Trinket M0
Overview
The Adafruit Trinket M0 is a tiny (27 mm x 15 mm) ARM development board with an onboard RGB LED, USB port, and range of I/O broken out onto 5 pins.
Hardware
ATSAMD21E18A ARM Cortex-M0+ processor at 48 MHz
256 KiB flash memory and 32 KiB of RAM
Internal trimmed 8 MHz oscillator
A user LED
An RGB DotStar LED
Native USB port
One reset button
Supported Features
The adafruit_trinket_m0 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.
adafruit_trinket_m0/samd21e18a target
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 unit3 |
|
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 |
|
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 |
||
LED strip |
on-board |
APA102 SPI LED strip1 |
|
MTD |
on-chip |
Flash node1 |
|
on-board |
Fixed partitions of a flash (or other non-volatile storage) memory1 |
||
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 driver2 |
|
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 |
Connections and IOs
The Adafruit Trinket M0 Learn site [1] has detailed information about the board including pinouts [2] and the schematic [3].
System Clock
The SAMD21 MCU is configured to use the 8 MHz internal oscillator with the on-chip PLL generating the 48 MHz system clock. The internal APB and GCLK unit are set up in the same way as the upstream Arduino libraries.
Serial Port
The SAMD21 MCU has 6 SERCOM based USARTs. On the Trinket, SERCOM0 is the Zephyr console and is available on pins 3 (RX) and 4 (TX). SERCOM2 is available on pins 2 (RX) and 0 (TX).
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 Trinket, SERCOM1 is used to drive the DotStar RGB LED. SERCOM0 can be put into SPI mode and used to connect to devices over pin 2 (MISO), pin 4 (MOSI), and pin 3 (SCK).
USB Device Port
The SAMD21 MCU has a USB device port that can be used to communicate with a host PC. See the USB device support sample applications for more, such as the USB CDC-ACM sample which sets up a virtual serial port that echos characters back to the host PC.
Programming and Debugging
The Trinket M0 ships the BOSSA compatible UF2 bootloader. The bootloader can be entered by quickly tapping the reset button twice.
Additionally, if CONFIG_USB_CDC_ACM is enabled then the bootloader
will be entered automatically when you run west flash.
Flashing
Build the Zephyr kernel and the Hello World sample application:
west build -b adafruit_trinket_m0 samples/hello_world
Connect the Trinket M0 to your host computer using USB
Connect a 3.3 V USB to serial adapter to the board and to the host. See the Serial Port section above for the board’s pin connections.
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
Tap the reset button twice quickly to enter bootloader mode
Flash the image:
west build -b adafruit_trinket_m0 samples/hello_world west flash
You should see “Hello World! adafruit_trinket_m0” in your terminal.