Gary AG5TX observes in a post to the BITX20 list that Protoneer has a NANO-ARM board offering for $10 + $5 (US) shipping. This may be a viable low cost pin compatible upgrade to the nano board on the Radunio with a direct board swap out. This will give more headroom for coding +more features and still work in the Arduino IDE environment.
https://wiki.protoneer.co.nz/NANO-ARM
The NANO-ARM has the following features:
- Runs at 48MHz (Atmel SAMD21)
- 256KB FLASH Memory
- 32KB RAM
- Pin compatible with Arduino Nano but runs at 3.3V
- SAMD21 micro-controller same as used on a Arduino Zero’s.
- Built in USB
- Arduino Zero bootloader pre-loaded.
- 20 I/O pins with 5 extra pins that can be used for I2C/SPI or I/O
- 6 Analog Pins(ADC) with 12-bit resolution (4096 resolution point vs Arduino Uno’s 1024)
- 1 Digital to Analog(DAC) pin with 10-bit resolution.
- Designed and Manufactured in New Zealand
Why the Protoneer?
Gary’s selection criteria were:
- More Flash, so people don’t have to choose which options from the already developed software they could load, and more headroom for further development.
- More SRAM.
- Supported by the familiar Arduino IDE, where the software work is being done.
The Protoneer is:
- Pin compatible with the Nano for direct replacement on the Raduino board without the need to spin an adapter board (cost with shipping adder)
- Reasonable total cost of the complete upgrade, so it is an option more aligned to Farhan’s goal of a $100 radio.
- Can be changed over in a timely manner.
Gary has ordered a board, but has not yet received it or even begun to look at the software changes that will be necessary. I do know that there will be small changes needed on which serial object is called. There may be other quirks.
The board is 3.3V so the impact of that will need to be vetted. (I see 3.3V as being beneficial). There’s also a Real Time Clock, but he didn’t spot the familiar Vbat for a coin cell.
Adafruit seems to be doing a lot of development with the SAMD21, there could be trickle down from that, or at least re-assuring of the SAMD21 core.