Flip & Click PIC32MZ

Tags: arch:mips chip:pic32mz vendor:mikroelektronika

The Flip & Clock PIC32MZ development board

The Flip & Clock PIC32MZ development board

Documentation for the port of NuttX to the Mikroe Flip&Click PIC32MZ board. That board features the PIC32MZ2048EFH100 MCU. Thanks to John Legg for contributing the Flip&Click PIC32MZ board!

Buttons and LEDs

There are four LEDs on the top, red side of the board. Only one can be controlled by software:

  • LED L: RB14 (SPI3_SCK)

There are also four LEDs on the back, white side of the board:

  • LED A: RA6

  • LED B: RA7

  • LED C: RE0

  • LED D: RE1

A high output value illuminates the LEDs.

These LEDs are available to the application and are all available to the application unless CONFIG_ARCH_LEDS is defined. In that case, the usage by the board port is defined in include/board.h and src/sam_autoleds.c. The LEDs are used to encode OS-related events as follows:

SYMBOL

MEANING

L

A

B

C

D

LED_STARTED

NuttX has been started

OFF

ON

OFF

OFF

OFF

LED_HEAPALLOCATE

Heap has been allocated

OFF

OFF

ON

OFF

OFF

LED_IRQSENABLED

Interrupts enabled

OFF

OFF

OFF

ON

OFF

LED_STACKCREATED

Idle stack created

OFF

OFF

OFF

OFF

ON

LED_INIRQ

In an interrupt

GLO

N/C

N/C

N/C

N/C

LED_SIGNAL

In a signal handler

GLO

N/C

N/C

N/C

N/C

LED_ASSERTION

An assertion failed

GLO

N/C

N/C

N/C

N/C

LED_PANIC

The system has crashed

2Hz

N/C

N/C

N/C

N/C

LED_IDLE

MCU is is sleep mode

—

—

—

—

—

Thus if LED L is glowing faintly and all other LEDs are off (except LED D which was left on but is no longer controlled by NuttX and so may be in any state), NuttX has successfully booted and is, apparently, running normally and taking interrupts. If any of LEDs A-D are statically set, then NuttX failed to boot and the LED indicates the initialization phase where the failure occurred. If LED L is flashing at approximately 2Hz, then a fatal error has been detected and the system has halted.

Note

After booting, LEDs A-D are no longer used by the system and may be controlled the application.

The Flip&Click PIC32MZ has 2 user push buttons labeled T1 and T2 on the white side of the board:

PIN

LED

Notes

RD10

T1

Sensed low when closed

RD11

T2

Sensed low when closed

The switches have external pull-up resistors. The switches are pulled high (+3.3V) and grounded when pressed.

SSD1306 OLED

Hardware

The HiletGo is a 128x64 OLED that can be driven either via SPI or I2C (SPI is the default and is what is used here). I have mounted the OLED on a proto click board. The OLED is connected as follows:

OLED

ALIAS

DESCRIPTION

PROTO CLICK

GND

Ground

GND

VCC

Power Supply

5V (3-5V)

D0

SCL,CLK,SCK

Clock

SCK

D1

SDA,MOSI

Data

MOSI,SDI

RES

RST,RESET

Reset

RST (GPIO OUTPUT)

DC

AO

Data/Command

INT (GPIO OUTPUT)

CS

Chip Select

CS (GPIO OUTPUT)

Note

This is a write-only display (MOSI only)!

SPI

SPI3 is available on pins D10-D13 of the Arduino Shield connectors where you would expect them. The SPI connector is configured as follows:

Pin

J1

Board Signal

PIC32MZ

D10

8

SPI3_SCK

RB14

D11

7

SPI3_MISO

RB9

D12

6

SPI3_MOSI

RB10

D13

5

SPI3_SS

RB9

SPI1 and SPI2 are also available on the mikroBUS Click connectors (in addition to 5V and GND). The connectivity between connectors A and B and between C and D differs only in the chip select pin:

MikroBUS A:

Pin

Board Signal

PIC32MZ

CS

SPI2_SS1

RA0

SCK

SPI2_SCK

RG6

MISO

SPI2_MISO

RC4

MOSI

SPI2_MOSI

RB5

MikroBUS B:

Pin

Board Signal

PIC32MZ

CS

SPI2_SS0

RE4

SCK

SPI2_SCK

RG6

MISO

SPI2_MISO

RC4

MOSI

SPI2_MOSI

RB5

MikroBUS C:

Pin

Board Signal

PIC32MZ

CS

SPI1_SS0

RD12

SCK

SPI1_SCK

RD1

MISO

SPI1_MISO

RD2

MOSI

SPI1_MOSI

RD3

MikroBUS D:

Pin

Board Signal

PIC32MZ

CS

SPI1_SS1

RD13

SCK

SPI1_SCK

RD1

MISO

SPI1_MISO

RD2

MOSI

SPI1_MOSI

RD3

Serial Console

Todo

I am not sure if the USB VCOM ports are available to the software. That is likely another serial port option

Convenient U[S]ARTs that may be used as the Serial console include:

  1. An Arduino Serial Shield. The RX and TX pins are available on the Arduino connector D0 and D1 pins, respectively. These are connected to UART5, UART5_RX and UART5_TX which are RD14 and RD15, respectively.

2) Mikroe Click Serial Shield. There are four Click bus connectors with serial ports available as follows:

  • Click A: UART4 UART4_RX and UART4_TX which are RG9 and RE3, respectively.

  • Click B: UART3 UART3_RX and UART3_TX which are RF0 and RF1, respectively.

  • Click C: UART1 UART1_RX and UART1_TX which are RC1 and RE5, respectively.

  • Click D: UART2 UART2_RX and UART2_TX which are RC3 and RC2, respectively.

Other serial ports are probably available on the Arduino connector. I will leave that as an exercise for the interested reader.

The outputs from these pins is 3.3V. You will need to connect RS232 transceiver to get the signals to RS-232 levels. The simplest options are an expensive Arduino RS-232 shield or a Mikroe RS-232 Click board.

Warning

I have been unable to get the RS-232 Click to work in the mikroBUS A slot. The PIC32MZ did not receive serial input. It appears that there is an error in the some documentation: Either RG9 is not connected to UART4_RX or the PPS bit definitions are documented incorrectly for UART4.

Switching to UART3 eliminates the problem and the serial console is fully functional. I have not tried the other options of UART1, 2, or 5.

On Board Debug Support

There are several debug options:

  1. Using the Arduino IDE (chipKIT core). This is available on the USB-UART port between the C and D MikroBUS sockets. Usage is described in the Flip&Click User Manual.

    Note

    I don’t think trying to use the Arduino IDE is a good option.

  2. Using the mikroC USB HID bootloader. This is is available on the USB port between the A and B MikroBUS sockets. Usage is described in the Flip&Click User Manual.

    There is a simple application available at Mikroe that will allow you to write .hex files via the USB HID bootloader. However, in order to use the bootloader, you will have to control the memory map so that the downloaded code does not clobber the bootloader code FLASH, data memory, exception vectors, etc.

    Note

    At this point, I have found no documentation describing how to build the code outside of the Mikroe toolchain for use with the Mikroe bootloader.

  3. There is an undocumented and unpopulated PICKit3 connector between the B and C mikroBUS sockets.

  4. There is an undocumented and unpopulated mikroProg connector between the A and D mikroBUS sockets.

    Warning

    Since 3) and 4) are undocumented, this would require some research and would, most likely, clobber the USB HID bootloader (and possibly the Arduino support as well).

Installation

From the mikroProg website https://www.mikroe.com/mikroprog-pic-dspic-pic32 Download:

Install the mikroProg Suite. From things I have read, I gather that you must be Administrator when installing the tool. The instructions say that it will automatically install the drivers. It did not for me.

To install the drivers… You will find several directories under mikroprog-pic-dspic-pic32-drivers/. Select the correct directory and run the .EXE file you find there.

When I started the mikroProg suite, it could not find the USB driver. After a few frustrating hours of struggling with the drivers, I found that if I start the mikroProg suite as a normal user, it does not find the driver. But if I instead start the mikroProg suite as Administrator… There it is! A little awkward but works just fine.

Flashing

Warning

  1. Following these steps will most certainly overwrite the bootloader that was factory installed in FLASH!

  2. Due to the position and orientation of the mikroProg connector you may lose functionality: If you attach mikroProg to the red side of the board, you will not be able to use the Arduino Shield Connector while the mikroProg connected. If you attach mikroProg to the white side of the board, you will similarly lose access to mikroBUS connectors A and D.

    Hindsight is 20/20 and in retrospect I would look for a right handler header to priven the mikroProg connector from interfering with the Arduino connection.

Tool Issues

If using a Jlink, note that only these versions work with PIC32:

  • J-Link BASE / EDU V9 or later

  • J-Link ULTRA+ / PRO V4 or later

This is the command to use:

$ JLinkGDBServer -device PIC32MZ2048EFH100 -if 2-wire-JTAG-PIC32 -speed 12000

Hardware setup

You will need to add a five pin header to the mikroProg connector between the A and D mikroBUS sockets.

Connect the mikroProg to the outer 5 pins of the mikroProg’s 10-pin connector to the 5-pin header, respecting the pin 1 position: The colored wire on the ribbon cable should be on the same side as the tiny arrow on the board indicating pin 1.

Connect the mikroProg to your computer with the provided USB cable; also power the Flip’n’Clip board with another USB cable connected to the computer. Either USB port will provide power.

Creating Compatible NuttX HEX files

Intel Hex Format Files

When NuttX is built it will produce two files in the top-level NuttX directory:

  1. nuttx: This is an ELF file

  2. nuttx.hex: This is an Intel Hex format file. This is controlled by the setting CONFIG_INTELHEX_BINARY in the .config file.

The PICkit tool wants an Intel Hex format file to burn into FLASH. However, there is a problem with the generated nuttx.hex: The tool expects the nuttx.hex file to contain physical addresses. But the nuttx.hex file generated from the top-level make will have address in the KSEG0 and KSEG1 regions.

tools/pic32/mkpichex:

There is a simple tool in the NuttX tools/pic32 directory that can be used to solve both issues with the nuttx.hex file. But, first, you must build the tool:

$ cd tools/pic32
$ make -f Makefile.host

Now you will have an executable file called mkpichex (or mkpichex.exe on Cygwin). This program will take the nutt.hex file as an input, it will convert all of the KSEG0 and KSEG1 addresses to physical address, and it will write the modified file, replacing the original nuttx.hex.

To use this file, you need to do the following things:

$ export PATH=???  # Add the NuttX tools/pic32mx directory to your
                   # PATH variable
$ make             # Build nuttx and nuttx.hex
$ mkpichex $PWD    # Convert addresses in nuttx.hex.  $PWD is the path
                   # to the top-level build directory.  It is the only
                   # required input to mkpichex.

This procedure is automatically performed at the end of a build.

Configurations

The following command can configure NuttX for this board, where <config> is one of the configurations listed below:

$ tools/configure.sh flipnclick-pic32mz:<subdir>

nsh

This is the NuttShell (NSH) using the NSH startup logic at apps/examples/nsh.

Note

UART3 is configured as the Serial Console. This assumes that you will be using a Mikroe RS-232 Click card in the mikroBUS B slot. Other serial consoles may be selected by re- configuring (see the section “Serial Consoles” above).

Note

By default, the Pinguino MIPs tool chain is used. This toolchain selection can easily be changed with make menuconfig.

Note

These are other things that you may want to change in the configuration:

CONFIG_PIC32MZ_DEBUGGER_ENABLE=n: Debugger is disabled CONFIG_PIC32MZ_TRACE_ENABLE=n: Trace is disabled CONFIG_PIC32MZ_JTAG_ENABLE=n: JTAG is disabled

nxlines

This is an NSH configuration that supports the NX graphics example at apps/examples/nxlines as a built-in application.

Note

This configuration derives from the nsh configuration. All of the notes there apply here as well.

Note

The default configuration assumes there is the custom HiletGo OLED in the mikroBUS A slot (and a Mikroe RS-232 Click card in the mikroBUS B slot). That is easily changed by reconfiguring, however. See the section entitled “HiletGo OLED” for information about this custom click card.

2018-02-10:

The debug output indicates that the nxlines example is running with no errors, however, nothing appears on the OLED display. I tried slot D with same result. I also ported the configuration to the Flip&Click SAM3X and got the same result. There could be SPI issues on the PIC32MX, but more likely that there is an error in my custom HiletGo Click. Damn!