Help with other switching to other types of pic controllers

[brad]

Unfortunately I have not used that pic in MPLAB. Have you downloaded the data sheet for your PIC? Did you also incorporate the correct include file?

[bitfogav]

I am trying to learn ASM but using a different pic instead of the 16F684a.
I have a developement board (TAP-28) with an 18F2420. I have looked all over the data sheet for the config settings but?? maybe looking for the wrong thing. Right Church, Wrong Pew.
I am starting out with the LED flasher that I downloaded for tutorial 2.

Using ASM and mplab for 18F devices is not an easy task!.. But theres two ways of setting the Config bits in MPLAB.

Firstly you need to set the device under the "Configure" tab.

Then you can set the Config settings in code or using the Configuration Bits under the "Configure" tab.

If you set them in Code then it should look something like this: (NOTE this is some config settings for a 18F4550)

Code: Select all

        CONFIG  PLLDIV = 5              ; Divide by 5 (20 MHz oscillator input) 
        CONFIG  CPUDIV = OSC1_PLL2      ; [OSC1/OSC2 Src: /1][96 MHz PLL Src: /2] 
        CONFIG  USBDIV = 2              ; USB from the 96 MHz PLL divided by 2 
        CONFIG  FOSC = HSPLL_HS         ; HS oscillator, PLL enabled, HS used by USB 
        CONFIG  FCMEN = OFF             ; Fail-Safe Clock Monitor disabled 
        CONFIG  IESO = OFF              ; Oscillator Switchover mode disabled 
        CONFIG  PWRT = ON               ; PWRT enabled 
        CONFIG  BOR = OFF               ; Brown-out Reset enabled in hardware only 
        CONFIG  BORV = 2                ; Brown-out Voltage medium setting 
        CONFIG  VREGEN = ON             ; USB voltage regulator enabled 
        CONFIG  WDT = OFF               ; HW Disabled - SW Controlled 
        CONFIG  WDTPS = 32768           ; Watch-dog timer set to 256*4ms = 1s 
        CONFIG  MCLRE = OFF             ; MCLR pin enabled; RE3 input pin disabled 
        CONFIG  LPT1OSC = OFF           ; Timer1 configured for higher power operation 
        CONFIG  PBADEN = OFF            ; PORTB<4:0> pins are digital I/O on Reset 
        CONFIG  CCP2MX = ON             ; CCP2 input/output is multiplexed with RB3 
        CONFIG  STVREN = ON            ; Stack full/underflow will not cause Reset 
        CONFIG  LVP = OFF               ; Single-Supply ICSP disabled 
        ; 18F4x5x TQFP only CONFIG  ICPRT = OFF             ; ICPORT disabled 
        CONFIG  XINST = OFF             ; Instruction set extension disabled 
        CONFIG  DEBUG = OFF             ; RB6 and RB7 are general purpose I/O pins 
        CONFIG  CP0 = OFF               ; Block 0 (000800-001FFFh) not code-protected 
        CONFIG  CP1 = OFF               ; Block 1 (002000-003FFFh) not code-protected 
        CONFIG  CP2 = OFF               ; Block 2 (004000-005FFFh) not code-protected 
        CONFIG  CP3 = OFF               ; Block 3 (006000-007FFFh) not code-protected 
        CONFIG  CPB = OFF               ; Boot block (000000-0007FFh) not code-protected 
        CONFIG  CPD = OFF               ; Data EEPROM not code-protected 
        CONFIG  WRT0 = ON              ; Block 0 (000800-001FFFh) not write-protected 
        CONFIG  WRT1 = OFF              ; Block 1 (002000-003FFFh) not write-protected 
        CONFIG  WRT2 = OFF              ; Block 2 (004000-005FFFh) not write-protected 
        CONFIG  WRT3 = OFF              ; Block 3 (006000-007FFFh) not write-protected 
        CONFIG  WRTB = ON               ; Boot block (000000-0007FFh) IS write-protected 
        CONFIG  WRTC = OFF              ; Configuration (300000-3000FFh) not write-protected 
        CONFIG  WRTD = OFF              ; Data EEPROM not write-protected 
        CONFIG  EBTR0 = OFF             ; Block 0 not protected from table reads 
        CONFIG  EBTR1 = OFF             ; Block 1 not protected from table reads 
        CONFIG  EBTR2 = OFF             ; Block 2 not protected from table reads 
        CONFIG  EBTR3 = OFF             ; Block 3 not protected from table reads 
        CONFIG  EBTRB = OFF             ; Boot block protected from table reads 

You may find this pdf file useful for setting 18F config settings, but personally I avoid using ASM for 18F and keep that to Swordfish.

PIC18 Configuration settings 51537a.zip

(812.33 KiB) Downloaded 743 times

[MrDEB]

Now I see why you don't use ASM in MPLAB for 18F pics'
I do have a 16F84a on hand I purchased for ?? but its an 18pin device so on to bread-boarding instead of using the Tap28.
This should get me going as in the end I just want to control a tri color LED to simulate a candle flicker. I have a SWORDFISH code that uses a random number generator that I pieced together from several different code examples.

Code: Select all

{
*****************************************************************************
*  Name    : UNTITLED.BAS                                                   *
*  Author  : Doug Bezaire                                                   *
*  Notice  : Copyright (c) 2010 [select VIEW...EDITOR OPTIONS]              *
*          : All Rights Reserved                                            *
*  Date    : 3/26/2010                                                      *
*  Version : 1.0                                                            *
*  Notes   :                                                                *
*          :                                                                *
*****************************************************************************
}
Device = 18F2420
Clock = 8

Include "InternalOscillator.bas" 
Include "RandGen.bas"
Include "Utils.bas" 
Dim TMR2IE As PIE1.1,         // TMR2 interrupt enable
    TMR2IF As PIR1.1,         // TMR2 overflow flag
    TMR2ON As T2CON.2,        // Enables TMR2 to begin incrementing
    Signal_Pin As PORTB.0     // Signal output to frequency meter
 
Dim Red_Pin As PORTA.0,        //was b.0
    Green_Pin As PORTA.1,       //was b1
    Blue_Pin As PORTA.2,        //was b2
    Red_Duty As Byte,
    Green_Duty As Byte,
    Blue_Duty As Byte,
    Red_DutyVal As Byte,
    Green_DutyVal As Byte,
    Blue_DutyVal As Byte,
    RandomVal As Byte
   
 
Dim uS As Word,
    mS As Word           
   // ranval(1)as word
Interrupt TMR2_Interrupt()
    High(Signal_Pin)
    Save(0)                   // Back up system variables   
    If TMR2IF = 1 Then        // Check if the interrupt was from TMR2   
        TMR2IF = 0            // Clear the TMR2 interrupt flag
        uS = uS + 50
        If uS >= 1000 Then
            uS = uS - 1000
            Inc(mS)
        EndIf       
        Inc(Red_DutyVal)
        Inc(Green_DutyVal)
        Inc(Blue_DutyVal)
        If Red_DutyVal > Red_Duty Or Red_Duty = 0 Then
            Red_Pin = 0
        Else
            Red_Pin = 1
        EndIf
        If Green_DutyVal > Green_Duty Or Green_Duty = 0 Then
            Green_Pin = 0
        Else
            Green_Pin = 1
        EndIf
        If Blue_DutyVal > Blue_Duty Or Blue_Duty = 0 Then
            Blue_Pin = 0
        Else
            Blue_Pin = 1
        EndIf               
    EndIf                     //
    Restore                   // Restore system variables
    Low(Signal_Pin)
End Interrupt
 
Private Sub TMR2_Initialize()
    TMR2ON = 0                // Disable TMR2
    TMR2IE = 0                // Turn off TMR2 interrupts   
 
    PR2 = 149                 // TMR2 Period register PR2
    T2CON = %00000001         // T2CON 0:1 = Prescale
                              //        00 = Prescale is 1:1
                              //        01 = Prescale is 1:4
                              //        1x = Prescale is 1:16                                 
                              //      3:6 = Postscale              
                              //     0000 = 1:1 postscale
                              //     0001 = 1:2 postscale
                              //     0010 = 1:3 postscale...
                              //     1111 = 1:16 postscale
 
    TMR2 = 0                  // Reset TMR2 Value   
    TMR2IE = 1                // Enable TMR2 interrupts
    TMR2ON = 1                // Enable TMR2 to increment
    Enable(TMR2_Interrupt)
End Sub
 
// Start Of Program...
Low(Red_Pin)
Low(Green_Pin)
Low(Blue_Pin)
Red_Duty = 30
Green_Duty = 10
Blue_Duty = 5
Red_DutyVal = 0
Green_DutyVal = 0
Blue_DutyVal =0
 
uS = 0
mS = 0

RandGen.Initialize(128)       // Initialize the Random Number generator
TMR2_Initialize               // Setup and enable TMR2
 
While True                    // Create an infinite loop
    RandomVal = RandGen.Rand  // Grab a random number from 0 to 255 
    // Select RandomVal         // Find out what colour to increase/decrease
        //Case 0 To 42
             Red_Duty =RandomVal-5 
                //mS = 0
             // (Red_Duty)=Rand(1)
               // Repeat
               // Until mS = 19
               // and Red_Duty>0
           // endif
           
            
        //Case 43 To 84
            If Red_Duty > 0
              Then  mS = 0
                Repeat
                Until mS = 19
                Dec(Red_Duty)
            EndIf
       // Case 84 To 127
             Green_Duty =RandomVal-20 
              //Then  mS = 0
              //  Repeat
              //  Until mS = 19
              //  Inc(Green_Duty)
           // EndIf
       // Case 128 To 170
            If Green_Duty > 0
              Then  mS = 0
                Repeat
                Until mS = 19
                Dec(Green_Duty)
            EndIf
      //  Case 170 To 212
             Blue_Duty = RandomVal-30
             // Then  mS = 0
              //  Repeat
              //  Until mS = 19
              //  Inc(Blue_Duty)
           // EndIf
       // Case 212 To 255
            If Blue_Duty > 0
              Then  mS = 0
                Repeat
                Until mS = 19
                Dec(Blue_Duty)
            EndIf
            Wend
          
         End

[brad]

but personally I avoid using ASM for 18F and keep that to Swordfish.

That's a great idea

I am certainly glad that I first learned ASM though because once I then moved onto swordfish basic, I got a very good appreciation for how nice it is to have use a high level language, I have not turned back to ASM.

So I guess what I'm saying is, if I had learned Swordfish first, I may never have had the desire to go and learn ASM!

[rd1196]

I am many years late to this party but if Jumbosize is by any chance still curious I had a similar problem when I tried to use the LED flasher code Brad provided with a 12f615, my problem was in the cblock h'20' directive where you declare the delay constants since in my case the memory locations for the general purpose registers didnt start until h'40' so the LED was constantly on since there were no registers holding the values for the delays.

Hopefully it is not too late...