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#include <avr/io.h>
#include <util/delay.h>
#include "bridge.h"
/* port D
*
* 4 1- (NMOS, inverted)
* 5 1+ (PMOS)
* 6 2- (NMOS, inverted)
* 7 2+ (PMOS)
*
*/
#define D_1_MINUS (1 << 4)
#define D_1_PLUS (1 << 5)
#define D_2_MINUS (1 << 6)
#define D_2_PLUS (1 << 7)
enum bridge_state {
BRIDGE_OFF,
BRIDGE_HEATING,
BRIDGE_COOLING
};
static enum bridge_state bridge_state;
/* Turns the H-bridge off, putting the output
* into high impedance mode. */
void bridge_off(void)
{
if (bridge_state == BRIDGE_OFF)
return;
PORTD |= D_1_MINUS | D_2_MINUS;
PORTD &= ~(D_1_PLUS | D_2_PLUS);
_delay_ms(100);
bridge_state = BRIDGE_OFF;
}
/* Turns the H-bridge on, setting 1+ 2- */
void bridge_on_heat(void)
{
if (bridge_state == BRIDGE_HEATING)
return;
bridge_off();
bridge_state = BRIDGE_HEATING;
PORTD |= D_1_PLUS;
PORTD &= ~D_2_MINUS;
}
/* Turns the H-bridge on, setting 1- 2+ */
void bridge_on_cool(void)
{
if (bridge_state == BRIDGE_COOLING)
return;
bridge_off();
bridge_state = BRIDGE_COOLING;
PORTD |= D_2_PLUS;
PORTD &= ~D_1_MINUS;
}
/* Initializes the output port needed for the H-bridge */
void bridge_init(void)
{
PORTD |= D_1_MINUS | D_2_MINUS;
PORTD &= ~(D_1_PLUS | D_2_PLUS);
DDRD |= D_1_PLUS | D_1_MINUS | D_2_PLUS | D_2_MINUS;
bridge_state = BRIDGE_OFF;
}
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