENABLE RX_INT ; Enable USART Receive interrupts Pause 1500 ' Let PIC and LCD stabilize goto Start ;--- Interrupts ---------------------------------------------------------------- RXInterrupt: hserin [ STR MsgData\3 ] while BAUDCON1.6 = 0 ' Check RCIDL bit wend RXoccurred = 1 ' Set flag @ INT_RETURN ;--- Subroutines --------------------------------------------------------------- SendData: hserout [ MsgData[0], MsgData[1], MsgData[2] ] while TX1STA.1 = 0 ' Check TRMT bit wend while RXoccurred = 0 ' Check for interrupt wend RXoccurred = 0 ' Set flag ADCchange = 1 RETURN ProcessADC: ADCchange = 0 if ADCcalc < oldADC then ADCdiff = oldADC - ADCcalc else ADCdiff = ADCcalc - oldADC endif IF ADCdiff > 2 then ' Check for Diff over 2 MsgData[0] = MsgCode if ADCcalc <> oldADC then ' ADC value changed MsgData[1] = ADCcalc.byte1 : MsgData[2] = ADCcalc.byte0 GOSUB SendData endif ELSE IF ADCdiff > 0 then ' Check for Diff over 0 if ADCcalc = 0 then ' Reached end of rotation MsgData[1] = ADCcalc.byte1 : MsgData[2] = ADCcalc.byte0 GOSUB SendData ELSE if ADCcalc = 255 then ' Reached end of rotation MsgData[1] = ADCcalc.byte1 : MsgData[2] = ADCcalc.byte0 GOSUB SendData endif endif endif endif RETURN Start: ADCinput = 0 : ADCdiff = 0 : ADCcalc = 0 OldADC_A0 = 9999 : OldADC_A1 = 9999 : OldADC_A4 = 9999 : OldADC_C3 = 9999 : OldADC_C4 = 9999 OldSW = 9 ShiftRight = 2 Mainloop: rem ADC A0 test MsgCode = 0 adcin 0, ADCinput ADCcalc = ADCinput >> ShiftRight oldADC = OldADC_A0 gosub ProcessADC if ADCchange = 1 then A0debug = 1 OldADC_A0 = ADCcalc A0debug = 0 endif rem ADC A1 test MsgCode = 1 adcin 1, ADCinput ADCcalc = ADCinput >> ShiftRight oldADC = OldADC_A1 gosub ProcessADC if ADCchange = 1 then OldADC_A1 = ADCcalc endif rem SW A3 MsgCode = 3 if SW <> oldSW then oldSW = SW MsgData[0] = MsgCode : MsgData[1] = oldSW :MsgData[2] = " " GOSUB SendData endif rem ADC A4 test MsgCode = 4 adcin 4, ADCinput ADCcalc = ADCinput >> ShiftRight oldADC = OldADC_A4 gosub ProcessADC if ADCchange = 1 then OldADC_A4 = ADCcalc endif rem ADC C3 test MsgCode = 5 adcin 19, ADCinput ADCcalc = ADCinput >> ShiftRight oldADC = OldADC_C3 gosub ProcessADC if ADCchange = 1 then OldADC_C3 = ADCcalc endif rem ADC C4 test MsgCode = 6 adcin 20, ADCinput ADCcalc = ADCinput >> ShiftRight oldADC = OldADC_C4 gosub ProcessADC if ADCchange = 1 then OldADC_C4 = ADCcalc endif GOTO Mainloop end
RX:
Code:#CONFIG __config _CONFIG1, _FEXTOSC_OFF & _RSTOSC_HFINT32 & _CLKOUTEN_OFF & _CSWEN_OFF & _FCMEN_ON __config _CONFIG2, _MCLRE_ON & _PWRTE_OFF & _LPBOREN_OFF & _BOREN_ON & _BORV_LO & _ZCD_OFF & _PPS1WAY_OFF & _STVREN_ON & _DEBUG_OFF __config _CONFIG3, _WDTCPS_WDTCPS_11 & _WDTE_OFF & _WDTCWS_WDTCWS_7 & _WDTCCS_LFINTOSC __config _CONFIG4, _WRT_OFF & _SCANE_available & _LVP_OFF __config _CONFIG5, _CP_OFF & _CPD_OFF #ENDCONFIG ;--- Interrupts ---------------------------------------------------------------- include "I:\Project_v2\PBP\PBP_Includes\DT_INTS-14_16F1885x-7x.bas" include "I:\Project_v2\PBP\PBP_Includes\ReEnterPBP.bas" ASM INT_LIST macro ; IntSource, Label, Type, ResetFlag? INT_Handler RX_INT, _RXInterrupt, PBP, no endm INT_CREATE ; Creates the interrupt processor ENDASM DEFINE OSC 32 DEFINE LCD_DREG PORTB ' Set LCD data port DEFINE LCD_DBIT 0 ' Set starting data bit DEFINE LCD_RSREG PORTC ' Set LCD register select port DEFINE LCD_RSBIT 4 ' Set LCD register select bit DEFINE LCD_EREG PORTC ' Set LCD enable port DEFINE LCD_EBIT 5 ' Set LCD enable bit DEFINE LCD_BITS 4 ' Set LCD bus size DEFINE LCD_LINES 4 ' Set number of lines on LCD DEFINE LCD_COMMANDUS 1000 ' Set command delay time in microseconds DEFINE LCD_DATAUS 50 ' Set data delay time in microseconds define CCP1_REG 0 ' Must clear unused CCP pins or else unpredictable results DEFINE CCP1_BIT 0 define CCP2_REG 0 DEFINE CCP2_BIT 0 define CCP3_REG PORTB ' PWM Pulse out to LCD backlight DEFINE CCP3_BIT 5 define CCP4_REG 0 ' Must clear unused CCP pins or else unpredictable results DEFINE CCP4_BIT 0 define CCP5_REG PORTA ' PWM Pulse out to LED strips DEFINE CCP5_BIT 4 DEFINE HSER_RXREG PORTC DEFINE HSER_RXBIT 7 DEFINE HSER_TXREG PORTC DEFINE HSER_TXBIT 6 DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive DEFINE HSER_TXSTA 24h ' Enable transmit, BRGH = 1 Define HSER_BAUD 115200 DEFINE HSER_CLROERR 1 ' Clear overflow automatically DEFINE HSER_SPBRGH 0 DEFINE HSER_SPBRG 68 ;--- Setup registers ----------------------------------------------------------- BAUDCON.3 = 1 ' Enable 16 bit baudrate generator INTCON = %11000000 ' INTERRUPT CONTROL REGISTER ' bit 7 GIE: Global Interrupt Enable bit ' 1 = Enables all active interrupts ' 0 = Disables all interrupts ' bit 6 PEIE: Peripheral Interrupt Enable bit ' 1 = Enables all active peripheral interrupts ' 0 = Disables all peripheral interrupts PIE3 = %00100000 ' PERIPHERAL INTERRUPT ENABLE REGISTER 3 ' bit 5 RCIE: USART Receive Interrupt Enable bit ' 1 = Enables the USART receive interrupt ' 0 = Enables the USART receive interrupt PIR3 = %00000000 ' PERIPHERAL INTERRUPT REQUEST REGISTER 3 ' bit 5 RCIF: EUSART Receive Interrupt Flag (read-only) bit (1) ' 1 = The EUSART receive buffer is not empty (contains at least one byte) ' 0 = The EUSART receive buffer is empty CCP3CON = %10001111 ' CCP3 CONTROL REGISTER ' bit 7 EN: CCPx Module Enable bit ' 1 = CCPx is enabled ' bit 4 FMT: CCPW (Pulse Width) Alignment bit ' MODE = PWM mode ' 0 = Right-aligned format ' bit 3-0 MODE<3:0>: CCPx Mode Select bits(1) ' 1111 = PWM mode CCP5CON = %10001111 ' CCP5 CONTROL REGISTER ' bit 7 EN: CCPx Module Enable bit ' 1 = CCPx is enabled ' bit 4 FMT: CCPW (Pulse Width) Alignment bit ' MODE = PWM mode ' 0 = Right-aligned format ' bit 3-0 MODE<3:0>: CCPx Mode Select bits(1) ' 1111 = PWM mode ADCON0 = %00000000 ' ADC CONTROL REGISTER 0 WPUA = %11101111 ' Pin A7 = ADC-A0 debug WPUB = %11011111 WPUC = %00111111 ANSELA = %00000000 ANSELB = %00000000 ANSELC = %00000000 TRISA = %00000000 ' Pin A7 = ADC-A0 debug ' Pin A4 = PWM to LED strips TRISB = %00000000 ' Pin B7 = ...not available, ICSPDAT ' Pin B6 = ...not available, ICSPCLK ' Pin B5 = PWM to LCD backlight TRISC = %11000000 ' Pin C7 = RX *** Datasheet requirement, INPUT *** ' Pin C6 = TX *** Datasheet requirement, INPUT *** A0debug var LATA.7 MsgData var byte[3] MsgCode VAR BYTE MsgADC_A0 VAR WORD MsgADC_A1 VAR WORD MsgADC_A4 VAR WORD MsgADC_C3 VAR WORD MsgADC_C4 VAR WORD MsgSW VAR BYTE SWtext VAR BYTE[2] HPWMlcdBL var BYTE HPWMledstripe var BYTE DefaultLcdBL var BYTE DefaultLedstripe var BYTE RXoccurred var BYTE A0debug = 0 HPWMlcdBL = 255 ' OFF HPWMledstripe = 0 ' OFF HPWM 3, HPWMlcdBL, 1953 HPWM 5, HPWMledstripe, 1953 RXoccurred = 0 ' Clear RX flag Pause 200 ' Let PIC and LCD stabilize goto Start ' Jump over sub-routines ;--- Interrupts ---------------------------------------------------------------- RXInterrupt: hserin [ STR MsgData\3 ] ' while BAUDCON1.6 = 0 ' Check RCIDL bit ' wend RXoccurred = 1 ' Set flag @ INT_RETURN ;--- Subroutines --------------------------------------------------------------- SendConfirmation: hserout [ MsgData[0], MsgData[1], MsgData[2] ] ' while TX1STA.1 = 0 ' Check TRMT bit ' wend RETURN ProcessADC_A0: A0debug = 1 MsgADC_A0.byte1 = MsgData[1] : MsgADC_A0.byte0 = MsgData[2] LCDOUT $FE, $C0+3, DEC4 MsgADC_A0 RXoccurred = 0 ' Clear RX flag HPWMlcdBL = MsgADC_A0 HPWM 3, HPWMlcdBL, 1953 MsgData[0] = MsgCode : MsgData[1] = "O" : MsgData[2] = "K" gosub SendConfirmation LCDOUT $FE, $C0+8, "x" : LCDOUT $FE, $C0+19, " " LCDOUT $FE, $94+8, " " : LCDOUT $FE, $94+19, " " LCDOUT $FE, $D4+8, " " : LCDOUT $FE, $D4+19, " " A0debug = 0 RETURN ProcessADC_A1: MsgADC_A1.byte1 = MsgData[1] : MsgADC_A1.byte0 = MsgData[2] LCDOUT $FE, $94+3, DEC4 MsgADC_A1 RXoccurred = 0 ' Clear RX flag HPWMledstripe = 255 - MsgADC_A1 ' Invert value HPWM 5, HPWMledstripe, 1953 MsgData[0] = MsgCode : MsgData[1] = "O" : MsgData[2] = "K" gosub SendConfirmation LCDOUT $FE, $C0+8, " " : LCDOUT $FE, $C0+19, " " LCDOUT $FE, $94+8, "x" : LCDOUT $FE, $94+19, " " LCDOUT $FE, $D4+8, " " : LCDOUT $FE, $D4+19, " " RETURN ProcessSW3: if MsgData[1] = 0 then SWtext[0] = "O" : SWtext[1] = "f" : SWtext[2] = "f" ELSE SWtext[0] = "O" : SWtext[1] = "n" : SWtext[2] = " " ENDIF LCDOUT $FE, $D4+3, SWtext[0], SWtext[1], SWtext[2], " " RXoccurred = 0 ' Clear RX flag MsgData[0] = MsgCode : MsgData[1] = "O" : MsgData[2] = "K" gosub SendConfirmation LCDOUT $FE, $C0+8, " " : LCDOUT $FE, $C0+19, " " LCDOUT $FE, $94+8, " " : LCDOUT $FE, $94+19, " " LCDOUT $FE, $D4+8, "x" : LCDOUT $FE, $D4+19, " " RETURN ProcessADC_A4: MsgADC_A4.byte1 = MsgData[1] : MsgADC_A4.byte0 = MsgData[2] RXoccurred = 0 ' Clear RX flag LCDOUT $FE, $C0+14, DEC4 MsgADC_A4 MsgData[0] = MsgCode : MsgData[1] = "O" : MsgData[2] = "K" gosub SendConfirmation LCDOUT $FE, $C0+8, " " : LCDOUT $FE, $C0+19, "x" LCDOUT $FE, $94+8, " " : LCDOUT $FE, $94+19, " " LCDOUT $FE, $D4+8, " " : LCDOUT $FE, $D4+19, " " RETURN ProcessADC_C3: MsgADC_C3.byte1 = MsgData[1] : MsgADC_C3.byte0 = MsgData[2] RXoccurred = 0 ' Clear RX flag LCDOUT $FE, $94+14, DEC4 MsgADC_C3 MsgData[0] = MsgCode : MsgData[1] = "O" : MsgData[2] = "K" gosub SendConfirmation LCDOUT $FE, $C0+8, " " : LCDOUT $FE, $C0+19, " " LCDOUT $FE, $94+8, " " : LCDOUT $FE, $94+19, "x" LCDOUT $FE, $D4+8, " " : LCDOUT $FE, $D4+19, " " RETURN ProcessADC_C4: MsgADC_C4.byte1 = MsgData[1] : MsgADC_C4.byte0 = MsgData[2] RXoccurred = 0 ' Clear RX flag LCDOUT $FE, $D4+14, DEC4 MsgADC_C4 MsgData[0] = MsgCode : MsgData[1] = "O" : MsgData[2] = "K" gosub SendConfirmation LCDOUT $FE, $C0+9, " " : LCDOUT $FE, $C0+19, " " LCDOUT $FE, $94+9, " " : LCDOUT $FE, $94+19, " " LCDOUT $FE, $D4+9, " " : LCDOUT $FE, $D4+19, "x" RETURN Start: HPWMlcdBL = 150 HPWMledstripe = 150 MsgADC_A0 = 0 MsgADC_A1 = 0 MsgADC_A4 = 0 MsgADC_C3 = 0 MsgADC_C4 = 0 MsgSW = 0 HPWM 3, HPWMlcdBL, 1953 HPWM 5, HPWMledstripe, 1953 LCDOUT $FE, 1 LCDOUT $FE, $80, " ADC TEST with SW " LCDOUT $FE, $C0, "A0:____ _ A4:____ _" LCDOUT $FE, $94, "A1:____ _ C3:____ _" LCDOUT $FE, $D4, "SW:____ _ C4:____ _" @ INT_ENABLE RX_INT ; Enable USART Receive interrupts Mainloop: while RXoccurred = 0 ' Check for interrupt wend MsgCode = MsgData[0] if MsgCode = 0 then gosub ProcessADC_A0 else if MsgCode = 1 then gosub ProcessADC_A1 else if MsgCode = 3 then gosub ProcessSW3 else if MsgCode = 4 then gosub ProcessADC_A4 else if MsgCode = 5 then gosub ProcessADC_C3 else if MsgCode = 6 then gosub ProcessADC_C4 endif endif endif endif endif endif GOTO Mainloop end
My Creality Ender 3 S1 Plus is a giant paperweight that can't even be used as a boat anchor, cause I'd be fined for polluting our waterways with electronic devices.
Not as dumb as yesterday, but stupider than tomorrow!
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