# Che Cosa?
Cosa is an object-oriented platform for Arduino. It replaces the Arduino and Wiring library with a large set of integrated classes that support the full range of AVR/ATmega/ATtiny internal hardware modules; all pin modes, Digital, and Analog Pins, External and Pin Change Interrupts, Analog Comparator, PWM, Watchdog, Timer0 (RTC), Timer1 (Servo), UART, USI, SPI, TWI and EEPROM.
Cosa is implemented as an Arduino IDE core. The Cosa platform can be used with almost all Arduino boards and ATtiny/ATmega processors. All classes may be compiled for all variants. The limitations are hardware resources.
Though object-oriented with optional operator overloading syntax, Cosa is between 2-10X faster than Arduino with regard to digital pin functions. This comes with a small price-tag; memory, 4 bytes per digital pin and 9 bytes per analog pin. Cosa analog pin objects holds the latest sample and allows an event handler. See the benchmarks in the examples directory for further details.
Cosa contains several data streaming formats for message passing and data streaming. Google Protocol Buffers are supported together with a data streaming format (Ciao) for encoding of C/C++ language data types such as strings, integer and floating pointer numbers into a binary format. It may be used for a number of applications; tracing, remote procedure calls, data exchange between Arduino devices, etc. The format allows user data types to be defined and values exchanged without additional encoding.
The primary programming paradigm is object-oriented and state-machine, event driven, with proto-threads or multi-tasking. There is a large number of device drivers available for SPI, I2C (TWI) and 1-Wire (OWI). A strict directory structure is used to organize the Cosa/driver source code. Sub-directories are used for each driver type. This allows a foundation for scaling and configuration.
Cosa uses the Arduino IDE and build system. Cosa classes are included with prefix, e.g. "Cosa/FileName.hh". There is also (for Linux) an advanced build system that allow make-based build and caching of core library without writing makefiles. It also support the typical development steps; compile, upload, and serial monitoring.
To improve debugging and testing there is assert/trace/syslog style support. The IOStream class allows output to both serial wire/wireless communication (UART/VWIO) and small TFT displays (such as the ST7735, ST7565, HD44780, and PCD8544). The Cosa LCD class extends IOStream::Device with additional common LCD functions. The Cosa LCD Menu class adds a simple framework for creating menu systems with program state such as integer ranges, bitsets and enumeration variables. All menu data structures are stored in program memory and the SRAM requirement is minimum. A macro set hides the details of creating the data structures in program memory.
The drawing Canvas class supports basic drawing operation and scripting to reduce program memory footprint. The Canvas class also supports drawing of icons and a large set of fonts.
The popular VirtualWire library has been refactored to the object-oriented style of Cosa (VWI) and extended with three additional codecs; Manchester, 4B5B and Bitstuffing. This allows basic ultra cheap wireless nodes with RF315/433 receiver and transmitter. For more advanced wireless connections there is also a driver for the Nordic Semiconductor NRF24L01+ chip, which allows low-power wireless communication of up to 2 Mbps in the 2.4GHz band, and the TI CC1101 Low-Power Sub-1 GHz RF Transceiver.
The goal of this project is to provide an efficient programming platform for rapid prototyping of "Internet-of-things"-devices. There is an Ethernet/Socket with W5100 Ethernet controller device driver. This implementation allows streaming direct to the device buffers. Cosa also implements a number of IP protocols; DNS, DHCP, NTP, HTTP, and SNMP, and high level messaging such as MQTT and ThingSpeak. There is also support for the TI CC3000 WiFi module.
Unfortunately Cosa is not a beginners entry level programming platform, though following some of the design patterns in Cosa will help beginners build more complex small scale embedded systems with richer concurrency and low power consumption.