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207 lines
7.0 KiB
Plaintext
207 lines
7.0 KiB
Plaintext
/**
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@defgroup boards_samr21-xpro Atmel SAM R21 Xplained Pro
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@ingroup boards
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@brief Support for the Atmel SAM R21 Xplained Pro board.
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## Overview
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The `SAMR21 Xplained Pro` is a compact evaluation board by Atmel featuring a
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ATSAMR21G18A SoC. The SoC includes a SAMD21 ARM Cortex-M0+ micro-controller
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bundled with Atmel's AT86RF233, a 2.4GHz IEEE802.15.4 compatible radio. For
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programming the MCU comes with 32Kb of RAM and 256Kb of flash memory.
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The samr21-xpro is available from various hardware vendors for ~40EUR (as of
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sep. 2014).
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## Hardware
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### MCU
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| MCU | ATSAMR21G18A |
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|:------------- |:--------------------- |
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| Family | ARM Cortex-M0+ |
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| Vendor | Atmel |
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| RAM | 32Kb |
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| Flash | 256Kb |
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| Frequency | up to 48MHz |
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| FPU | no |
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| Timers | 6 (1x 16-bit, 2x 24-bit, 3x 32-bit) |
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| ADCs | 1x 12-bit (8 channels) |
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| UARTs | max 5 (shared with SPI and I2C) |
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| SPIs | max 5 (see UART) |
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| I2Cs | max 5 (see UART) |
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| Vcc | 1.8V - 3.6V |
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| Datasheet | [Datasheet](http://www.atmel.com/Images/Atmel-42223-SAM-R21_Datasheet.pdf) |
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| Board Manual | [Board Manual](http://www.atmel.com/Images/Atmel-42243-SAMR21-Xplained-Pro_User-Guide.pdf)|
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### User Interface
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1 User button and 1 LED:
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| Device | PIN |
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|:------ |:--- |
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| LED0 | PA19 |
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| SW0 (button) | PA28 |
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### Radio
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The SAMR21 SoC includes an on-chip AT86RF233 radio. It is internally
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connected via SPI and some GPIO pins and behaves in exact the same way as
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externally connected SPI devices.
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| Sensor | AT86RF233 |
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|:------------- |:--------------------- |
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| Type | 2.4GHz IEEE802.15.4 radio |
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| Vendor | Atmel |
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| Datasheet | [Datasheet](http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-8351-MCU_Wireless-AT86RF233_Datasheet.pdf) |
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| Connected to | SPI_0 |
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| Pin Config: | |
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| Device | SERCOM4 |
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| MOSI | PB30 (OUT, SPI mosi) |
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| MISO | PC19 (IN, SPI miso) |
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| SCLK | PC18 (OUT, SPI sclk) |
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| CS | PB31 (OUT, GPIO output) |
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| IRQ | PB00 (IN, GPIO external interrupt) |
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| RSTN | PB15 (OUT, GPIO output) |
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| SLP_TR | PA20 (OUT, GPIO output) |
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## Implementation Status
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Please refer to [this tracker](https://github.com/RIOT-OS/RIOT/issues/1646)
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to see which projects are work in progress and who is the contact person for
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this.
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| Device | ID | Supported | Comments |
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|:------------- |:------------- |:------------- |:------------- |
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| MCU | samd21 | yes| |
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| Low-level driver | GPIO | yes | |
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| | PWM | yes | |
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| | UART | yes | |
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| | I2C | yes | |
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| | SPI | yes | |
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| | ADC | yes | PA04 & PA05 disabled by default due to EDBG's use of them for UART, can be enabled from `periph_conf.h`|
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| | USB | yes | |
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| | RTT | yes | |
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| | RTC | yes | |
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| | Timer | yes | |
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| Radio Chip | AT86RF233 | yes | using at86rf2xx driver |
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## Flashing the device
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Connect the device to your Micro-USB cable using the port labeled as *EDBG*.
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The standard method for flashing RIOT to the samr21-xpro is using [edbg](https://github.com/ataradov/edbg).
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by calling: `make BOARD=samr21-xpro -C tests/leds flash`
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Note that on Linux, you will need libudev-dev package to be installed.
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Users can also use openOCD to flash and/or debug the board using:
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`PROGRAMMER=openocd make BOARD=samr21-xpro -C tests/leds flash`
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On Linux you will have to add a **udev** rule for hidraw, like
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```
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bash
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echo 'KERNEL=="hidraw*", SUBSYSTEM=="hidraw", MODE="0664", GROUP="plugdev"' \
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| sudo tee -a /etc/udev/rules.d/99-usb.rules
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sudo service udev restart
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```
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### Arch Linux
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With yaourt:
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```
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yaourt -S libudev0
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yaourt -S hidapi-git
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yaourt -S openocd-git
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# edit PKGBUILD, make sure "hidapi-libusb" is in "_features"
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```
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The **udev** rules for Arch differ a little from the example given above:
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```
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bash
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echo 'KERNEL=="hidraw*", SUBSYSTEM=="hidraw", MODE="0664", GROUP="uucp"' \
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| sudo tee -a /etc/udev/rules.d/99-usb.rules
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sudo udevadm control --reload
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```
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### Ubuntu
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See http://watr.li/samr21-dev-setup-ubuntu.html
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## Connecting multiple boards
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If you have multiple boards connected to the same computer and want to flash,
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this is what you can do:
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First, run `make list-ttys`. This will show you a list of currently connected
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boards, their serial numbers and the names of their TTYs:
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Atmel Corp. EDBG CMSIS-DAP serial: 'ATML2127031800002124', tty(s):
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ttyACM0
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Atmel Corp. EDBG CMSIS-DAP serial: 'ATML2127031800002145', tty(s):
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ttyACM1
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knowing your serial number, you can flash, open a terminal or debug a
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specific board like this:
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BOARD=samr21-xpro SERIAL="ATML2127031800002124" make flash
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BOARD=samr21-xpro SERIAL="ATML2127031800002124" make term
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BOARD=samr21-xpro SERIAL="ATML2127031800002124" make debug
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## Accessing STDIO via UART
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STDIO is available through the edbg debugger.
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Use the `term` target to open a terminal:
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make BOARD=samr21-xpro -C examples/hello-world term
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RTS / CTS hardware flow control is available on `UART_DEV(0)` and
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`UART_DEV(1)`. This is unavailable when using STDIO directly through
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the debugger since it does not support it. Therefore to use hardware
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flow control an external FTDI device must be connected to the board's
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rx, tx, cts & rts matching pin headers, eg. for `UART_DEV(0)` to
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`PA5`, `PA4`, `PA6` & `PA7` (respectively) on EXT1 headers.
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## Known Issues / Problems
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### 64 character input limit on EDBG UART
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When using STDIO directly through the debugger UART, no more than 64 bytes can
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be read at once. This does limit the length of shell command lines to 63 bytes
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(since a newline is needed) when using a terminal that only transmits whole lines.
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(e.g. pyterm).
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### I2C
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When connecting an I2C device and a logic analyzer to an I2C port at the same
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time, the internal pull-up resistors are not sufficient for stable bus
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operation. You probably have to connect external pull-ups to both bus lines. 10K
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is a good value to start with.
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### Stack sizes
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The default stack sizes have not been tuned properly yet. If in doubt why
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your application crashes try increasing the default stack sizes and use `ps` to
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find out how much stack is being used.
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Tracked in https://github.com/RIOT-OS/RIOT/issues/2228
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### User Button
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When using the SW0 user button as interrupt source it appears that this is
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triggered when just tipping on the button and not really pressing it.
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### Flashing might not work in Virtual Box with macOS as host
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It might happen that flashing through OpenOCD works once inside Virtual Box.
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But when you try to flash again, you could get a CMSIS-DAP related error. It
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seems to only happen with USB 3.0 ports. You can take a look at
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[Vagrant](http://en.wikipedia.org/wiki/Vagrant_%28software%29) and use a virtual
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Linux to run the virtual RIOT, and flash from macOS.
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*/
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