SAM E70 Xplained

Overview

The SAM E70 Xplained evaluation kit is a development platform to evaluate the Atmel SAM E70 series microcontrollers.

SAM E70 Xplained

Hardware

  • ATSAME70Q21 ARM Cortex-M7 Processor
  • 12 MHz crystal oscillator
  • 32.768 kHz crystal oscillator (not populated)
  • AT24MAC402 EEPROM
  • IS42S16100E 16 Mb SDRAM
  • SD card connector
  • Ethernet port
  • Micro-AB USB device
  • Micro-AB USB debug interface supporting CMSIS-DAP, Virtual COM Port and Data Gateway Interface (DGI)
  • JTAG interface connector
  • One reset and one user pushbutton
  • One green user LED

Supported Features

The sam_e70_xplained board configuration supports the following hardware features:

Interface Controller Driver/Component
NVIC on-chip nested vector interrupt controller
SYSTICK on-chip systick
UART on-chip serial port
USART on-chip serial port
I2C on-chip i2c
ETHERNET on-chip ethernet
WATCHDOG on-chip watchdog

Other hardware features are not currently supported by Zephyr.

The default configuration can be found in the Kconfig boards/arm/sam_e70_xplained/sam_e70_xplained_defconfig.

Connections and IOs

The SAME70-XPLD User Guide has detailed information about board connections.

System Clock

The SAM E70 MCU is configured to use the 12 MHz external oscillator on the board with the on-chip PLL to generate a 300 MHz system clock.

Serial Port

The ATSAME70Q21 MCU has five UARTs and three USARTs. One of the USARTs is configured for the console and is available as a Virtual COM Port via EDBG USB chip.

Programming and Debugging

Flashing the Zephyr project onto SAM E70 MCU requires the OpenOCD tool. Support for Atmel SAM E microcontroller series was added in OpenOCD release 0.10.0. The current OpenOCD version available in the Zephyr SDK is 0.9 and unfortunately it does not support Atmel SAM E microcontrollers. Since few, if any major Linux distributions currently offer OpenOCD version 0.10.0 as a package you will have to compile and install it yourself. Make sure to enable CMSIS-DAP support as this is the debug interface used by the on board EDBG chip.

By default a factory new SAM E70 chip will boot SAM-BA boot loader located in the ROM, not the flashed image. This is determined by the value of GPNVM1 (General-Purpose NVM bit 1). The flash procedure will ensure that GPNVM1 is set to 1 changing the default behavior to boot from Flash.

If your chip has a security bit GPNVM0 set you will be unable to program flash memory or connect to it via a debug interface. The only way to clear GPNVM0 is to perform a chip erase procedure that will erase all GPNVM bits and the full contents of the SAM E70 flash memory:

  • With the board power off, set a jumper on the J200 header.
  • Turn the board power on. The jumper can be removed soon after the power is on (flash erasing procedure is started when the erase line is asserted for at least 230ms)

Flashing

  1. Build the Zephyr kernel and the application:

    $ cd $ZEPHYR_BASE/samples/hello_world/
$ make BOARD=sam_e70_xplained

  2. Connect the SAM E70 Xplained board to your host computer using the USB debug port.

  3. Run your favorite terminal program to listen for output. Under Linux the terminal should be /dev/ttyACM0. For example:

    $ minicom -D /dev/ttyACM0 -o

    The -o option tells minicom not to send the modem initialization string. Connection should be configured as follows:

    • Speed: 115200
    • Data: 8 bits
    • Parity: None
    • Stop bits: 1

  4. To flash the image, assuming the OpenOCD tool is already installed, enter:

    $ make BOARD=sam_e70_xplained flash

    The command will also verify that the image was programmed correctly, reset the board and run the Zephyr application.

    You should see “Hello World!” in your terminal.

Debugging

  1. Connect the SAM E70 Xplained board to your host computer using the USB debug port.

  2. Start GDB server on your host computer

    $ openocd -f board/atmel_same70_xplained.cfg&

  3. You can now use GDB remote debugging to connect to the target board. By default GDB server will listen on port 3333.