It s useful to write systems in matrix form. While we looked at several examples, including the general form of a system of linear equations, it s useful just to look at a simple, special case. The system

SPI lib for atmega168. DON USE Wrk? UNOS void spi_init(void) { /* Set MOSI and SCK output */ DDR_SPI |= _BV(DD_MOSI) | _BV(DD_SCK) DDR_SPI &= ~_BV(DD_MISO) /* Enable SPI, Master, set clock rate fck/128 */ SPCR = _BV(SPE) | _B