void main(void) {
// one wire bus
struct soft_ow sow_ctx;
// temperature reading
uint16_t temperature = 0x00;
// configure the bus
sow_ctx.conf = SOFT_OW_CONF_MAKE(OW_POWER_PARASITE, OW_SINGLEDROP);
sow_ctx.bus.port = &OW_PORT;
sow_ctx.bus.pin = OW_PIN;
// initialize one-wire
sow_init(&sow_ctx);
// perform HW init 12 bit resolution
ds18b20_write_rom(&sow_ctx, NULL, 0x00, 0x00, 0x03, 0x00);
// execution loop
for (;;) {
// start conversion
ds18b20_start_conversion(&sow_ctx, NULL);
// wait for the conversion to finnish
_delay_ms(800);
// read the temperature
ds18b20_read_scratchpad(&sow_ctx,
NULL,
(uint8_t *)&temperature, 2);
}
}
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(ds18b20_poll_process, ev, data)
{
static struct etimer et;
static uint8_t scratchpad[DS18B20_SCRATCHPAD_SIZE];
static ow_rom_code_t id;
PROCESS_BEGIN();
printf("\nDS18B20 test\n");
printf("VSEC ON\n");
power_control_vsec_set(1);
/* initialize the DS18B20 hardware */
printf("Initialize 1-wire\n");
ow_init();
printf("1-wire READ ROM\n");
id = ow_read_rom();
printf("Initialize DS18B20\n");
ds18b20_init();
printf("DS18B20 init done\n");
/* Poll at 1Hz */
etimer_set(&et, CLOCK_SECOND);
while(1) {
PROCESS_WAIT_EVENT_UNTIL(etimer_expired(&et));
/* Reset the etimer to trig again */
etimer_reset(&et);
ds18b20_read_scratchpad(id, scratchpad);
ds18b20_convert_temperature(id);
}
PROCESS_END();
}
void ds18b20_write_rom(volatile struct soft_ow *a_bus, ow_romcode_t *a_romcode, uint8_t a_th, uint8_t a_tl, uint8_t a_res, uint8_t a_force) {
uint8_t tmp[5] = { 0x00 };
if (NULL == a_romcode ||
OW_SINGLEDROP == SOFT_OW_TOPOLOGY_GET(a_bus->conf)) {
if (!a_force) {
// first read ROM and check if the configuration register
// is not already set to the requested value
ds18b20_read_scratchpad(a_bus, a_romcode, tmp, sizeof(tmp));
}
// build the configuration value
tmp[0] = a_th;
tmp[1] = a_tl;
tmp[2] = ((a_res & 0x03) << 5) | 0x1f;
// write only if configuration register differs or force has been
// requested
if (tmp[4] != tmp[2] || a_force) {
sow_reset(a_bus);
sow_write_byte(a_bus, OWN_SKIP_ROM);
sow_write_byte(a_bus, DS18B20_CMD_WRITE_SP);
// save to eeprom
for (uint8_t len = 0; len < 3; len++)
sow_write_byte(a_bus, tmp[len]);
// persistently store in rom
sow_reset(a_bus);
sow_write_byte(a_bus, OWN_SKIP_ROM);
sow_write_byte(a_bus, DS18B20_CMD_COPY_SP);
}
}
}