Microduino CoreRF

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When using this board with RIOT, set the BOARD variable to microduino-corerf in your Makefile. If you follow the standard RIOT project structure, your Makefile should look like this:

# name of your application
APPLICATION = hello-world

# Change this to your board if you want to build for a different board
BOARD ?= microduino-corerf

# This has to be the absolute path to the RIOT base directory:
RIOTBASE ?= $(CURDIR)/RIOT

include $(RIOTBASE)/Makefile.include

Support for the Microduino CoreRF board

Hardware

Pinout

corerf-pinout

Warning: Unlike on other ATmega MCUs, the GPIOs are not 5V tolerant.

Note: The 5V pin cannot be used to power the board, as the board is not equipped with an voltage regulator. The pin is therefore not connected. But it can be used to pass 5V to shields, if connected to a 5V supply voltage.

Board

The board is just a breakout for the ATmega128RFA1 MCU.

MCU Details

MCU	ATmega128RFA1
Family	ATmega
Vendor	Atmel
Package	QFN/MLF
SRAM	16KiB
Flash	128KiB
EEPROM	4KiB
Core Frequency	8MHz (16MHz no power save mode)
Oscillators	32.768 kHz & 16 MHz
Timer	6 ( 2x8bit & 4x16bit )
Analog Comparator	1
ADCs	1x 15 channel 6 to 12-bit
USARTs	2
SPIs	3 (1 SPI & 2 USART SPI)
I2Cs	1 (called TWI)
Vcc	1.8V - 3.6V
Datasheet / Reference Manual	Datasheet and Reference Manual
Board Manual	Wiki Page

The MCU comes with a 2.4 GHz IEEE 802.15.4 radio that is compatible with the Atmel AT86RF23x line of transceivers with the only difference being that it is not being accessed over an SPI bus, but instead the radio registers are directly mapped into memory.

Peripheral interfaces SPI and I2C

According to the wiki, SPI and I2C pins are the following:

SPI	Original Pin Name	Map Pin Name
SS	PB4	D10
MOSI	PB2	D11
MISO	PB3	D12
SCK	PB1	D13

I2C	Original Pin Name	Map Pin Name
SDA	PD1	D18
SCL	PD0	D19

Flashing RIOT

Flashing RIOT on the CoreRF is done using the SPI method. Using a cheap FT232H breakout board, connect the board as follows:

FT232H	Microduino CoreRF
D0	D13 (SCK)
D1	D11 (MOSI)
D2	D12 (MISO)
D3	RST (Reset)
3.3V	3.3V
GND	GND

Now you can simply type

make flash BOARD=microduino-corerf

This should take care of everything!

You will need a separate adapter for UART:

FT232R	Microduino CoreRF
TX	D0
RX	D1

Troubleshooting

Using the external crystal oscillator (Transceiver Crystal Oscillator) and deep sleep

When the external crystal oscillator is used as system clock and the device is put into deep sleep mode it seems that the clocks for all peripherals are enabled and set to the smallest divider (highest frequency). This leads to a higher power consumption. When the device should be put into deep sleep it is recommended to use the internal RC oscillator as system clock source.

Pin Change Interrupts

More pins can be used for hardware interrupts using the Pin Change Interrupt feature. See boards_common_atmega for details.

Debugging

The ATmega128RFR1 supports JTAG debugging. To use the JTAG debugging an external JTAG debugger is required. There are several options for this MCU/board:

Hint: The AVR Dragon is the ~~cheapest~~ least expensive debugger and also is compatible with almost every AVR MCU.

Warning: With the default fuse settings, on chip debugging is disabled.

Note: If you are using a different debugger than the AVR Dragon, you have to export the AVR_DEBUGDEVICE environment variable to the required flag to pass to AVaRICE, e.g. when using the Atmel-ICE you have to export AVR_DEBUGDEVICE=--edbg. If the debug device is not connected via USB, you also need to export AVR_DEBUGINTERFACE to the correct value.

JTAG Pin Mapping

Pin	Pin Label	Signal	AVR Dragon Pin
PF7	A0	TDI	JTAG-9
PF6	A1	TDO	JTAG-3
PF5	A2	TMS	JTAG-5
PF4	A3	TCK	JTAG-1
VDD	3V3	VTG	JTAG-4
GND	GND	GND	JTAG-2

Fuse Settings

Be aware that changing the fuse settings can “brick” your MCU, e.g. if you select a different clock setting that is not available on your board. Or if you disable all options for programming the MCU.

You can always de-brick your MCU using high voltage programming mode, which can also be done using the AVR Dragon. But being careful to not brick your MCU in the first place is clearly the better option ;-)

In the following it is assumed that you connect the Dragon ISP header to the Microduino CoreRF for ISP programming.

Default Fuse Settings

The default fuse settings of the Microduino CoreRF are: E:F5, H:DA, L:FF. These settings can be restored via from the OCD settings via:

avrdude -c dragon_isp -p m128rfa1 -U hfuse:w:0xda:m

If you touched other fuse settings, you can restore the fuse settings using:

avrdude -c dragon_isp -p m128rfa1 -U efuse:w:0xf5:m -U hfuse:w:0xda:m -U lfuse:w:0xff:m

On-Chip Debugging Fuse Settings

To enable on-chip debugging, the JTAGEN (enable JTAG) and the OCDEN (enable on-chip debugging) bits should be set: E:F5, H:1A, L:FF. This can be done (when starting with the default settings) via:

avrdude -c dragon_isp -p m128rfa1 -U hfuse:w:0x1a:m