Fritzing and chipKIT

Digilent using Fritzing to show a button and LED circuit with chipKIT Uno32
Using Fritzing to show a button and LED circuit with chipKIT Uno32

Fritzing! Some of you may have heard of it, some of you might not have, but maybe you’ve seen images like the above. Whether you know about Fritzing or not, you might want to check out Digilent’s blogpost because you might learn something new about Fritzing and chipKIT that you didn’t already know.

Having said that, you might also want to check out Fritzing’s website, where some of the chipKIT boards have already been added and tagged with ‘chipKIT’ in the Projects section. Since Fritzing is all about open-source hardware, you could download any one of the available chipKIT boards and add it to “My Parts” in the Fritzing app, then do with it as your little heart desires.

Happy Fritzing!

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Programming Microchip starter kits from MPIDE

Running on Microchip Starter Kits

MPIDE has been expanded explicitly to support all of the Microchip starter kits such as:
  • PIC32 Starter Kit
  • PIC32 USB Starter Kit
  • PIC32 Ethernet Starter Kit
  • Explorer 16 Starter Kit
Currently for all of these boards you will need some sort of USB to serial adapter. For all but the Exp-16 I use an FTDI cable that breaks out to pins. I connect those to pins on the expansion board for uart1. The PIC32 USB Starter Kit and PIC32 Ethernet Starter Kits are also compatible with the USB PIC32 bootloader. The Explorer-16 has an on-board DB-9 RS-232 connector. This is connected to UART2. The bootloader is configured to use UART2 for the Explorer-16 and the Serial ports for Arduino are remapped so that Serial.print goes to uart2 and Serial1.print goes to uart1. This is all done automatically so the user does not have to worry about it at all. In order to install the bootloader on any of these boards, you have to have one of the Microchip compatible programmers such as the MPLAB ICD 3 or PICkit 3. Ideally you should download MPLAB X IDE from microchip (http://www.microchip.com/mplabx) and use that to compile and burn the bootloader. The bootloader source and pre-compiled hex files are all on github. (https://github.com/chipKIT32/pic32-Arduino-Bootloader)

Using other PIC32 boards

As far as using MPIDE with other boards, the answer is YES, it should work with ANY PIC32 there is. The only limit might be it won’t work on chips smaller than 32K, And that’s because it hasn’t been tried on anything smaller. To get it to work on other boards, a few things have be be done.
  • First, the bootloader has to be burned onto the target board. The source is on github and MPLAB is used to compile and burn the bootloader. The multi-platform MPLAB-X was used on a Mac, but other versions should work as well.
  • If you using a chip that has not already been added to avrdude.conf, that has to be done.
  • You need to add a new entry to boards.txt and then you will be able to program the board directly from MPIDE.
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Header Files

Header files listed in alphabetical order. Files are denoted as either (AVR) or (PIC32) specific, if they apply to both platforms they are marked as (AVR|PIC32). For headers that are marked (AVR|PIC32) they can be either “generic” or “ported”. Generic files will work on either platform without modification where ported files are different for AVR or PIC32.

avr/interrupt.h (AVR)

avr/io.h (AVR)

avr/progmem.h (AVR)

avr/pgmspace.h (AVR)

Tools to access program space of the AVR processor, not needed on PIC32, but some macros can be used in its place to make AVR code run on a PIC32. <source>
  1. if defined(__PIC32MX__)
   // neither PROGMEM or PSTR are needed for PIC32, just define them as null
   #define PROGMEM
   #define PSTR(s) (s)
 
   #define pgm_read_byte(x)	        (*((char *)x))
   #define pgm_read_byte_near(x)	(*((char *)x))
   #define pgm_read_byte_far(x)	(*((char *)x))
   #define pgm_read_word(x)    	(*((short *)x))
   #define pgm_read_word_near(x)	(*((short *)x))
   #define pgm_read_workd_far(x)	(*((short *)x))

   #define	prog_void	 const void
   #define	prog_char	 const char
   #define	prog_uchar	 const unsigned char
   #define	prog_int8_t	 const int8_t
   #define	prog_uint8_t	const uint8_t
   #define	prog_int16_t	const int16_t
   #define	prog_uint16_t	const uint16_t
   #define	prog_int32_t	const int32_t
   #define	prog_uint32_t	const uint32_t
   #define	prog_int64_t	const int64_t
   #define	prog_uint64_t	const uint64_t
  1. else
  2. include <avr/pgmspace.h>
  3. endif
</source>

coffee.h

The start of all good programming sessions.

cpudefs.h

Ethernet/Ethernet.h

Ethernet/Client.h

i2cmaster.h

plib.h (PIC32)

Contains type definitions for PIC32 registers.

SdFat.h

Servo.h (?)

SPI.h (AVR|PIC32) ported

Library to provide SPI communications.

stdint.h (AVR|PIC32) ported

stdio.h

wire.h (?)

wiring.h (?)

WProgram.h (?)

 
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About PIC32 Interrupt Vectors

This is a dump of the interrupt vector from the Max32 (32MX795F512L) It gives you an idea what is available and what is already in use.
Arduino-32MX795F512L>V show interrupt Vectors
FLASH_PROG_BASE=9D000000
EBASE          =9D000000
IntCtl         =00000020
VectorSpacing  =00000001
+++ 0= 02 00---0B4017F0 jump 9D005FC0  _CORE_TIMER_VECTOR
+++ 1= 00 00---FFFFFFFF unused         _CORE_SOFTWARE_0_VECTOR
+++ 2= 00 00---FFFFFFFF unused         _CORE_SOFTWARE_1_VECTOR
+++ 3= 00 00---FFFFFFFF unused         _EXTERNAL_0_VECTOR
+++ 4= 00 00---0B401E5A jump 9D007968  _TIMER_1_VECTOR
+++ 5= 00 00---FFFFFFFF unused         _INPUT_CAPTURE_1_VECTOR
+++ 6= 00 00---FFFFFFFF unused         _OUTPUT_COMPARE_1_VECTOR
+++ 7= 00 00---FFFFFFFF unused         _EXTERNAL_1_VECTOR
+++ 8= 00 00---FFFFFFFF unused         _TIMER_2_VECTOR
+++ 9= 00 00---FFFFFFFF unused         _INPUT_CAPTURE_2_VECTOR
+++10= 00 00---FFFFFFFF unused         _OUTPUT_COMPARE_2_VECTOR
+++11= 00 00---FFFFFFFF unused         _EXTERNAL_2_VECTOR
+++12= 00 00---FFFFFFFF unused         _TIMER_3_VECTOR
+++13= 00 00---FFFFFFFF unused         _INPUT_CAPTURE_3_VECTOR
+++14= 00 00---FFFFFFFF unused         _OUTPUT_COMPARE_3_VECTOR
+++15= 00 00---FFFFFFFF unused         _EXTERNAL_3_VECTOR
+++16= 00 00---FFFFFFFF unused         _TIMER_4_VECTOR
+++17= 00 00---FFFFFFFF unused         _INPUT_CAPTURE_4_VECTOR
+++18= 00 00---FFFFFFFF unused         _OUTPUT_COMPARE_4_VECTOR
+++19= 00 00---FFFFFFFF unused         _EXTERNAL_4_VECTOR
+++20= 00 00---FFFFFFFF unused         _TIMER_5_VECTOR
+++21= 00 00---FFFFFFFF unused         _INPUT_CAPTURE_5_VECTOR
+++22= 00 00---FFFFFFFF unused         _OUTPUT_COMPARE_5_VECTOR
+++23= 00 00---FFFFFFFF unused         _SPI_1_VECTOR
+++24= 00 00---0B401B67 jump 9D006D9C  _I2C_3_VECTOR _UART_1A_VECTOR _UART_1_VECTOR _SPI_1A_VECTOR _I2C_1A_VECTOR _SPI_3_VECTOR
+++25= 01 00---FFFFFFFF unused         _I2C_1_VECTOR
+++26= 00 00---FFFFFFFF unused         _CHANGE_NOTICE_VECTOR
+++27= 01 00---FFFFFFFF unused         _ADC_VECTOR
+++28= 00 00---FFFFFFFF unused         _PMP_VECTOR
+++29= 00 00---FFFFFFFF unused         _COMPARATOR_1_VECTOR
+++30= 00 00---FFFFFFFF unused         _COMPARATOR_2_VECTOR
+++31= 00 00---0B401BDD jump 9D006F74  _UART_2A_VECTOR _I2C_2A_VECTOR _SPI_2_VECTOR _SPI_2A_VECTOR _I2C_4_VECTOR _UART_3_VECTOR
+++32= 00 00---0B401C53 jump 9D00714C  _UART_2_VECTOR _SPI_3A_VECTOR _I2C_3A_VECTOR _UART_3A_VECTOR _SPI_4_VECTOR _I2C_5_VECTOR
+++33= 00 00---FFFFFFFF unused         _I2C_2_VECTOR
+++34= 00 00---FFFFFFFF unused         _FAIL_SAFE_MONITOR_VECTOR
+++35= 01 00---FFFFFFFF unused         _RTCC_VECTOR
===36= 00 00---FFFFFFFF unused         _DMA_0_VECTOR
===37= 00 00---FFFFFFFF unused         _DMA_1_VECTOR
===38= 00 00---FFFFFFFF unused         _DMA_2_VECTOR
===39= 00 00---FFFFFFFF unused         _DMA_3_VECTOR
===40= 00 00---FFFFFFFF unused         _DMA_4_VECTOR
===41= 00 00---FFFFFFFF unused         _DMA_5_VECTOR
===42= 00 00---FFFFFFFF unused         _DMA_6_VECTOR
===43= 00 00---FFFFFFFF unused         _DMA_7_VECTOR
===44= 00 00---FFFFFFFF unused         _FCE_VECTOR
===45= 00 00---FFFFFFFF unused         _USB_1_VECTOR
===46= 00 00---FFFFFFFF unused         _CAN_1_VECTOR
===47= 00 00---FFFFFFFF unused         _CAN_2_VECTOR
===48= 00 00---FFFFFFFF unused         _ETH_VECTOR
===49= 00 00---0B401BA2 jump 9D006E88  _UART_4_VECTOR _UART_1B_VECTOR
===50= 00 00---0B401C18 jump 9D007060  _UART_6_VECTOR _UART_2B_VECTOR
===51= 00 00---0B401C8E jump 9D007238  _UART_5_VECTOR _UART_3B_VECTOR
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The MPIDE Compiler for PIC32

Note: Information in this post applies to MPIDE, which has been deprecated. The recommended IDE for chipKIT core is now Arduino IDE or UECIDE. MPIDE still offers support for legacy code. For more information about MPIDE, please visit the legacy Install Page.

This is a fork of the compiler from about October 2010. So it’s ahead of the Microchip MPLAB C32 v1.12 release, but behind the upcoming C32 v2.00 release. Basically it’s similar to C32 v1.12, but updated to GCC 4.5.1. Also, the default linker scripts are modified to work with the chipKIT bootloader. There are no optimization restrictions in this build, but it will likely be updated less often than the official MPLAB C32 compiler.

Source code: https://github.com/chipKIT32/chipKIT-cxx

MPIDE Compiler optimisation

Currently, MPIDE is configured to call the compiler with the -O2 optimization option. The -O2 set of optimization usually results in a nice balance between code size and speed. However, there are some instances where you want to sacrifice code size (use more FLASH memory) in order to get more speed. Luckily, Rick has introduced features in MPIDE that makes changing the default compiler options easy to change.

To change the optimization level:

1. Open the /hardware/pic32/platforms.txt file in your favorite text editor.
2. Find the lines beginning with pic32.compiler.c.flags and pic32.compiler.cpp.flags. 
   In those lines, you should see a compiler optimization option, -O0, -O1, -O2, -Os, or -O3.
3. Change the optimization level option to the desired level, as listed below.
4. Save platforms.txt
5. Restart MPIDE.
Optimization levels
-O0 - Disable optimizations
-O1 - Reduce code size and execution time, without performing any optimizations that take a 
      great deal of compilation time.
-O2 - Optimize even more. GCC performs nearly all supported optimizations that do not involve a 
      space-speed trade-off. As compared to -O1, this option increases both compilation time and 
      the performance of the generated code. (This is currently the default.)
-O3 - Optimize yet more. GCC optimizes for maximum performance at the expense of code size.
-Os - Optimize for size. -Os enables all -O2 optimizations that do not typically increase code size.
It also performs further optimizations designed to reduce code size.

For example:

    pic32.compiler.c.flags=-O3::-c::-mno-smart-io::-ffunction-sections::-fdata-sections
    pic32.compiler.cpp.flags=-O3::-c::-mno-smart-io::-ffunction-sections::-fdata-sections
If you really want aggressive performance for your sketch, you could also add the -funroll-loops option. Note that this option almost always increases code size but it may or may not increase performance.

For example:

    pic32.compiler.c.flags=-O3::-funroll-loops::-c::-mno-smart-io::-ffunction-sections::-fdata-sections
    pic32.compiler.cpp.flags=-O3::-funroll-loops::-c::-mno-smart-io::-ffunction-sections::-fdata-sections
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Overview of the Build Process

This post is in response to questions about the build process. Some of you are asking very reasonable questions. However, this stuff is specifically hidden to make the entire system easy for the beginner. If you are a beginner, I would recommend ignoring these details to start with.

Nevertheless, to answer your questions, the build process in MPIDE is the same as it is for the original Arduino system. It compiles all of the files in the core/xxx folder, xxx is specified in boards.txt. Normally there is only one and for PIC32, it’s cores/pic32.

It also will compile files from the 2 libraries folders. The 2 locations for libraries are the main one in pic32/libraries–where officially supported libraries go–and the second optional libraries folder in your sketches folder, where you are supposed to put any libraries that you download from 3rd parties. The reason for the second folder is that if you download a new version of MPIDE (or Arduino), you won’t lose those third-party libraries, as happened in earlier versions of Arduino.

It copies all files from your sketch folder, the library folders to a temp folder. You can follow this entire process by holding down the SHIFT key and clicking on COMPILE (the button on the far left). Similarly you can hold down the shift button when you click UPLOAD and you will see the entire UPLOAD process. ONE IMPORTANT NOTE… HITTING UPLOAD ALSO COMPILES SO YOU DO NOT NEED TO DO BOTH.

The compile process uses gcc from a command line. Done differently in MPIDE was the code to drive the compiler; it was totally re-written and is driven by a file called platforms.txt, which spells out the entire compile and link process. In Arduino, this was hard coded and darn near impossible to change.

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