Where can i find information about the exact position off the Hall-element in the SOT23- or DFN-package?

Kind regards

I was just playing around with the si7057 and wrote functions for reading electronic ID and Temperature and also wanted to check the returned CRCs. At first I was quite confused, because whatever I tried, I never got the correct crc calculated. In the datasheet an initial value of 0xfc is given.

Then I tried different initial values and found out, that for EID a initial value of 0x00 must be used to get the correct CRC.

  uint8_t rxBuf[8];
  uint8_t crcCalc[6] = { 0 };
  uint8_t crcRead[6] = { 0 };

  // SNA
  SI705Y_Cmd(SI705Y_READ_ID1, 2, rxBuf, 8);

  crcRead[0] = rxBuf[1];
  crcRead[1] = rxBuf[3];
  crcRead[2] = rxBuf[5];
  crcRead[3] = rxBuf[7];

  crcCalc[0] = Crc8_add(rxBuf[0], crcCalc[0]);
  crcCalc[1] = Crc8_add(rxBuf[2], crcCalc[0]);
  crcCalc[2] = Crc8_add(rxBuf[4], crcCalc[1]);
  crcCalc[3] = Crc8_add(rxBuf[6], crcCalc[2]);

  // SNB
  SI705Y_Cmd(SI705Y_READ_ID2, 2, rxBuf, 6);

  crcRead[4] = rxBuf[2];
  crcRead[5] = rxBuf[5];

  crcCalc[4] = Crc8(rxBuf + 0, 2, crcCalc[4]);
  crcCalc[5] = Crc8(rxBuf + 3, 2, crcCalc[4]);

But when I want to read the temperautre and have the crc checked, I need to use a initial value of 0xff.

  uint8_t rxBuf[3];
  uint8_t crcRead;
  uint8_t crcCalc;

  SI705Y_Cmd(0, 0, rxBuf, 3);
  crcRead = rxBuf[2];
  crcCalc = Crc8(rxBuf, 2, 0xff);

/**
 * add a single byte to crc calculation.
 *
 * @param data byte to add to crc calc.
 * @param crc previous crc value
 * @return calculated crc value
 */
static uint8_t Crc8_add(uint8_t data, uint8_t crc)
{
  crc ^= data;
  for (int8_t j = 8u; j > 0u; j--)
  {
    if (crc & 0x80u)
      crc = (crc << 1u) ^ 0x131u;
    else
      crc = (crc << 1u);
  }
  return crc;
}

/**
 * Calculate CRC of temperature sensor data.
 * According to si7057, the initial value has to be set to
 * 0xfc.
 * Although, to get a correct crc calculation for measurements,
 * the initial has to be set to 0xff.
 * For ElectronicID reads, the initial has to be 0x00.
 *
 * @param data bytes to calculate crc over
 * @param length amount of bytes in data buffer
 * @param crc initial value for crc
 * @return calculated crc value
 */
static uint8_t Crc8(uint8_t *data, uint8_t length, uint8_t crc)
{
  uint8_t i;

  for (i = 0; i < length; i++)
    crc = Crc8_add(data[i], crc);

  return crc;
}

I hope, this will help someone.

This is my first time using the Si7210.  I initially set up the sensor to take single readings; after noticing the noise variation I decided to implement multiple samples in burst mode.  I have tried to implement 64 samples per burst, one burst per reading.  The sensor stays awake the whole time.  Over 100 samples the single-shot average is about 0.12mT higher than the burst mode.   This isn't a very significant value, but it is consistent and has me wondering 'why?'. 

Any thoughts? 

Hello,

We are planning to use SI1153-AA9X-GMR LGA Module in one of our application. Need to know if I can connect 3 such devices to same I2C master directly.

Not able to figure out 3 slave device address from datasheet. We will using only 1 LED channel per module.

Thanks and Regards

Myke

 In order to mount Si 7021 in our product, we are evaluating its performance.
 Please let me ask a few questions about the RH evaluation details.
 
 Q1.About reference sample
 　I plan to use SI7021-EB(w/ Si7013USB-DONGLE) as the reference sample.
   Is the 3% error described in the specification guaranteed?
 
 Q2.humidity variation error
    7021 was mounted on a prototype board, and the humidity was measured with it.
    By measuring 5 samples, the worst error was -8% RH at a target RH value of 50% (at 25 degrees).
    When we made the prototype board, we had complied with "AN 607, Design and Bring-Up  Checklist in section 3.5".
    What is the cause of the variation in RH error?

 3.How to use the heater
   We want to test at a RH above 80%, and I think heater is needed in this condition according to the following URL.
   <https://www.silabs.com/community/sensors/forum.topic.html/when_si7021_is_neede-8a2a>
  
   Can you tell me the required time for the heater to operate at different current conditions?
 　HEATER 0b0000(3.09mA) -> ?? sec
   HEATER 0x1111(94.20mA) -> ??? sec

   Thanks in advance! I am looking forward to your reply.

Hi,
Our lab is considering to adopt the sensor to the next project in order to get UV Index. Accoding to the document(https://cdn-shop.adafruit.com/datasheets/Si1145-46-47.pdf), the sensor can output UV Index.
Although UV Index strongly depends on the sensor's spectral sensitivity, we found only a chart which shows the spectral sensitivity of each diodes. We guess the sensor estimates UV Index by using these diodes.
But the document does not articulate how does the UV Index calculate.
We need more information about the sensor spectral sensitivity to guarantee the UV Index value is correct.

So, please give some spectral sensitivity charts of the sensor.

Thank you in advance!

Hello,

I'm using the SI 1102 for proximity detection in a floor based application. The sensor is not isolated from the source and is behind a ~.5" thick quartz window; the window is ~.5" away from sensor / source pair.

If the room light is low or dark the sensors tend to throw false positives and if we turn the lights back on the behavior improves. We are trying to improve performance in low light. 

Also what is the root cause of this? It seems counter intuitive as you would think light sources would increase the chances of false positives not reduce them.

We have deployed a product in the last year or so that uses the si7021.  We have shipped about 12k units in this time.  Recently a customer contacted us reporting that at their installation all five of our devices were reporting exactly 83C in a 5C environment.  I could hardly believe this was the case so I had the units returned.  To my surprise  they are indeed reporting 83C, in my case I am at my desk where it is about 24C.

I can read back the electronic serial numbers and firmware from the device.  Also the humidity values are changing, but the temperature is stuck at 83C.

I attached a trace of the IIC communications.  You will see the temperature code being sent back is 0xBD34 which when converted equals 83.02021C. 

What could be going on here?

We are using an Si7005 in a dry nitrogen atmosphere.  The sensor is in a 125 liter sealed metal box being purged with nitrogen (99.998% pure Nitrogen, claimed H2O concentration is < 3ppm) from a liquid dewar.  The %RH is about -3 from the sensor after a week and seems to be moving downward even more as time passes. 

Is the sensor drifting downward because of the extended exposure to very low humidity, or is it giving the correct answer and the box it is drying out?

Are any of your sensors made for low/very low humidity environments?

As per datasheet of Si7051 temp sensor, it is I2C base, and there is a address of it shown in datasheet is 0x40. 

So suppose in my application if I want to use 2 of these sensor having connected on single I2C bus, how can my Master (MCU) will send address, ? can't I use this sensor in 2 nos. on single I2C bus ?  how to set dynamic address on this Si7051 sensor ?

Hello ,

       Si1133/si115x optical sensors evalution board rev2.0 not working with my host device in 5 five sensors board,in that through SW1  using Long Range PROX sensor after parameters set values getting only one value ()repeating every time not update adc raw value    please kindly help me.

sample code:

             HAL_Delay(10);
            HAL_Delay(10);
            HAL_Delay(10);
            Ir_reset= 0x01;
          HAL_I2C_Mem_Write(&hi2c1, 0xA6,  0x0B, I2C_MEMADD_SIZE_8BIT, &Ir_reset, 1, 10);
            HAL_Delay(10);

      uint8_t packet[2];
            packet[0] = 0x0A;
      packet[1] = 0x3f;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer,1,1000);
            packet[0] = 0x0B;
      packet[1] = 0x9F;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer,1,1000);
            
            
            uint8_t packet1[2];
            packet1[0] = 0x0A;
      packet1[1] = 0x01;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet1, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer1,1,1000);
            packet1[0] = 0x0B;
      packet1[1] = 0x81;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet1, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer1,1,1000);
            
            uint8_t packet2[2];
            packet2[0] = 0x0A;
      packet2[1] = 0x62;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet2, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer2,1,1000);
            packet2[0] = 0x0B;
      packet2[1] = 0x82;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet2, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer2,1,1000);
         
          uint8_t packet3[2];
            packet3[0] = 0x0A;
      packet3[1] = 0x04;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet3, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer3,1,1000);
            packet3[0] = 0x0B;
      packet3[1] = 0x83;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet3, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer3,1,1000);
            
            uint8_t packet4[2];
            packet4[0] = 0x0A;
      packet4[1] = 0x61;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet4, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer4,1,1000);
            packet4[0] = 0x0B;
      packet4[1] = 0x85;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet4, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer4,1,1000);
            
            uint8_t packet5[2];
            packet5[0] = 0x0A;
      packet5[1] = 0x62;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet5, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer5,1,1000);
            packet5[0] = 0x0B;
      packet5[1] = 0x86;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet5, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer5,1,1000);
            
            uint8_t packet6[2];
            packet6[0] = 0x0A;
      packet6[1] = 0x06;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet6, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer6,1,1000);
            packet6[0] = 0x0B;
      packet6[1] = 0x87;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet6, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer6,1,1000);
            
            uint8_t packet7[2];
            packet7[0] = 0x0A;
      packet7[1] = 0x08;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet7, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer7,1,1000);
            packet7[0] = 0x0B;
      packet7[1] = 0x88;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet7, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer7,1,1000);
            
          uint8_t packet8[2];
            packet8[0] = 0x0A;
      packet8[1] = 0x40;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet8, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer8,1,1000);
            packet8[0] = 0x0B;
      packet8[1] = 0x89;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet8, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer8,1,1000);
            
            uint8_t packet9[2];
            packet9[0] = 0x0A;
      packet9[1] = 0x01;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet9, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer9,1,1000);
            packet9[0] = 0x0B;
      packet9[1] = 0x9B;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet9, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer9,1,1000);
            
            uint8_t packet10[2];
            packet10[0] = 0x0A;
      packet10[1] = 0x00;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet10, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer10,1,1000);
            packet10[0] = 0x0B;
      packet10[1] = 0x9A;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet10, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer10,1,1000);
            
            uint8_t packet11[2];
            packet11[0] = 0x0A;
      packet11[1] = 0x05;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet11, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer11,1,1000);
            packet11[0] = 0x0B;
      packet11[1] = 0x9C;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet11, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer11,1,1000);
            
            uint8_t packet12[2];
            packet12[0] = 0x0A;
      packet12[1] = 0x10;
        HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet12, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer12,1,1000);
            packet12[0] = 0x0B;
      packet12[1] = 0x9D;
            HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0A, I2C_MEMADD_SIZE_8BIT, packet12, 2, 1000);
            HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x11,I2C_MEMADD_SIZE_8BIT,&ir_buffer12,1,1000); 

            Ir_int_status = 0x01;        
           HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x12, I2C_MEMADD_SIZE_8BIT, &Ir_int_status, 1, 10);
            
            Ir_int_enable = 0x03;        
           HAL_I2C_Mem_Write(&hi2c1, 0xA6 ,0x0F, I2C_MEMADD_SIZE_8BIT, &Ir_int_enable, 1, 10);
        

      start_cmd= 0x13;
          HAL_I2C_Mem_Write(&hi2c1, 0xA6,  0x0B, I2C_MEMADD_SIZE_8BIT, &start_cmd, 1, 10);

while(1){

HAL_I2C_Mem_Read(&hi2c1, 0xA7,0x12,I2C_MEMADD_SIZE_8BIT,raw_buffer,5,1000);}

IR SENSOR RAW VALUE:4088
IR SENSOR RAW VALUE:4088
IR SENSOR RAW VALUE:4088
IR SENSOR RAW VALUE:4088

Thanks & Regards,

hari.

I'm trying to tune in an application using the Si1153.

I was wondering what the difference is between adjusting the ADC decimation rate in ADCCONFIGx and adjusting the hardware gain in ADCSENx. It seems to me that both directly affect the integration time of the ADC which causes changes in gain.

So, the question becomes, is DECIM_TIME = 48.8 µs and HW_GAIN = 0 equivalent to DECIM_TIME = 24.4 µs and HW_GAIN = 1? I would love to hear if one or the other might have a positive effect on reducing noise or missed codes.