I've been trying to get a simple loop back program working on my tiny 2313 devel board from optimal. Its got the onboard max 232 chip, and i've hooked Rx to PD1 and Tx to PD0.
I've been folding the example code from http://www.pek.nu/pekproj/proj/el/avrex/tiny2313_uart_ex.c
to try to put a character on my LCD and send a char back to the PC
I;ve been using Br@ys terminal to send characters to the tiny 2313 at 19200, 8-bits + 1 stop bit, no parity, no handshacking; regardless of what i send the avr it sends either 80 or 00 back; on the LCD i seem to always get a box.
code as follows
//HD44780 lcd controller //PORTB is the data bus //PD4 is the R/S line //PD5 is the R/W line //PD6 is the Enable line // // UART //PD0 and PD1 are Rx and Tx #include#include #include #include #ifndef BYTE #define BYTE unsigned char #endif register BYTE data asm("r16"); BYTE data_dirty; void init_hd44780_8bit(void); void init_uart(void); void send_uart(BYTE c); void send_string(unsigned char *text); void send_char(char d); void send_cmd(char c); void send_cls(void); void set_line(char l); void toggle_enable(void); //confiqure the uart registers void init_uart(void) { // Initiate UART UBRRH = 0; // 19200 bps at 8 MHz UBRRL = 25; UCSRB = _BV(RXEN) | _BV(TXEN) | _BV(RXCIE); // Rx Complete Interrupt & Enable Rx/Tx UCSRC = _BV(UCSZ1) | _BV(UCSZ0); // 8N1 } //initialized the ports and starts communitation with the lcd void init_hd44780_8bit(void) { DDRB = DDRB | 0xFF; //set up data pins PORTB = 0x00; DDRD = DDRD | 0x70; //set up control pins PORTD = 0x40; _delay_ms(15); send_cmd(0x30); _delay_ms(5); send_cmd(0x30); _delay_us(160); send_cmd(0x30); _delay_us(160); //cranking the engine send_cmd(0x3C); //function set _delay_ms(2); send_cmd(0x08); //display off _delay_ms(2); send_cmd(0x01); //clear display _delay_ms(1); send_cmd(0x06); //cursor move setting _delay_ms(1); send_cmd(0x0C); //display on _delay_ms(1); } // function to send a single char to the display void send_char(char d) { PORTD = 0x50; //make enable and RS high PORTB = d; toggle_enable(); PORTB = 0x00; } //function to send a command to the display void send_cmd(char c) { PORTD = 0x40; //makes sure enable is high PORTB = c; toggle_enable(); PORTB = 0x00; } // sends a string of chars to the display void send_string(unsigned char *text) { char cnt = 0; while(*text) { cnt ++; if( cnt == 21) set_line(2); if( cnt == 41) set_line(3); if( cnt == 61) set_line(4); send_char(*text++); } } //clears the display void send_cls(void) { send_cmd(0x01); } //sets the active lie void set_line(char l) { char tmp = 0; if (l == 4) tmp = 0x54; if (l == 3) tmp = 0x14; if (l == 2) tmp = 0x40; if (l == 1) tmp = 0x00; send_cmd(0x80 | tmp); } //toggles the endable bit void toggle_enable(void) { PORTD = PORTD & 0x00; //toggle enable _delay_us(5); PORTD = PORTD | 0x40; _delay_us(5); } SIGNAL(SIG_USART0_RX) { data = UDR; // Store received byte data_dirty = 1; } int main (void) { init_hd44780_8bit(); init_uart(); send_string("Hello"); data_dirty = 0; sei(); // Enable global interrupts while(1) { if (data_dirty == 1) { send_char(data); send_uart(data); data_dirty = 0; } } return 1; } void send_uart(BYTE c) { while(!(UCSRA & (1<<UDRE))); // Wait for empty transmit buffer UDR = c; asm volatile ("out 0x0c,r16\n\t"); }
