Trevor's Electonics Blog

This fix refers to the library version release 12 April 2011. When using an Explorer 16 board and setting the Macro definition of EXPLORER16_100P in MPLab, parts of the library do not pick it up correctly rendering the heartbeat LED and the UART to not work. No compilor error is noticed.

In the file lib\include\pic24_libconfig.h at line 76, change the following section of code:

/** Select one of the hardware platform above to compile for. */
#ifndef HARDWARE_PLATFORM
#define HARDWARE_PLATFORM DEFAULT_DESIGN
#endif
// Verify that a valid hardware platform is selectd
#if (HARDWARE_PLATFORM != EXPLORER16_100P)   && \
    (HARDWARE_PLATFORM != DANGEROUS_WEB)     && \
    (HARDWARE_PLATFORM != STARTER_BOARD_28P) && \
    (HARDWARE_PLATFORM != DEFAULT_DESIGN)
#error Invalid hardware platform selected.
#endif
//@}

Replacing the above code with this code:

/** Select one of the hardware platform above to compile for. */
/* The automated method expects the board is defined in MPLAB
   using Use Project->Build Options-> Project, click on
   the MPLAB C30 tab, and in Macro Definitions click 'Add',
   and add:
      - For the Explorer 16 board - EXPLORER16_100P
      - For the Dangerous Prototypes web server - DANGEROUS_WEB
      - For the Microchip 16-bit 28-pin Starter Board - STARTER_BOARD_28P
   If the above is not set, the code will compile with the default
   of DEFAULT_DESIGN
*/
#ifndef HARDWARE_PLATFORM
#ifdef EXPLORER16_100P
#define HARDWARE_PLATFORM EXPLORER16_100P
#elif STARTER_BOARD_28P
#define HARDWARE_PLATFORM STARTER_BOARD_28P
#elif DANGEROUS_WEB
#define HARDWARE_PLATFORM DANGEROUS_WEB
#else
#define HARDWARE_PLATFORM DEFAULT_DESIGN
#endif
#endif
// Verify that a valid hardware platform is selectd
#if (HARDWARE_PLATFORM != EXPLORER16_100P)   && \
    (HARDWARE_PLATFORM != DANGEROUS_WEB)     && \
    (HARDWARE_PLATFORM != STARTER_BOARD_28P) && \
    (HARDWARE_PLATFORM != DEFAULT_DESIGN)
#error Invalid hardware platform selected.
#endif
//@}

This will now pick up the Macro definition set in MPLab and compile the components of the library needed for the Explorer 16 to function.

So far have tested the above with the Explorer 16, PIC24HJ256GP610A PIM, and the reset.c example from chapter 8 in the Microcontrollers: From Assembly Language to C Using the PIC24 Family.

For those that use the Explorer 16 board and have in the last 12 or so months purchased the PIC24HJ256GP610 PIM from Microchip (part number MA240012) may have noticed it’s got a different chip on it. It now uses the PIC24HJ256GP610A which has some issues when using the library included with the book Microcontrollers: From Assembly Language to C Using the PIC24 Family.

This article shows how I modified the library (12 Apr 2011 version) from http://www.ece.msstate.edu/courses/ece3724/main_pic24/labs/files/pic24_code_examples.zip

In lib\common\pic24_configbits.c at about line 261 fine the line that contains

#if defined(EXPLORER16_100P) && defined(__PIC24HJ256GP610__)

and change it to

#if defined(EXPLORER16_100P) && (defined(__PIC24HJ256GP610__) || defined(__PIC24HJ256GP610A__))

In lib\include\pic24_ports.h at about line 700 you will find the following:

00700 #elif defined(__PIC24HJ256GP610__)
00701
00702 #include "devices/pic24hj256gp610_ports.h"

Change line 700 to:

#elif defined((__PIC24HJ256GP610__) || defined(__PIC24HJ256GP610A__))

The above uses the same .h file for the 610A as for the 610 on the assumption the two are pin compatible in every way. I have not yet found they are not, or any other reason to use a seperate ports file for the chip.

In lib\include\pic24_chip.h at aprox line 336 you will find the following little block of code:

#ifdef __PIC24HJ256GP610__
#define DEV_ID 0x00007B
#define DEV_ID_STR "PIC24HJ256GP610"
#endif

#if (defined(__PIC24HJ64GP206__) || defined(__PIC24HJ64GP210__) || defined(__PIC24HJ64GP506__)
|| defined(__PIC24HJ64GP510__)\
|| defined(__PIC24HJ128GP206__) || defined(__PIC24HJ128GP210__) || defined(__PIC24HJ128GP306__)\
|| defined(__PIC24HJ128GP310__) || defined(__PIC24HJ128GP506__)|| defined(__PIC24HJ128GP510__)\
|| defined(__PIC24HJ256GP206__) || defined(__PIC24HJ256GP210__)|| defined(__PIC24HJ256GP610__))

#define EXPECTED_REVISION1 0x003002
#define EXPECTED_REVISION1_STR "A2"
#define EXPECTED_REVISION2 0x003004
#define EXPECTED_REVISION2_STR "A3"
#define EXPECTED_REVISION3 0x003040
#define EXPECTED_REVISION3_STR "A4"
#endif

Replace this block of code above with:

#ifdef __PIC24HJ256GP610__
#define DEV_ID 0x00007B
#define DEV_ID_STR "PIC24HJ256GP610"
#endif

#ifdef __PIC24HJ256GP610A__
#define DEV_ID 0x0000077B
#define DEV_ID_STR "PIC24HJ256GP610A"
#endif

#if (defined(__PIC24HJ64GP206__) || defined(__PIC24HJ64GP210__) || defined(__PIC24HJ64GP506__)\
|| defined(__PIC24HJ64GP510__)\
|| defined(__PIC24HJ128GP206__) || defined(__PIC24HJ128GP210__) || defined(__PIC24HJ128GP306__)\
|| defined(__PIC24HJ128GP310__) || defined(__PIC24HJ128GP506__)|| defined(__PIC24HJ128GP510__)\
|| defined(__PIC24HJ256GP206__) || defined(__PIC24HJ256GP210__)|| defined(__PIC24HJ256GP610__))
#define EXPECTED_REVISION1 0x003002
#define EXPECTED_REVISION1_STR "A2"
#define EXPECTED_REVISION2 0x003004
#define EXPECTED_REVISION2_STR "A3"
#define EXPECTED_REVISION3 0x003040
#define EXPECTED_REVISION3_STR "A4"
#endif

#if defined(__PIC24HJ256GP610A__)
#define EXPECTED_REVISION1 0x003003
#define EXPECTED_REVISION1_STR "A1"
#endif

I’m not sure what the second last line #define EXPECTED_REVISION1_STR “A1″ should be and have not been able to find it, but the above has been tested using the reset.c example from chapter 8 of the book on the Explorer 16 and is working (provided you have also performed the mod described in this article).

This will update the library to accommodate for the new version of the PIC24HJ256GP610 PIM which now uses a PIC24HJ256GP610A.

If your using a different linker file than what comes with the compiler you will need to set the /p option for the linker to specify your processor manually. For some reason v3.38 doesn’t pick this up automatically. If this is not done, the following error message will probably be recieved:

Error – Device not specified. Use /p option to specify a device.

Setting the /p option is simple, click ‘Project – Build Options – Project’, go to the MPLINK Linker tab. Then check the ‘Use Alternate Settings’ check box.

The default string will look like:

/m”$(BINDIR_)$(TARGETBASE).map” /w /o”$(BINDIR_)$(TARGETBASE).cof”

Change this to:

/m”$(BINDIR_)$(TARGETBASE).map” /w /p18F2450  /o”$(BINDIR_)$(TARGETBASE).cof”

using your processor instead of the /p18F2450 in the above example. Note, there is no space between the p and the 1. It’s just the font makes it look like there is.

Well I’m going to run with the PIC24 for the time being and use the Microcontrollers – From Assembly Language to C Using the PIC24 Family book, but jumping to chapter 8 as the assembly language is not what I want at the moment. It’s learning about C and the PIC24. Anyway, as I’m using the Explorer 16 board, I’m going to share the differences in the sample code that should apply. This is the first installment for chapter 8.

My first observation is the author hasn’t identified the file names of the examples in his book and as his book doesn’t include the full text of the samples, it’s a bit of guess work to find them. So I’ll help you along your way. The first example on page 258 is called “ledflash_nomacros” and it’s in the chap8 folder.

One thing you need to do with all the examples when using the Explorer16 board is define the macro EXPLORER16_100P either in the include/pic24_all.h file or it must be added to the MPLAB project (Use Project->Build Options-> Project, click on the MPLAB C30 tab, and in Macro Definitions click ‘Add’, and add EXPLORER16_100P). Where it makes sense, I’m going to use the macro definition to keep the original code in tact while adding specific changes for the Explorer 16 board.

Note: the PIM I’m using is the PIC24FJ128GA010 100pin PIM (Microchip part number MA240011).

So here is the source for main() for this exercise. The rest of the file should remain the same.

void a_delay(void) {
  uint16 u16_i,u16_k;
  // change count values to alter delay
  for (u16_k=1800; --u16_k;) {
    for (u16_i = 1200 ; --u16_i ; );
  }
}
int main(void) {
  configClock();    //clock configuration
  /********** GPIO config **********/

#if defined(EXPLORER16_100P)

// For the explorer 16, we're not going to use the open drain as the LED is
// wired from ground through a current limit resistor direct to pin 91 of
// the PIC24FJ128GA010

  _TRISA6 = 0;         //Config RB15 as output
  _LATA6 = 0;          //RB15 initially low
  while (1) {           //infinite while loop
    a_delay();          //call delay function
    _LATA6 = !_LATA6;  //Toggle LED attached to RB15
  } // end while (1)
#warning using Explorer16 code

#else // not EXPLORER16_100P

#ifdef _ODB15          //PIC24F CPU header files define this instead of ODCB15
  _ODB15 = 1;          //enable open drain
#else
  _ODCB15 = 1;          //enable open drain
#endif
  _TRISB15 = 0;         //Config RB15 as output
  _LATB15 = 0;          //RB15 initially low
  while (1) {           //infinite while loop
    a_delay();          //call delay function
    _LATB15 = !_LATB15;  //Toggle LED attached to RB15
  } // end while (1)
#warning NOT using Explorer16 code

#endif  //#if defined(EXPLORER16_100P)

}

When you open the project file (.mcp) for this exercise you will notice the linker script in the linker scripts section of the files explorer. You need to delete this one. No need to add another one as MPLAB will pick up the right one automatically if you have used the default install.

You will notice in this code segment I’ve added a couple of warning messages for the compiler to see what parts of the code it compiles. You can have them in or take them out. They are there just to make sure the compiler is doing what is expected.

Now if you try and use DEBUG as per the default project, you will see a number of failures and the program wont run. The first will be a pop up message:

• ICDWarn0046:  Because clock switching is enabled, MPLAB ICD 2 requires the user to cycle target power after a program operation.

And then a message in the output window:

• ICD0083: Debug:  Unable to enter debug mode.  Please double click this message for more information.

I chose to ignore and change to a RELEASE build to see it working. Do this by following these steps:

1. Change the DEBUG drop down to RELEASE
2. Select a programmer (Programmer – Select Programmer). I’m using the MPLAB ICD2 so the rest talks about what happens with the ICD2.
3. Rebuild all (Ctrl+F10)
4. When you get the BUILD SUCCEEDED message, program the device (Programmer – Program). You will get the ICDWarn0046 message, just click OK.
5. When you get the “MPLAB ICD 2 ready for next operation”, disconnect the ICD2 and watch your program run. The LED second from left will flash at about once per second.