int8_t ow_temp_power(ow_rom_code_t *rom)
{
#if ONEWIRE_BUSCOUNT > 1
uint8_t busmask = 1 << (ONEWIRE_STARTPIN); // FIXME: currently only on 1st bus
#else
uint8_t busmask = ONEWIRE_BUSMASK;
#endif
int8_t ret;
if (rom == NULL)
ret = ow_skip_rom();
else {
if (!ow_temp_sensor(rom))
return -2;
ret = ow_match_rom(rom);
}
if (ret < 0)
return ret;
/* transmit command byte */
ow_write_byte(busmask, OW_FUNC_READ_POWER);
return (int8_t)(ow_read(busmask));
}
static void ds18b20_start(void)
{
ow_reset();
ow_skip_rom();
ow_write_byte(DS18B20_CMD_CONVERT_T);
}
int8_t ow_eeprom_read(ow_rom_code_t *rom, void *data)
{
#if ONEWIRE_BUSCOUNT > 1
uint8_t busmask = 1 << (ONEWIRE_STARTPIN); // FIXME: currently only on 1st bus
#else
uint8_t busmask = ONEWIRE_BUSMASK;
#endif
int8_t ret;
if (rom == NULL)
ret = ow_skip_rom();
else {
/* check for known family code */
if (!(rom->family == OW_FAMILY_DS2502E48))
return -2;
ret = ow_match_rom(rom);
}
if (ret < 0)
return ret;
/* transmit command byte */
ow_write_byte(busmask, OW_FUNC_READ_MEMORY);
/* transmit address (mac address starts at offset 5 */
ow_write_byte(busmask, 5);
ow_write_byte(busmask, 0);
/* read back crc sum of the command */
uint8_t crc = ow_read_byte(busmask);
/* check crc */
uint8_t crc2 = 0;
crc2 = _crc_ibutton_update(crc2, OW_FUNC_READ_MEMORY);
crc2 = _crc_ibutton_update(crc2, 5);
crc2 = _crc_ibutton_update(crc2, 0);
if (crc != crc2)
return -2;
uint8_t *p = (uint8_t *)data+5;
/* read 6 byte of data */
for (uint8_t i = 0; i < 6; i++)
*p-- = ow_read_byte(busmask);
return 0;
}
int8_t ow_temp_read_scratchpad(ow_rom_code_t *rom, ow_temp_scratchpad_t *scratchpad)
{
uint8_t busmask;
int8_t ret;
if (rom == NULL)
ret = ow_skip_rom();
else {
/* check for known family code */
if (!ow_temp_sensor(rom))
return -3;
ret = ow_match_rom(rom);
}
if (ret < 0)
return ret;
/* transmit command byte */
ow_write_byte(ONEWIRE_BUSMASK, OW_FUNC_READ_SP);
#if ONEWIRE_BUSCOUNT > 1
for (uint8_t bus = 0; bus < ONEWIRE_BUSCOUNT; bus++) {
/* read 9 bytes from each onewire bus */
busmask = (uint8_t)(1 << (bus + ONEWIRE_STARTPIN));
#else
busmask = ONEWIRE_BUSMASK;
#endif
for (uint8_t i = 0; i < 9; i++) {
scratchpad->bytewise[i] = ow_read_byte(busmask);
}
/* check CRC (last byte) */
if (scratchpad->crc == crc_checksum(&scratchpad->bytewise, 8)) {
/* return if we got a valid response from one device */
return 1;
}
#if ONEWIRE_BUSCOUNT > 1
}
#endif
return -2;
}
int8_t ow_temp_start_convert(ow_rom_code_t *rom, uint8_t wait)
{
int8_t ret;
if (rom == NULL)
ret = ow_skip_rom();
else {
/* check for known family code */
if (!ow_temp_sensor(rom))
return -2;
ret = ow_match_rom(rom);
}
if (ret < 0)
return ret;
/* transmit command byte */
ow_write_byte(ONEWIRE_BUSMASK, OW_FUNC_CONVERT);
OW_CONFIG_OUTPUT(ONEWIRE_BUSMASK);
OW_HIGH(ONEWIRE_BUSMASK);
if (!wait)
return 0;
_delay_ms(800); /* The specification say, that we have to wait at
least 500ms in parasite mode to wait for the
end of the conversion. 800ms works more reliably */
while(!ow_read(ONEWIRE_BUSMASK));
return 1;
}
