Scaling ADC Result to a Set Range

[RossWaddell]

I switched to using the EUSART DEFINEs & register settings (commenting out the original ones) and it seems better (no initial wonky characters) but the 2nd line still isn't going to the 2nd line. Maybe if I split out the instruction for the 2nd line with a 5 ms pause?

Here's the data sheet for my serial LCD.

[Archangel]

From Data sheet
Smart Linefeed (control-J, ASCII 10)
Move cursor down one line. If immediately preceded by carriage return, linefeed is ignored

Try it without the 13, see what happens. Or try it with only 13 (more likely)
Failing that, if your message never changes, add spaces between " and MOTOR

[richard]

none of these are correct

#IFDEF USE_LCD_FOR_DEBUG
LCD_INST CON 254 ' instruction
LCD_CLR CON 1 ' Clear screen
LCD_L1 CON 128 ' LCD line 1
LCD_L2 CON 192 ' LCD line 2
#ENDIF

LCD_CLR CON 12 ' Clear screen
LCD_HOME CON 1 ' HOME
LCD_NEXT_LINE CON 13 ' CR does this go back to line 1 when current line is line2 ? seems it will go to first pos of line

LINE 2
WOULD BE HSEROUT [16,80] to be sure


TRY
HSEROUT [1,"ADCInVal=", DEC ADCInVal, " ", 13, "MotorDuty=", DEC MotorDuty, " "]
or
HSEROUT [1,"ADCInVal=", DEC ADCInVal, " ", 16,80, "MotorDuty=", DEC MotorDuty, " "]


ps the display needs 1000ms delay to power on/boot before you try to write to it

[RossWaddell]

none of these are correct



LCD_CLR CON 12 ' Clear screen
LCD_HOME CON 1 ' HOME
LCD_NEXT_LINE CON 13 ' CR does this go back to line 1 when current line is line2 ? seems it will go to first pos of line

LINE 2
WOULD BE HSEROUT [16,80] to be sure


TRY
HSEROUT [1,"ADCInVal=", DEC ADCInVal, " ", 13, "MotorDuty=", DEC MotorDuty, " "]
or
HSEROUT [1,"ADCInVal=", DEC ADCInVal, " ", 16,80, "MotorDuty=", DEC MotorDuty, " "]


ps the display needs 1000ms delay to power on/boot before you try to write to it

What makes you think they're not correct? The clear screen command has worked just fine all along. Nonetheless, I will try what you suggest.

[richard]

from your data sheet link

Clear Screen (control-L, ASCII 12)
Clear the screen.

you did read it ?

[RossWaddell]

Thanks to all your help, the screen is finally working. In case anyone is interested, here's the working code:

#DEFINE USE_LCD_FOR_DEBUG   ; comment out for non-debug use
   
' ***************************************************************
' Pin Connections
' ***************************************************************

' Vdd      -> pin 1         -> +5V   
' RC5/Rx   -> pin 5         -> EUSART receive
' RC4/Tx   -> pin 6         -> EUSART transmit (LCD)
' RC2      -> pin 8         -> Port motor direction signal (motor 2)
' RC1/CCP4 -> pin 9         -> Port motor PWM output (motor 2)
' RC0      -> pin 10        -> Stbd motor direction signal (motor 1)
' RA2/CCP3 -> pin 11        -> Stbd motor PWM output (motor 1)
' RA1      -> pin 12        -> trim pot input
' Vss      -> pin 14        -> GND
   
DEFINE OSC 16               ; Set oscillator 16Mhz

' USART Settings for Tx/Rc (e.g. LCD)
' > use Mister E PIC Multi-Calc application to get register/DEFINE settings
' > as the values are dependent on the OSC and baud rate

DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive
DEFINE HSER_TXSTA 24h ' Enable transmit, BRGH = 1
DEFINE HSER_CLROERR 1 ' Clear overflow automatically
DEFINE HSER_SPBRG 130 ' 2400 Baud @ 16MHz, 0.0%
                               
' ***************************************************************
' Device Fuses
' ***************************************************************

#CONFIG
   __config _CONFIG1, _FOSC_INTOSC & _WDTE_ON & _PWRTE_ON & _MCLRE_OFF & _CP_OFF & _CPD_OFF
   __config _CONFIG2, _PLLEN_OFF & _STVREN_ON & _BORV_LO & _LVP_OFF
#ENDCONFIG

' ***************************************************************
' Initialization
' ***************************************************************

OSCCON    = %01111000       ; 16MHz internal osc

pause 100

APFCON0.2 = 0               ; Tx on RC4 for LCD display
APFCON0.7 = 0               ; Rx on RC5

BAUDCON.4 = 1               ; Transmit inverted data to the Tx pin

' From Mister E's Multi-Calc for EUSART:
SPBRGH    = 6
BAUDCON.3 = 1               ' Enable 16 bit baudrate generator

ANSELC    = 0               ; Digital only for all PortC pins
TRISC     = 0               ; Make all PORTC pins output

TRISA     = %00000010	    ; Make all pins output except for RA1
                            ; (trim pot input)
ANSELA    = %00000010       ; Analog on PORTA.1 (AN1) only

FVRCON    = 0               ; Fixed Voltage Reference is disabled
ADCON0    = %00000101       ; ADC enabled on AN1 (RA1) only; ADC conversion
                            ; enabled
PAUSEUS 20                  ; wait for the analog switch 'glitch' to die down
ADCON1    = %00110000       ; Left-justified results in 8-bits; Frc as timer
 
#IFDEF USE_LCD_FOR_DEBUG
'   Display control codes for PC1602LRU-XWA serial LCD
'   (see 'Dropbox\PBP Projects\PIC Datasheets\PC1602LRU-XWA LCD Datasheet.pdf' 
'   for list of control codes)
    LCD_HOME      CON 1     ' Cursor home
    LCD_CLR       CON 12    ' Clear screen
    LCD_HIDE_CRSR CON 4     ' Hide cursor
    LCD_NEXT_LINE CON 13    ' Move cursor to the first position of the next line 
#ENDIF

MotorDuty   VAR BYTE        ; Actual duty cycle for motor
ADCInVal    VAR BYTE        ; stores ADCIN result read from trim pot
compVal     VAR BYTE        ; stores last-changed ADC value
MinDuty     CON 100         ; Minimum speed to rotate motor for this application
MaxDuty     CON 252        
MaxADCVal   CON 255         ; 255 for 8-bit; 1023 for 10-bit

#IFDEF USE_LCD_FOR_DEBUG
    pause 1000
    HSEROUT [LCD_CLR]
    pause 5
    HSEROUT ["LCD Init",LCD_NEXT_LINE]
    pause 5
    HSEROUT ["PC1602LRU-XWA"]
    pause 1500
#ENDIF

gosub Do_ADC
compVal = ADCInVal           ; set initial compare value
GOSUB Map_ADC_Val_to_PWM_Duty
                                                              
Main:
    gosub Do_ADC
    pause 100

    If ADCInVal <> compVal Then
        compVal = ADCInVal
        GOSUB Map_ADC_Val_to_PWM_Duty
    endif
 
GOTO Main

Do_ADC:
    PAUSEUS 50              ' Wait for A/D channel acquisition time
    ADCON0.1 = 1            ' Start conversion
    
    WHILE ADCON0.1 = 1      ' Wait for it to complete
    WEND

    ADCInVal = ADRESH

    return


Map_ADC_Val_to_PWM_Duty:
'   Arduino Map function to emulate:
'   ===============================
'   map(value, fromLow, fromHigh, toLow, toHigh)

'   long map(long x, long in_min, long in_max, long out_min, long out_max)
'   {
'     return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
'   }

    MotorDuty = (compVal - 0) * (MaxDuty - MinDuty)/(MaxADCVal - 0) + MinDuty
    
    #IFDEF USE_LCD_FOR_DEBUG
        HSEROUT [LCD_CLR]
        pause 5
        HSEROUT ["compVal=",DEC compVal,"  ",LCD_NEXT_LINE]
        pause 5
        HSEROUT ["MotorDuty=",DEC MotorDuty,"  "]
    #ENDIF

    RETURN