I posted the SPIFlash library I was talking about in previous posts. I have not found a convenient library for that purpose hence this library written by myself.
Get it at my Github repository: http://github.com/LowPowerLab/SPIFlash
Also added a basic usage example under the library.
The All-About-Moteino page describes how you can add a flash chip to your Moteino or even to your Arduino. To access this chip you will need a library such as this one to conveniently read or write bytes to the chip. I would recommend getting used to the chip itself by doing some reading in the datasheet of the chip you are using – there are some particularities as to how these chips work. The library attemps to abstract most of these things so you don’t have to worry about them. At the very least please read the comments in the code for now. Soon I will hopefully add more info and tutorials. Stay tuned for the complete solution code for wireless/in-field programming of Arduino/Moteino using this library. I am working to get all that code organized and posted on this blog.
I’ve been using the RF12 library from Jeelabs for some time for my Moteino testing. This worked just fine and it was a great starting point. However some things were really confusing and I spent a lot of time redoing the same thing over and over again (eg. copy paste from known working code) just because there was a lot of code-overhead to do simple things like sending, receiving, and ACK management, and of course I couldn’t remember any of the functions or macros. Right from start, the need emerged to tweak it into a more flexible and more configurable library, so I kept hacking and modding it until it dawned on me… a new library had to be born. So I decided to completely rewrite it, and wrap the useful functionality in a dedicated C++ class. I modified some of the core features of the Jeelabs version, like adding another header byte to allow 7-bit source and destination addresses (Jeelabs only supports either source or destination in an attempt to save 1 byte), and allow low level configuration of the radio. This yielded a clean and easy to use, yet powerful library (at least it made my life easy). Here’s a summary:
- easy API with a few simple functions for basic usage
- 127 possible nodes on 256 possible networks
66 128 bytes max message length
- customizable transmit power (8 levels) for low-power transmission control
- customizable air-Kbps rate allows fine tuning the transmission reliability vs speed (transmitting slower is more reliable but takes more time which implies more power usage)
- Sleep/Wakeup functionality for power saving
- Low battery detector with customizable low voltage threshold
- Interrupt driven
- Support for targeted ACK instead of broadcasted ACK (possible because of the new source byte in the header)
- encryption with XXTEA algorithm by David Wheeler, adapted from http://en.wikipedia.org/wiki/XXTEA
- Support for these chips: ATMega8 family (ATmega168, ATMega328) ATMega2560, ATMega1280, ATMega644P, ATTiny84, ATTiny44, ATMega32u4. So far only tested on ATMega 328/P
- The source code and examples are on GitHub: RFM12 Library