diff options
Diffstat (limited to 'Soft_UART_Timer1.h')
| -rw-r--r-- | Soft_UART_Timer1.h | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/Soft_UART_Timer1.h b/Soft_UART_Timer1.h new file mode 100644 index 0000000..4ad8669 --- /dev/null +++ b/Soft_UART_Timer1.h @@ -0,0 +1,115 @@ +/* + * Soft_UART_Timer1.h + * + * Software UART for ATmega328p using Timer1 + * + * Now only tranmission, no receiving + */ + +#ifndef SOFTUARTTIMER1_H_ +#define SOFTUARTTIMER1_H_ + +////////////////////////////////////////////////////////////////////////// +// Usage (in your .c file): +// 1. define Tx pin: DDR register, PORT register, PIN number: +// #define Soft_UART_TX_PORT PORTD +// #define Soft_UART_TX_DDR DDRD +// #define Soft_UART_TX_PIN 3 +// 2. define UART speed +// #define Soft_UART_Baud 9600 +// 3. include .h file: +// #include "Soft_UART_Timer1.h" +// 3. initialize software UART, required to call before usage other functions: +// static void Soft_UART_init(void); +// 4. send byte +// static void Soft_UART_send_byte(char byte); +// this function send byte in background, +// only one byte in background, other will wait. +////////////////////////////////////////////////////////////////////////// + + +////////////////////////////////////////////////////////////////////////// +// From this line begins code to the end of file. +// All code written in .h file for better inline optimization. +// Try to include this file only once per project. +////////////////////////////////////////////////////////////////////////// + +volatile char Soft_UART_busy_flag=0; +char Soft_UART_next_byte=0; + +////////////////////////////////////////////////////////////////////////// +// Initialization software UART, required to call before usage +////////////////////////////////////////////////////////////////////////// +static void Soft_UART_init(void) +{ // Pin init + bit_set(Soft_UART_TX_DDR,Soft_UART_TX_PIN); + bit_set(Soft_UART_TX_PORT,Soft_UART_TX_PIN); + // Timer1 init + TCCR1A=(0<<COM1A1)|(0<<COM1A0)|(0<<COM1B1)|(0<<COM1B0)|(1<<WGM11)|(0<<WGM10); + TCCR1B=(0<<ICNC1)|(0<<ICES1)|(1<<WGM13)|(1<<WGM12)|(0<<CS12)|(0<<CS11)|(0<<CS10); // prescaler 0, timer stopped + TCCR1C=(0<<FOC1A)|(0<<FOC1B); + TIMSK1=(0<<ICIE1)|(0<<OCIE1B)|(0<<OCIE1A)|(0<<TOIE1); + //ICR1=1666; + ICR1=F_CPU/Soft_UART_Baud; +} + +////////////////////////////////////////////////////////////////////////// +// Internal function, start timer, when need to send something +////////////////////////////////////////////////////////////////////////// +static void Soft_UART_Timer1_start(void) +{ + bit_set(TIMSK1,TOIE1); + bit_set(TCCR1B,CS10); +} + +////////////////////////////////////////////////////////////////////////// +// Internal function, stop timer, when nothing to send +////////////////////////////////////////////////////////////////////////// +static void Soft_UART_Timer1_stop(void) +{ + bit_clr(TIMSK1,TOIE1); + bit_clr(TCCR1B,CS10); +} + +////////////////////////////////////////////////////////////////////////// +// Send byte in background, only one byte in background, other - wait +////////////////////////////////////////////////////////////////////////// +static void Soft_UART_send_byte(char byte) +{ + while(Soft_UART_busy_flag) + ; + Soft_UART_busy_flag=1; + Soft_UART_Timer1_start(); + Soft_UART_next_byte=byte; +} + +////////////////////////////////////////////////////////////////////////// +// Internal function, send next bit +////////////////////////////////////////////////////////////////////////// +ISR(TIMER1_OVF_vect) +{ + static char Soft_UART_pos=0; + switch(Soft_UART_pos) + { + case 0: // send START bit + bit_clr(Soft_UART_TX_PORT,Soft_UART_TX_PIN); + break; + case 9: // send STOP bit + bit_set(Soft_UART_TX_PORT,Soft_UART_TX_PIN); + break; + case 10:// end of transmission + Soft_UART_busy_flag=0; + Soft_UART_pos=0; + Soft_UART_Timer1_stop(); + return; + default:// send data bit + if(bit_tst(Soft_UART_next_byte,Soft_UART_pos-1)) + bit_set(Soft_UART_TX_PORT,Soft_UART_TX_PIN); + else + bit_clr(Soft_UART_TX_PORT,Soft_UART_TX_PIN); + break; + } + Soft_UART_pos++; + bit_change(PORTB,5); +} +#endif /* SOFTUARTTIMER1_H_ */ |