| Specifications | . |
|---|---|
| Flash (program memory) | 2048b/4096b |
| RAM | 128/256 bytes |
| EEPROM | 128/256 bytes |
| Bootloader | No |
| GPIO Pins | 17 |
| ADC Channels | None |
| PWM Channels | 3 |
| Interfaces | UART, USI |
| Clock options | Internal 0.5/1/4/8mhz, external crystal or clock up to 20mhz |
Tone() uses timer1. For best results, use pin 12, and 13, as this will use the hardware output compare to generate the square wave instead of using interrupts. In order to use Tone(), you must select Initialize Secondard Timers: Yes
When an Arduino sketch runs, prior to Setup() being called, a hidden init() function is called to set up the hardware. One of the things it does is configure the timers. Timer0 (used for millis) is always configured, but on the x313 series, due to the extremely limited flash, it is optional whether to initialize Timer1. If Timer1 is not initialized, Tone() and PWM on pins 12 and 13 will not work.
There is no hardware I2C peripheral. The USI can be used to provide I2C support with the TinyWireM or TinyWireS library
There is no hardware SPI peripheral. The USI can be used to provide SPI support with one of the TinySPI libraries
There is one full hardware Serial port, named Serial. It works the same as Serial on any normal Arduino - it is not a software implementation. Be aware that due to the limited memory on these chips the buffers are quite small.