// // ble.block.45.c // // software PWM servo motor hello-world, BLE communication // // Caroline Jaffe (adapted from Neil Gershenfeld) // December 2015 // // (c) Massachusetts Institute of Technology 2012 // This work may be reproduced, modified, distributed, // performed, and displayed for any purpose. Copyright is // retained and must be preserved. The work is provided // as is; no warranty is provided, and users accept all // liability. // #include #include #include #define output(directions,pin) (directions |= pin) // set port direction for output #define set(port,pin) (port |= pin) // set port pin #define clear(port,pin) (port &= (~pin)) // clear port pin #define pin_test(pins,pin) (pins & pin) // test for port pin #define bit_test(byte,bit) (byte & (1 << bit)) // test for bit set #define bit_delay_time 103 // bit delay for 9600 with overhead #define bit_delay() _delay_us(bit_delay_time) // RS232 bit delay #define half_bit_delay() _delay_us(bit_delay_time/2) // RS232 half bit delay #define char_delay() _delay_ms(10) // char delay #define serial_pins PINB #define serial_pin_in (1 << PB1) #define serial_pin_out (1 << PB2) #define output_port PORTB #define output_direction DDRB #define PWM_pin_0 (1 << PB0) #define loop_count 30 #define max_buffer 25 void get_char(volatile unsigned char *pins, unsigned char pin, char *rxbyte) { // // read character into rxbyte on pins pin // assumes line driver (inverts bits) // *rxbyte = 0; while (pin_test(*pins,pin)) // // wait for start bit // ; // // delay to middle of first data bit // half_bit_delay(); bit_delay(); // // unrolled loop to read data bits // if pin_test(*pins,pin) *rxbyte |= (1 << 0); else *rxbyte |= (0 << 0); bit_delay(); if pin_test(*pins,pin) *rxbyte |= (1 << 1); else *rxbyte |= (0 << 1); bit_delay(); if pin_test(*pins,pin) *rxbyte |= (1 << 2); else *rxbyte |= (0 << 2); bit_delay(); if pin_test(*pins,pin) *rxbyte |= (1 << 3); else *rxbyte |= (0 << 3); bit_delay(); if pin_test(*pins,pin) *rxbyte |= (1 << 4); else *rxbyte |= (0 << 4); bit_delay(); if pin_test(*pins,pin) *rxbyte |= (1 << 5); else *rxbyte |= (0 << 5); bit_delay(); if pin_test(*pins,pin) *rxbyte |= (1 << 6); else *rxbyte |= (0 << 6); bit_delay(); if pin_test(*pins,pin) *rxbyte |= (1 << 7); else *rxbyte |= (0 << 7); // // wait for stop bit // bit_delay(); half_bit_delay(); } void put_char(volatile unsigned char *port, unsigned char pin, char txchar) { // // send character in txchar on port pin // assumes line driver (inverts bits) // // start bit // clear(*port,pin); bit_delay(); // // unrolled loop to write data bits // if bit_test(txchar,0) set(*port,pin); else clear(*port,pin); bit_delay(); if bit_test(txchar,1) set(*port,pin); else clear(*port,pin); bit_delay(); if bit_test(txchar,2) set(*port,pin); else clear(*port,pin); bit_delay(); if bit_test(txchar,3) set(*port,pin); else clear(*port,pin); bit_delay(); if bit_test(txchar,4) set(*port,pin); else clear(*port,pin); bit_delay(); if bit_test(txchar,5) set(*port,pin); else clear(*port,pin); bit_delay(); if bit_test(txchar,6) set(*port,pin); else clear(*port,pin); bit_delay(); if bit_test(txchar,7) set(*port,pin); else clear(*port,pin); bit_delay(); // // stop bit // set(*port,pin); bit_delay(); // // char delay // bit_delay(); } void put_string(volatile unsigned char *port, unsigned char pin, char *str) { // // print a null-terminated string // static int index; index = 0; do { put_char(port, pin, str[index]); ++index; } while (str[index] != 0); } uint8_t turn_servo(uint8_t helper) { static int i; i = 0; // // 1 ms on time // if (helper == 1) { for (i = 0; i < loop_count; ++i) { set(output_port,PWM_pin_0); _delay_us(1000); clear(output_port,PWM_pin_0); _delay_us(19000); } return 0; } if (helper == 0) { for (i = 0; i < loop_count; ++i) { set(output_port,PWM_pin_0); _delay_us(2000); clear(output_port,PWM_pin_0); _delay_us(18000); } return 1; } return 1; } int main(void) { // // main // static char chr; static char buffer[max_buffer] = {0}; //static int index; static int helper; // // set clock divider to /1 // CLKPR = (1 << CLKPCE); CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0); // // initialize output pins // set(output_port, serial_pin_out); output(output_direction, serial_pin_out); clear(output_port, PWM_pin_0); output(output_direction, PWM_pin_0); // // main loop // //index = 0; helper = 0; while (1) { get_char(&serial_pins, serial_pin_in, &chr); if (chr == 'x') { helper = turn_servo(helper); } } }