twr_onewire_relay.c

#include <twr_gpio.h>
#include <twr_onewire_relay.h>
 
bool _twr_onewire_relay_read_state(twr_onewire_relay_t *self);
 
bool twr_onewire_relay_init(twr_onewire_relay_t *self, twr_onewire_t *onewire, uint64_t device_number)
{
    memset(self, 0, sizeof(*self));
    self->_device_number = device_number;
    self->_onewire = onewire;
 
    if (!_twr_onewire_relay_read_state(self))
    {
        return false;
    }
 
    return true;
}
 
bool twr_onewire_relay_set_state(twr_onewire_relay_t *self, twr_onewire_relay_channel_t relay_channel, bool state)
{
    if (!self->_state_valid && !_twr_onewire_relay_read_state(self))
    {
        return false;
    }
 
    if (!twr_onewire_reset(self->_onewire))
    {
        return false;
    }
 
    uint8_t new_state = self->_state;
 
    if (!state)
    {
        new_state |= (1 << relay_channel);
    }
    else
    {
        new_state &= ~(1 << relay_channel);
    }
 
    twr_onewire_select(self->_onewire, &self->_device_number);
 
    uint8_t buffer[] = { 0x5A, new_state, ~new_state };
 
    twr_onewire_write(self->_onewire, buffer, sizeof(buffer));
 
    if (twr_onewire_read_byte(self->_onewire) != 0xAA)
    {
        return false;
    }
 
    if (twr_onewire_read_byte(self->_onewire) != new_state)
    {
        return false;
    }
 
    self->_state = new_state;
 
    return true;
}
 
bool twr_onewire_relay_get_state(twr_onewire_relay_t *self, twr_onewire_relay_channel_t relay_channel, bool *state)
{
    if (!self->_state_valid)
    {
        return false;
    }
 
    *state = ((self->_state >> relay_channel) & 0x01) == 0x00;
 
    return true;
}
 
bool _twr_onewire_relay_read_state(twr_onewire_relay_t *self)
{
    self->_state_valid = false;
 
    if (!twr_onewire_reset(self->_onewire))
    {
        return false;
    }
 
    twr_onewire_select(self->_onewire, &self->_device_number);
 
    twr_onewire_write_byte(self->_onewire, 0xF5);
 
    self->_state = twr_onewire_read_byte(self->_onewire);
 
    self->_state_valid = true;
 
    return true;
}