XMC4500 Relax

There are to variants of this board: There is a Lite version that has fewer features, for example, no 32.768KHz crystal.

The current configurations support only the Lite version of the board.

Status

2017-03-21: The XMC4500 Relax boots into NSH, provides the NSH prompt, and the LEDs are working. But there is a problem with serial input. The most likely reason for this is there are no serial RX interripts.

Serial Console

Be default, UART0 (aka, USIC0, channel 0) is used as the serial console. The RX and TX pins is available:

RX     - P1.4, Connector X2, pin 17
TX     - P1.5, Connector X2, pin 16
GND    -       Available on pins 1-4 of either connector X1 or X2
VDD3.3 -       Available on pins 37-38 of either connector X1 or X2
VDD5   -       Available on pins 39-40 of either connector X1 or X2

A TTL to RS-232 converter or a USB TTL-to-USB serial adaptor is required. The notion of what is TX and what is RX depends on your point of view. With the TTL to RS-232 converter, I connect pin 17 to the pin labeled TX on the converter and pin 16 to the RX pin on the converter.

LEDs

The XMC4500 Relax Lite v1 board has two LEDs:

LED1 P1.1 High output illuminates
LED2 P1.0 High output illuminates

If CONFIG_ARCH_LEDS is not defined, then the user can control the LEDs in any way. The definitions provided in the board.h header file can be used to access individual LEDs.

These LEDs are not used by the board port 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

LED1

LED2

LED_STARTED

NuttX has been started

OFF

OFF

LED_HEAPALLOCATE

Heap has been allocated

OFF

OFF

LED_IRQSENABLED

Interrupts enabled

OFF

OFF

LED_STACKCREATED

Idle stack created

ON

OFF

LED_INIRQ

In an interrupt

N/C

N/C

LED_SIGNAL

In a signal handler

N/C

N/C

LED_ASSERTION

An assertion failed

N/C

N/C

LED_PANIC

The system has crashed

N/C

Blinking

LED_IDLE

MCU is is sleep mode

N/C

N/C

Thus if LED1 is statically on, NuttX has successfully booted and is, apparently, running normally. If LED2 is flashing at approximately 2Hz, then a fatal error has been detected and the system has halted.

Buttons

The XMC4500 Relax Lite v1 board has two buttons:

BUTTON1 P1.14 Low input sensed when button pressed
BUTTON2 P1.15 Low input sensed when button pressed

Configurations

Information Common to All Configurations

Each XMC4500 Relax configuration is maintained in a sub-directory and can be selected as follow:

.tools/configure.sh xmc4500-relax:<subdir>

See ‘.tools/configure.sh -h’ for a list of all options. The most typical are -l to select the Linux host or -c to select the Windows Cygwin host.

Before starting the build, make sure that your PATH environment variable includes the correct path to your toolchain.

And then build NuttX by simply typing the following. At the conclusion of the make, the nuttx binary will reside in an ELF file called, simply, nuttx:

make

The <subdir> that is provided above as an argument to the tools/configure.sh must be is one of the following.

NOTES:

  1. These configurations use the mconf-based configuration tool. To change any of these configurations using that tool, you should:

    1. Build and install the kconfig-mconf tool. See nuttx/README.txt see additional README.txt files in the NuttX tools repository.

    2. Execute ‘make menuconfig’ in nuttx/ in order to start the reconfiguration process.

  2. Unless stated otherwise, all configurations generate console output on UART0 (aka USIC0, channel 0) as described above under “Serial Console”. The relevant configuration settings are listed below:

    CONFIG_XMC4_USIC0=y
CONFIG_XMC4_USIC0_CHAN0_ISUART=y
CONFIG_XMC4_USIC0_CHAN1_NONE=y

CONFIG_UART0_SERIALDRIVER=y
CONFIG_UART0_SERIAL_CONSOLE=y

CONFIG_UART0_RXBUFSIZE=256
CONFIG_UART0_TXBUFSIZE=256
CONFIG_UART0_BAUD=115200
CONFIG_UART0_BITS=8
CONFIG_UART0_PARITY=0
CONFIG_UART0_2STOP=0

  3. All of these configurations are set up to build under Windows using the “GNU Tools for ARM Embedded Processors” that is maintained by ARM (unless stated otherwise in the description of the configuration).

That toolchain selection can easily be reconfigured using ‘make menuconfig’. Here are the relevant current settings:

Build Setup:

CONFIG_HOST_WINDOWS=y               : Window environment
CONFIG_WINDOWS_CYGWIN=y             : Cywin under Windows

System Type -> Toolchain:

CONFIG_ARM_TOOLCHAIN_GNU_EABI=y  : GNU ARM EABI toolchain

Configuration sub-directories

nsh:

Configures the NuttShell (nsh) located at examples/nsh. This configuration is focused on low level, command-line driver testing. It has no network.

NOTES:

  1. NSH built-in applications are supported.

Binary Formats:

CONFIG_BUILTIN=y           : Enable support for built-in programs

Application Configuration:

CONFIG_NSH_BUILTIN_APPS=y  : Enable starting apps from NSH command line

SPI

Using MAX6675 Thermocouple

There is a board support to use a MAX6675 connected to SPI2. In other to use it you need to enable these options:

CONFIG_XMC4_USIC=y
CONFIG_XMC4_USCI_UART=y
CONFIG_XMC4_USCI_SPI=y
CONFIG_XMC4_SPI2=y
CONFIG_XMC4_USIC1=y
CONFIG_XMC4_USIC1_CHAN0_ISSPI=y
CONFIG_XMC4_USIC1_CHAN1_ISUART=y
CONFIG_UART3_SERIAL_CONSOLE=y
CONFIG_SENSORS_MAX6675=y

These are the used SPI pins: SCLK = P0.11, MISO = P0.4 and CS = P0.2