SAM D21 Xplained Pro Evaluation Kit
Overview
The SAM D21 Xplained Pro evaluation kit is ideal for evaluation and prototyping with the SAM D21 Cortex®-M0+ processor-based microcontrollers. The kit includes Atmel’s Embedded Debugger (EDBG), which provides a full debug interface without the need for additional hardware.
Hardware
SAMD21J18 ARM Cortex-M0+ processor at 48 MHz
32.768 kHz crystal oscillator
256 KiB flash memory and 32 KiB of RAM
One yellow user LED
One mechanical user push button
One reset button
On-board USB based EDBG unit with serial console
Supported Features
The samd21_xpro board supports the hardware features listed below.
- on-chip / on-board
- Feature integrated in the SoC / present on the board.
- 2 / 2
-
Number of instances that are enabled / disabled.
Click on the label to see the first instance of this feature in the board/SoC DTS files. -
vnd,foo -
Compatible string for the Devicetree binding matching the feature.
Click on the link to view the binding documentation.
Type |
Location |
Description |
Compatible |
|---|---|---|---|
CPU |
on-chip |
ARM Cortex-M0+ CPU1 |
|
ADC |
on-chip |
Atmel SAM0 family ADC1 |
|
ARM architecture |
on-chip |
Atmel SAM0 multi-protocol (UART, SPI, I2C) SERCOM unit1 |
|
on-chip |
For locating the Device ID (serial number) on Atmel SAM0 devices1 |
||
Clock control |
on-chip |
Atmel SAM0 Main Clock Controller (MCLK)1 |
|
on-chip |
Atmel SAMD0 Generic Clock Controller (GCLK)1 |
||
Counter |
on-chip |
Atmel SAM0 basic timer counter (TC) operating in 32-bit wide mode2 |
|
DAC |
on-chip |
Atmel SAM0 family DAC1 |
|
DMA |
on-chip |
Atmel SAM0 DMA controller1 |
|
Flash controller |
on-chip |
Atmel SAM0 NVMC (Non-Volatile Memory Controller)1 |
|
GPIO & Headers |
on-chip |
SAM0 GPIO PORT node2 |
|
I2C |
on-chip |
Atmel SAM0 series SERCOM I2C1 |
|
Input |
on-board |
Group of GPIO-bound input keys1 |
|
Interrupt controller |
on-chip |
ARMv6-M NVIC (Nested Vectored Interrupt Controller) controller1 |
|
on-chip |
Atmel SAM0 series External Interrupt Controller1 |
||
LED |
on-board |
Group of GPIO-controlled LEDs1 |
|
on-board |
Group of PWM-controlled LEDs1 |
||
MTD |
on-chip |
Flash node1 |
|
Pin control |
on-chip |
Atmel SAM0 PINMUX2 |
|
on-chip |
Atmel SAM0 Pinctrl Container1 |
||
PWM |
on-chip |
Atmel SAM0 TCC in PWM mode1 |
|
RTC |
on-chip |
Atmel SAM0 RTC1 |
|
Serial controller |
on-chip |
Atmel SAM0 SERCOM UART driver3 |
|
SPI |
on-chip |
Atmel SAM0 SERCOM SPI controller1 |
|
SRAM |
on-chip |
Generic on-chip SRAM description1 |
|
Timer |
on-chip |
ARMv6-M System Tick1 |
|
USB |
on-chip |
Atmel SAM0 USB in device mode1 |
|
Watchdog |
on-chip |
Atmel SAM0 watchdog1 |
Pin Mapping
The SAM D21 Xplained Pro evaluation kit has 3 GPIO controllers. These controllers are responsible for pin muxing, input/output, pull-up, etc.
For more details please refer to SAM D21 Family Datasheet [1] and the SAM D21 Xplained Pro Schematic [2].
Default Zephyr Peripheral Mapping:
SERCOM0 USART TX : PA10
SERCOM0 USART RX : PA11
SERCOM1 USART TX : PA16
SERCOM1 USART RX : PA19
SERCOM2 I2C SDA : PA08
SERCOM2 I2C SCL : PA09
SERCOM3 USART TX : PA22
SERCOM3 USART RX : PA23
SERCOM5 SPI MISO : PB16
SERCOM5 SPI MOSI : PB22
SERCOM5 SPI SCK : PB23
USB DP : PA25
USB DM : PA24
GPIO SPI CS : PB17
GPIO/PWM LED0 : PB30
System Clock
The SAMD21 MCU is configured to use the 32.768 kHz external oscillator with the on-chip PLL generating the 48 MHz system clock.
Serial Port
The SAMD21 MCU has six SERCOM based USARTs with three configured as USARTs in this BSP. SERCOM3 is the default Zephyr console.
SERCOM0 9600 8n1
SERCOM1 115200 8n1
SERCOM3 115200 8n1 connected to the onboard Atmel Embedded Debugger (EDBG)
PWM
The SAMD21 MCU has 3 TCC based PWM units with up to 4 outputs each and a period
of 24 bits or 16 bits. If CONFIG_PWM_SAM0_TCC is enabled then LED0 is
driven by TCC0 instead of by GPIO.
SPI Port
The SAMD21 MCU has 6 SERCOM based SPIs. On the SAM D21 Xplained Pro, SERCOM5 is connected to an 8 megabit SPI flash.
Programming and Debugging
The SAM D21 Xplained Pro comes with a Atmel Embedded Debugger (EDBG). This provides a debug interface to the SAMD21 chip and is supported by OpenOCD.
Flashing
Build the Zephyr kernel and the
hello_worldsample application:west build -b samd21_xpro samples/hello_world
Connect the SAM D21 Xplained Pro to your host computer using the USB debug port.
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
To flash an image:
west build -b samd21_xpro samples/hello_world west flash
You should see “Hello World! samd21_xpro” in your terminal.