The memory map of the ELF file does not take the bootloader into account. If AVaRICE complains that synchronization with the device is not possible after having it flashed, the device might need a cold boot to enable debugWIRE again. Warning For flashing the device via ISP, avrdude will temporarily disable debugWIRE. With the AVR Dragon, debugging is as simple as running: make BOARD=arduino-nano debug So don't enable debugging unless you have an AVR Dragon or another plan on how to disable debugging again. But this requires a programmer/debugger that can be used as both ISP and debugWIRE debugger using the same connector. Recent versions of avrdude will use the debugWIRE interface to temporarily disable debugWIRE and restore the RESET pin's default behavior in order to use the ISP. Note You can use a different ISP to enable debugging, but disabling it again will only work with the AVR Dragon: The ISP will require the RESET pin to work, but the RESET pin is re-purposed for debugWIRE when debugging is enabled. dragon_isp in case of the AVR Dragon): avrdude -p m328p -c -U hfuse:w:0x9a:mĪnd disable debugging via: avrdude -p m328p -c -U hfuse:w:0xda:m You can enable debugWIRE debugging by running (replace by the name of your programmer, e.g. The exact fuse settings for debugging and the default fuse setting are these: Fuse In order to use On-Chip Debugging, the DWEN bit in the high fuse needs to be enabled (set to zero). The latest release cannot be compiled on anything but historic platforms and contains bugs that prevent it from debugging the ATmega328P anyway. If you need to compile it by hand, go for the latest SVN revision. After this modification, flashing via bootloader requires a manual press on the reset button. You can either carefully de-solder it (which allows you to solder it back in after debugging), or just break it off with pinch-nose pliers (which usually destroys the capacitor, making the modification permanent). In order to use on-chip debugging, the capacitor needs however to be disconnected from the reset pin. This is particularly useful during programming via the bootloader (without external ISP programmer), as avrdude can trigger the reset and, thus, start the bootloader without the user having to press a button. This allows the device to be automatically reset when you connected to the board via a serial. On the Arduino Nano the RESET pin of the MCU is connected to a 100 nF capacitor, which in turn is connected to the DTR pin of the FT232RL USB-UART bridge. So at least can use it for just about every AVR device. In order to be able to use On-Chip Debugging you will need the AVR Dragon, which is the cheapest least expensive programmer and debugger available that supports programming via SPI ("normal ISP"), High Voltage Serial Programming, and Parallel Programming, as well as debugging via JTAG, debugWIRE, PDI and aWire. If the bug cannot be reproduced, limited on chip debugging is possible on the Arduino Nano nonetheless. If the same issue can be reproduced on an Arduino Mega2560, which supports JTAG, it will be much easier and more productive to debug your code on the Arduino Mega2560. While debugWIRE has the advantage of only using the RESET pin to transfer data, the features provided are extremely limited. On-Chip Debugging on the Arduino Nano is not supported via the usual JTAG interface used in ATmega MCUs with higher pin counts, but via debugWIRE. after restarting the device with the reboot shell command, this is likely caused by an issue with the stock bootloader that can be solved by using Optiboot as bootloader instead (see above). Don't forgot to also update the fuse settings to set the bootloader size to 256 words (512 bytes).Ĭompile and flash with make BOARD=arduino-nano ATMEGA_BOOTLOADER=optiboot flash or use export ARDUINO_NANO_BOOTLOADER=optiboot in order to not have to specify the bootloader during compilation and flashing. Refer to the project page for instructions on how to build an flash the bootloader. Optiboot also is smaller (512 byte instead of 2 KiB), so that 1.5 KiB more program memory is available for RIOT. You can use the Optiboot bootloader instead of the stock bootloader for faster programming. We use the open avrdude tool to write the new code into the ATmega328p's flash It is like many Arduinos extensible by using shields.ģ2 KiB (2 KiB reserved for the bootloader)įlashing RIOT on the Arduino Nano is quite straight forward, just connect your Arduino Nano via the USB connector to your host computer and type: It is based on Atmel's AVR architecture and sports an ATmega328p MCU. The Arduino Nano is the cheapest member of the Arduino family.
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