Some news on the latest updates to Cosa.
1. ATtiny X5 and X4 is now supported. In reality only 8K devices, ATtiny84 and ATtiny85, are practical to work with. The others have too small memory size (SRAM). Most drivers have been ported to the ATtiny's; DHT11/22, OneWire DS18B20, LCD (PCD8544/ST7565), Virtual Wire, Ultra-sonic range module and more. More details: http://cosa-arduino.blogspot.com/2013/04/programming-attinyx5.html
2. Enhanced Virtual Wire Interface (VWI), VWI::Transceiver, with message acknowledgement, auto-retransmission and support for message type encoding/decoding. http://cosa-arduino.blogspot.com/2013/04/enhanced-virtual-wire-interface.html
3. Support for Home Automation NEXA/HomeEasy transmitter, receiver and "listener" objects. http://cosa-arduino.blogspot.com/2013/05/more-rf433-wireless-home-automation.html
4. Soft UART with IOStream integration. Mainly for debug trace output from ATtiny as this only requires a single pin for the TX.
5. Improved driver support for DHT11/22.
6. Cosa RTC includes three levels of "clocks"; micro-, milli- and second base. The millisecond timer base (Timer0/B) interrupt handling may be extended with a periodic callback for more accurate event timing.
7. BCD print support. May be used to avoid BCD-binary conversion when BCD data is not processed (such as when using the I2C Realtime Clock, DS1307, see DS1307::timekeeper_t::print(IOStream& stream, const char* format), https://github.com/mikaelpatel/Cosa/blob/master/Cosa/TWI/Driver/DS1307.cpp
8. LCD ST7565 support. As PCD8544 the LCD driver is integrated with IOStream. Graphics is performed using the OffScreen Canvas. This driver also supports text scroll without using a memory buffer. Please see the example sketch; https://github.com/mikaelpatel/Cosa/blob/master/examples/LCD/CosaST7565P/CosaST7565P.ino
9. New methods in the IOStream::Device interface; room(), number of bytes before output buffer is full, and peekchar(), access the next character in the input buffer without removing it. Updates to the implementations of the interface; UART, IOBuffer, etc.
10. Updated support for io vector buffers (iovec) and improved handling in communication drivers (TWI, SPI and VWI).
11. Major refactoring of Cosa TWI (I2C driver). Totally rewritten I2C/Two-Wire driver with higher level of application support. Reduced to less than 300 commented LOC.
12. Updated OffScreen Canvas to a template class. Improved robustness and performance.