lm75b

LM75B I²C temperature sensor with 0.125°C precision. Transition energy measurements include energy spent in the 10k pull-ups on SDA and SCL.

Configuration

VCC: 3.6 V
Shunt: 680 Ω
State duration: 250 ms
I²C: 4 kHz

Parameters

None

States

state	power
ACTIVE	332 µW (0.8%)
POWEROFF	7 µW (8.9%)

ACTIVE

Datasheet: The device is active and performing a temperature-to-digital conversion every 100 ms. The conversion takes about 10 ms. Afterwards, the temperature register is updated and the device becomes idle.

POWEROFF

Datasheet: The device is in powerdown mode. Temperature-to-digital conversion is halted; the I²C interface remains active.

Transitions

transition	duration	energy	rel. energy
getTemp	12740 µs (0.0%)	26016748 pJ (8.2%)	21722720 pJ (9.9%)
setHyst	9140 µs (0.0%)	22082226 pJ (9.8%)	19001499 pJ (11.4%)
setOS	9140 µs (0.0%)	21774238 pJ (9.9%)	18693283 pJ (11.7%)
shutdown	6980 µs (0.0%)	11808160 pJ (8.3%)	11746224 pJ (3.6%)
start	6980 µs (0.0%)	12445302 pJ (5.0%)	12391462 pJ (3.0%)

getTemp

float LM75::getTemp()
{
    sendBuf[0] = 0x00;
    i2c_data.sendCount = 1;
    i2c_data.recvCount = 2;
    sendRecv(&i2c_data);

    return recvBuf[0] + (recvBuf[1] / 256.0);
}

setHyst

void LM75::setHyst(unsigned char hyst)
{
    sendBuf[0] = 0x02;
    sendBuf[1] = hyst;
    sendBuf[2] = 0;
    i2c_data.sendCount = 3;
    i2c_data.recvCount = 0;
    sendRecv(&i2c_data);
}

setOS

void LM75::setOS(unsigned char os)
{
    sendBuf[0] = 0x03;
    sendBuf[1] = os;
    sendBuf[2] = 0;
    i2c_data.sendCount = 3;
    i2c_data.recvCount = 0;
    sendRecv(&i2c_data);
}

shutdown

void LM75::shutdown()
{
    sendBuf[0] = 0x01;
    sendBuf[1] = 0x01;
    i2c_data.sendCount = 2;
    i2c_data.recvCount = 0;
    sendRecv(&i2c_data);
}

start

void LM75::start()
{
    sendBuf[0] = 0x01;
    sendBuf[1] = 0x00;
    i2c_data.sendCount = 2;
    i2c_data.recvCount = 0;
    sendRecv(&i2c_data);
}