PBP projects for R/C models

**Kenjones1935** · - 27th January 2010, 22:15

I think I am being told that HPWM can not do the job that I need done. Who has a suggestion?

**ScaleRobotics** · - 27th January 2010, 22:39

Originally Posted by Kenjones1935

I think I am being told that HPWM can not do the job that I need done. Who has a suggestion?

Did you just open the floor to my broken record again?! Here is my view, but I agree, you (we all) need to hear more viewpoints than mine.

Darrel Taylor Interrupts using TMR0 for pulse width, and TMR2 for 20ms period, and receiver pulse width sensing with CCP1_INT and TMR1. Your chip has them, just need to utilize them.

If you always have an RC receiver on, then you can use that as your time base for 20ms. So, you could use the CCP1_INT to read the pulse width coming from the receiver. (This will use TMR1). Then you could use TMR0, or TMR2 for the pulse width. Every time you calculated the pulse from your CCP1_INT, you would send out your servo pulse on whatever pin you like, or control multiple pins, using the same timer.

You really just need to start playing around with these timers and interrupts, and pulse some pins to get your head around it. But without a scope, it will be pretty difficult in my opinion.

Here some scope info that you asked me about. It is a stand alone, but has a USB port and free software that comes with it. It cost just under $300.00. http://picbasic.co.uk/forum/showthread.php?t=12483

**rmteo** · - 27th January 2010, 23:50

Ken,

Can you do a LED blinky without using PAUSE (or any other delay commands)? Try to do a 1 second blinky using a timer. When you can do that, you will be well on your way to solving your motor ESC problem.

**Kenjones1935** · - 28th January 2010, 05:45

Guys and maybe Gals,

I am getting frustrated. I can not find the documentation that I need. I need Assembler Language details for the 16-bit chips. I need 16-bit BASIC libraries (Microchip talks C, not Basic). Darrel Taylor is rebuilding his site. He is not accepting new members.

Microchip has screwed up on this link:

MPLAB Assembler, Linker and Utilities for 16-Bit Devices User's Guide
which points to-->
http://ww1.microchip.com/downloads/e...Doc/51317G.pdf

But when you download51317G you discover it is about the 24-BIt devices. It is the same document that -->

DS51317 - MPLAB Assembler, Linker and Utilities for PIC24 MCUs and dsPIC DSCs User's Guide

points to.

What is the number for the 16-Bit devices user's guide?? I have not found a complete list of Assembly language code, syntax, structure whatever! Without that I do not see how I can understand what this 16F887 is doing.

Also it is late. I am going to bed.

Ken

**mackrackit** · - 28th January 2010, 06:02

Ken,

Darrel's site must have been down for what evere reason. It seems to work now.
http://www.PBPgroup.com/

ASM instuctions are normally in the devices data sheet. But... Please do not take this the wrong way. If you are having trouble with Basic I doubt it ASM will do much good.

I like remto's sugesstion about blinky. Give that a shot.

**rmteo** · - 28th January 2010, 20:34

Originally Posted by mackrackit

Ken,

....ASM instuctions are normally in the devices data sheet. But... Please do not take this the wrong way. If you are having trouble with Basic I doubt it ASM will do much good.

I like remto's sugesstion about blinky. Give that a shot.

Ken, I highly recommend taking Dave's advise. You need a better understanding of what makes a PIC tick (hint, read the free book I linked to). When you have that under your belt, then the coding is the really easy part. It doesn't matter whether you use C, BASIC (PBP or some other variant) or ASM - the situation is the same.

**ScaleRobotics** · - 29th January 2010, 11:40

Here is some code that will measure an RC receiver pulse width coming in on GPIO.2, perform a little math on the value, and put out the wave form out on GPIO.1, using DT Interrupts.

It's on a little 12F683 and was written for 8mhz internal. Looks pretty good on the scope. I need to test it on a motor controller though. But time for bed.....

Code:

<html>
<head></head>
<body><!--StartFragment--><pre><code><font color="#000080"><i>
</i></font><b>DEFINE </b>OSC 8
<b>INCLUDE </b><font color="#FF0000">&quot;DT_INTS-14.bas&quot;</font><font color="#000080"><i>;interrupt routines
</i></font><b>INCLUDE </b><font color="#FF0000">&quot;sub16.inc&quot;     </font><font color="#000080"><i>; subtract 16 bit macro

</i></font><b>DEFINE </b>DEBUG_REG	GPIO
<b>DEFINE </b>DEBUG_BIT	0
<b>DEFINE </b>DEBUGIN_BIT	1

<b>DEFINE </b>DEBUG_BAUD	38400
<b>DEFINE </b>DEBUG_MODE	0

INTCON = %10101000      <font color="#000080"><i>'
</i></font>OSCCON = %01110000      <font color="#000080"><i>'set for 8mhz internal
</i></font>CMCON0 = 7              <font color="#000080"><i>'TURN COMPARITORS OFF
</i></font>ANSEL  = %00000000      <font color="#000080"><i>'Set A/D OFF
</i></font>ADCON0 = %00000000      <font color="#000080"><i>'Analog converter OFF 
</i></font>TRISIO = %010100        <font color="#000080"><i>'Set GSIO 4 and 2 to INPUT, others to OUTPUT
</i></font>OPTION_REG = %11000010
T1CON  = %00110001
T2CON  = %01001110
CCP1CON = %00000101

risetime <b>VAR WORD       </b><font color="#000080"><i>;used for pulse width measure start of pw

</i></font>falltime <b>VAR WORD       </b><font color="#000080"><i>;time at end of pulse width
</i></font>falltime_l <b>VAR </b>falltime.Byte0
falltime_h <b>VAR </b>falltime.Byte1
risetime_l <b>VAR </b>risetime.Byte0
risetime_h <b>VAR </b>risetime.Byte1
pulsewidth <b>VAR WORD
</b>pulsewidth_l <b>VAR </b>pulsewidth.Byte0
pulsewidth_h <b>VAR </b>pulsewidth.Byte1

ServoOut <b>VAR </b>GPIO.1
ServoOut = 0
pulse <b>VAR BYTE

</b>TMR0 = 0
pulse = 255
bittest <b>VAR BIT

ASM
</b><font color="#008000">INT_LIST  macro    </font><font color="#000080"><i>; IntSource,        Label,  Type, ResetFlag?
        </i></font><font color="#008000">INT_Handler   TMR0_INT,   PulseOut,   ASM,  yes
        INT_Handler   TMR2_INT,   period,     ASM,  yes
        INT_Handler   CCP1_INT,   PWMeasure,  ASM,  yes
    endm
    INT_CREATE               </font><font color="#000080"><i>; Creates the interrupt processor

    </i></font><font color="#008000">INT_ENABLE  TMR0_INT     </font><font color="#000080"><i>; Enable pulseout interrupts  
    </i></font><font color="#008000">INT_ENABLE  TMR2_INT     </font><font color="#000080"><i>; enable period interrupt (20ms)
    </i></font><font color="#008000">INT_ENABLE  CCP1_INT     </font><font color="#000080"><i>; enable interrupt to increment pulse width (test)
</i></font><b>ENDASM
    PAUSE </b>200
Main:
    <b>PAUSE </b>20
    <font color="#000080"><i>;debug dec pulsewidth,&quot; &quot;,10,13
    </i></font>pulse = ((pulsewidth * 8)/10)-167 <font color="#000080"><i>;scale to fit into a byte
    </i></font>pulse = 255 - pulse               <font color="#000080"><i>;reverse the stick 
    

</i></font><b>GOTO </b>Main

<font color="#000080"><i>'---[TMR0_INT - interrupt handler]------------------------------------------

</i></font><b>ASM
</b><font color="#008000">PulseOut
    btfsc _bittest      </font><font color="#000080"><i>;test status of bittest bit
    </i></font><font color="#008000">goto $+7            </font><font color="#000080"><i>;if high skip 7 lines
    </i></font><font color="#008000">bcf INTCON,5        </font><font color="#000080"><i>;stop timer
    </i></font><font color="#008000">movf _pulse,w       </font><font color="#000080"><i>;load TMR0 with value of pulse variable
    </i></font><font color="#008000">movwf TMR0
    bsf _bittest        </font><font color="#000080"><i>;set bittest bit, indicating we are on second half
    </i></font><font color="#008000">bsf INTCON,5        </font><font color="#000080"><i>;start timer again for second interrupt
    </i></font><font color="#008000">goto $+3            </font><font color="#000080"><i>;skip to return from interrupt
    </i></font><font color="#008000">bcf INTCON,5        </font><font color="#000080"><i>;stop timer
    </i></font><font color="#008000">bcf _ServoOut       </font><font color="#000080"><i>;bring ServoOut pin low for end of pulse width
    </i></font><font color="#008000">INT_RETURN



</font><b>ENDASM
</b><font color="#000080"><i>'---[TMR2_INT - interrupt handler]------------------------------------------
</i></font><b>ASM
</b><font color="#008000">period
    movlw d'72'          </font><font color="#000080"><i>;fine tune timer2 period
    </i></font><font color="#008000">movwf TMR2    
    bcf INTCON,2         </font><font color="#000080"><i>;clear timer flag if set
    </i></font><font color="#008000">movlw d'17'          </font><font color="#000080"><i>;set timer0 first 1ms time base
    </i></font><font color="#008000">movwf TMR0    
    bsf INTCON,5         </font><font color="#000080"><i>;enable timer0 interrupt 
    </i></font><font color="#008000">bsf _ServoOut        </font><font color="#000080"><i>;set ServoOut pin high (begin pulse width)
    </i></font><font color="#008000">bcf _bittest
    INT_RETURN
</font><b>ENDASM
</b><font color="#000080"><i>'---[CCP1_INT - interrupt handler]------------------------------------------
</i></font><b>ASM

</b><font color="#008000">PWMeasure

    BTFSS   CCP1CON, CCP1M0 </font><font color="#000080"><i>; Check for falling edge watch
    </i></font><font color="#008000">GOTO    FALL_EDGE       </font><font color="#000080"><i>; Go pick up the falling edge
    </i></font><font color="#008000">MOVF    CCPR1L,W        </font><font color="#000080"><i>; else store leading edge value
    </i></font><font color="#008000">MOVWF   _risetime_l         </font><font color="#000080"><i>; into 16 bit word risetime
    </i></font><font color="#008000">MOVF    CCPR1H,W
    MOVWF   _risetime_h
    BCF     CCP1CON, CCP1M0 </font><font color="#000080"><i>; Now capture the trailing edge
    </i></font><font color="#008000">GOTO    ISR_2           </font><font color="#000080"><i>; Exit the interrupt service routine
        
</i></font><font color="#008000">FALL_EDGE:
    BSF     CCP1CON, CCP1M0 </font><font color="#000080"><i>; Re-set for trailing edge capture
    </i></font><font color="#008000">MOVF    CCPR1L,W        </font><font color="#000080"><i>; Store the captured value into
    </i></font><font color="#008000">MOVWF   _falltime_l         </font><font color="#000080"><i>; falltime_l and ...
    </i></font><font color="#008000">MOVF    CCPR1H,W
    MOVWF   _falltime_h       </font><font color="#000080"><i>;             ... falltime_h
    ;
    ; 16 bit subtract 
    ;     falltime = falltime - risetime
    ;
    </i></font><font color="#008000">SUB16   _falltime, _risetime   </font><font color="#000080"><i>;do 16 bit subtraction to find width
    </i></font><font color="#008000">movf _falltime_l,w
    movwf _pulsewidth_l
    movf _falltime_h,w
    movwf _pulsewidth_h
ISR_2
    INT_RETURN


</font><b>ENDASM


</b></code></pre><!--EndFragment--></body>
</html>

**rmteo** · - 28th January 2010, 06:14

Firstly, your PIC16F887 is a 14-bit core device and the ASM manual is here MPASM™ Assembler, MPLINK™ Object
Linker MPLIB™ Object Librarian User’s Guide

Next thing you really need to download is the data sheet PIC16F887

Also, download this FREE book and read it to understand how a PIC works PIC Microcontrollers

The last one is the most useful - I pointed this out to you in an earlier post.

**mackrackit** · - 28th January 2010, 09:02

Ken,
I do not know anything about RC stuff, but here is something to play with.

Code:

<font color="#000080"><i>'16F887 INT RUPT
'44 PIN DEMO BOARD
   </i></font>@ <font color="#0000FF"><b>__config _CONFIG1</b></font>, <font color="#0000FF"><b>_INTRC_OSC_NOCLKOUT </b></font>&amp; <font color="#0000FF"><b>_WDT_ON </b></font>&amp; <font color="#0000FF"><b>_MCLRE_OFF </b></font>&amp; <font color="#0000FF"><b>_LVP_OFF </b></font>&amp; <font color="#0000FF"><b>_CP_OFF
   INTCON</b></font>.<font color="#800000"><b>5 </b></font>= <font color="#800000"><b>1    </b></font><font color="#000080"><i>'ENABLE TMR0  DATA SHEET SECTION 14.3.2
   </i></font><font color="#0000FF"><b>OSCCON </b></font>= <font color="#800000"><b>%01110000 </b></font><font color="#000080"><i>'8 Mhz
   </i></font><font color="#0000FF"><b>OPTION_REG </b></font>= <font color="#800000"><b>%10000111  </b></font><font color="#000080"><i>' 1:256 PRESCALE
   </i></font><font color="#FF0000"><b>ON INTERRUPT GOTO </b></font><font color="#0000FF"><b>TLOOP
   CNT  </b></font><font color="#FF0000"><b>VAR BYTE
   </b></font><font color="#0000FF"><b>D    </b></font><font color="#FF0000"><b>VAR BYTE
   </b></font><font color="#0000FF"><b>D </b></font>= <font color="#800000"><b>0
   
   </b></font><font color="#0000FF"><b>START</b></font>:
   <font color="#FF0000"><b>FOR </b></font><font color="#0000FF"><b>CNT </b></font>= <font color="#800000"><b>0 </b></font><font color="#FF0000"><b>TO </b></font><font color="#800000"><b>150
   </b></font><font color="#FF0000"><b>PWM </b></font><font color="#0000FF"><b>PORTD</b></font>.<font color="#800000"><b>7</b></font>,<font color="#0000FF"><b>D</b></font>,<font color="#800000"><b>100
   </b></font><font color="#0000FF"><b>D </b></font>= <font color="#0000FF"><b>D </b></font>+ <font color="#800000"><b>2
   </b></font><font color="#FF0000"><b>NEXT </b></font><font color="#0000FF"><b>CNT
   </b></font><font color="#FF0000"><b>GOTO </b></font><font color="#0000FF"><b>START
   
   </b></font><font color="#FF0000"><b>DISABLE
   </b></font><font color="#0000FF"><b>TLOOP</b></font>:
   <font color="#0000FF"><b>INTCON</b></font>.<font color="#800000"><b>2</b></font>=<font color="#800000"><b>0 </b></font><font color="#000080"><i>' DATA SHEET SECTION 14.3.2
   </i></font><font color="#FF0000"><b>TOGGLE </b></font><font color="#0000FF"><b>PORTD</b></font>.<font color="#800000"><b>4
   </b></font><font color="#FF0000"><b>RESUME
   ENABLE
</b></font>

**mackrackit** · - 28th January 2010, 09:39

http://www.picbasic.co.uk/forum/showthread.php?t=222
Might also help??

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