/* print.c numbers and text strings */ // Arduino UNO R3 // AVR_ATmega328P #define F_CPU 16000000UL #include // register names/addresses and bit names/numbers #include // for the nop instruction #include // macros for strings in program memory #define DECIMAL_MARK ',' #define SIGN 1 #define NOSIGN 0 void init_uart( void ); unsigned char getchar_uart( void ); void putchar_uart( unsigned char ); void string_out_uart( char * ); // uses strings stored in RAM void string_out_uart_P( const char * ); // uses string constants stored in program memory void decimal_out_uart( unsigned int, unsigned char, char); // parameters: number, decimals, with or without sign int main(void) { init_uart(); string_out_uart_P( PSTR("The voltage is: ") ); decimal_out_uart( 12345, 1, NOSIGN ); // 1 fixed decimal and no sign string_out_uart_P( PSTR(" [V]\r\n") ); string_out_uart_P( PSTR("The signed voltage is: ") ); decimal_out_uart( 12345, 2, SIGN ); // 2 fixed decimals and sign string_out_uart_P( PSTR(" [V]\r\n") ); string_out_uart_P( PSTR("The signed voltage is: ") ); decimal_out_uart( -12345, 3, SIGN ); // 3 fixed decimals and sign string_out_uart_P( PSTR(" [V]\r\n") ); while(1) { _NOP(); // will not be removed by compiler optimization } return 0; /* never reached */ } /* *********************************** */ /* FUNCTIONS */ /* *********************************** */ void init_uart( void ) { // Bits in UCSR0B register: "RXCIE0 TXCIE0 UDRIE0 RXEN0 TXEN0 UCSZ02 RXB80 TXB80" UCSR0B |= (1<<(RXEN0)) | (1<<(TXEN0)); // "----1---" // Bits in UCSR0C register: "UMSEL01 UMSEL00 UPM01 UPM00 USBS0 UCSZ01/UCPHA0 UCSZ01/UCPHA0 UCPOL0" UCSR0C |= (1<<(UCSZ01)) | (1<<(UCSZ00)); // "-----11-" UBRR0 = 103; // Baud prescaler 103 -> 9600 Baud } unsigned char getchar_uart( void ) { unsigned char ch; // Bits in UCSR0A register: "RXC0 TXC0 UDRE0 FE0 DOR0 UPE0 U2X0 MPCM0" // wait until a byte is ready to read while( ( UCSR0A & ( 1<<(RXC0) ) ) == 0 ){} // grab the byte from the serial port ch = UDR0; return ch; } void putchar_uart( unsigned char ch ) { // Bits in UCSR0A register: "RXC0 TXC0 UDRE0 FE0 DOR0 UPE0 U2X0 MPCM0" // wait until the port is ready to be written to while( ( UCSR0A & ( 1<<(UDRE0) ) ) == 0 ){} // write the byte to the serial port UDR0 = ch; } void string_out_uart( char * string ) // use for strings in RAM { while (* string != '\0') putchar_uart(*string ++ ); } void string_out_uart_P( const char * string ) // use for strings in program memory { while ( pgm_read_byte( string ) != 0x00 ) putchar_uart( pgm_read_byte( string ++) ); } void decimal_out_uart( signed int number, unsigned char fixed_decimals, char format ) { unsigned char i; unsigned int divisor = 10000; if (format == SIGN) { if (number < 0 ) { putchar_uart( '-' ); number = -number; } else putchar_uart( '+' ); } for(i=0; ;i++) { putchar_uart( (unsigned char)(number/divisor) + '0' ); if( i==4 ) break; if( i== ( 4 - fixed_decimals) ) putchar_uart( DECIMAL_MARK ); number %= divisor; divisor /= 10; } } /* *********************************** */ /* HARDWARE */ /* *********************************** */ /* Chip ATMega328 Arduino Uno R3 stackable header _______ Digital: _____/ \__ Analog: ______________ ______________ txd ->-|D00 >RXD A5|- | \/ | rxd -<-|D01 -(D01)-|03 PD1/TXD PC3 26|-(A3)- -|D04 A1|- -(D02)-|04 PD2/INT0 PC2 25|-(A2)- -|D05~ A0|- -(D03)-|05 PD3/INT1/PWM PC1 24|-(A1)- -|D06~ | Power: -(D04)-|06 PD4 PC0 23|-(A0)- -|D07 Vin|- +5V ---|07 VCC GND 22|--- Gnd | GND|- Gnd ---|08 GND AREF 21|--- Vin -|D08 GND|- Xtal |X|--|09 PB6/OSC1 AVCC 20|--- +5V -|D09~ +5V|- 16MHz |X|--|10 PB7/OSC2 SCK/PB5 19|-(D13)- -|D10~ +3.3V|- -(D05)-|11 PD5/PWM MISO/PB4 18|-(D12)- -|D11~ Res|- -(D06)-|12 PD6/PWM PWM/MOSI/PB3 17|-(D11)- -|D12 IOREF|- -(D07)-|13 PD7 PWM/SS'/PB2 16|-(D10)- -|D13 LED --- | -(D08)-|14 PB0 PWM/PB1 15|-(D09)- -|GND | |______________________________| -|AREF | -|SCL | -|SDA | |________________| */