There are ~30 Knowledge Base Articles (KBAs) in the Sensors section of the forum covering multiple sensors products. Sometimes, it's difficult to search for the information that you're interested in, especially when you don't know if that exists or not.
To simplify this task we have created a Sensors Knowledge Base Article List which has all the KBAs divided into sub-topics. This list only contains KBAs which are meaningful today, so you won't find anything related to legacy products. This is to avoid confusing our customers into reading material which is no longer applicable.
Can you explain the notation in the datasheet in the "operation" column of the ADCMUX row of the table for the ADCCONFIGx parameter? The notation uses for example "D + 10" for the UV "optical function." But the term "D" has no antecedent anywhere in the datasheet, as far as I know.
I assume "D" refers to a separate diode for UV.
Does the "+10" mean that the mcu on the chip adds ten to some raw result?
Also, what is the interpretation of a negative result? That the dark current is less than the light current (where you are measuring the diode in two ways, dark current and light current, and taking the difference) ?
Related to my other post about detecting daylight using UV indoors.
SI7020 is sitting on our board, it is directly powered by 3.3V coming from X-NUCLEO-LPM01A (directly connected to GND and VDD of SI7020, no any other current flow path).
Software:
I am running STM32-CUBEMONITOR-POWER PC utility connected to X-NUCLEO-LPM01A, MCU of my board is not talking to SI7020 (no I2C communication, MCU is not powered, just SI7020 is powered).
Question:
Why SI7020 consuming that much power in standby mode?
I believe SI7020 must be in standby mode, correct? Or, Is there any command to send that in standby mode (I didn't find any such command in the datasheet)?
My application is: detect day versus night, indoors, in a room with south facing windows. I am exploring the Si1133 to measure UVA. I can put the detector within 10 feet of the windows, high and facing down so the detector gets reflected UV, and never gets direct sunlight, and gets only reflected artificial lights from typical room lighting of about 400 lux white, fluorescent light. My understanding is the window glass will transmit about 50% of UVA, that the sky will scatter significant UVA, that night sky has no UVA, and that artificial lights produce negligible UVA.
Might that work? Do you have any suggestions re diffuser, physical filters, parameters of the Si1133, and which set of diodes to use? My plan is to read only the UV diode.
I want to estimate sun time by detecting sundown and sunset, despite noise from artificial lights. I don't need accuracy. I plan to take samples over many days. I understand that the weather and season will have an effect.
We are using a Si1133 chip on a board with a STM32L4 MCU. We have ported the code available at https://siliconlabs.github.io/Gecko_SDK_Doc/efm32pg12/html/si1133_8c_source.html, and we are able to measure the lux and UVI (still not tested for accuracy). We want to be able to configure the Si1133 to generate an interrupt if there is a sudden light level change (increase), is it possible this kind of application using this chip? My doubt is because if we enable the IRQ we will be interrupted on each light measurement end, we are not able to configure it to interrupt the CPU only when the threshold level is exceeded, or am I missing some alternative configuration? To be able to detect autonomously a sudden high light level it should be running in autonomous mode, so it will interrupt the MCU at the end of each measurement cycle, right?
For a research project, I am currently trying to read the acceleration data from the BMA280. At this moment I'm following a complete procedure to initialize the accelerometer. (found on the internet, I wrote the code myself). https://9apps.ooo/I use the code found on this forum to read and write the registers of the accelerometer.
Perform self test
Check if difference from read out of +X en -X is bigger than 800mg (answer: check)
Check if difference from read out of +Y en -Y is bigger than 800mg (answer: check)
Check if difference from read out of +Z en -Z is bigger than 400mg (answer: check)
Soft reset the accelerometer
wait 1,5 sec
Initialize the accelerometer to my preferences
Perform Fast compensation
Clear offset register
Set offset compensation to X: 0g, Y: 0g, Z:+1g, BW 1%
X-axis calibration
Y-axis calibration
Z-axis calibration
Read offset X my answer: x = -31 mg
Read offset Y my answer: y = -15 mg
Read offset Z my answer: z = 0 mg
init done
The values afterwards are x=+-20mg, y=+-2mg en z=+- -19mg. I expected the values would be x=+-0g, y=+-0g en z=+- -1g when the chip is laying flat on my desk.
I convert the acceleration data in this way.
Can somebody confirm me If this is correct? Or give me the correct init from the accelerometer?
We are using an Si7057 in our device to measure the temperature. However we observed an offset between 0.2 and 0.4 degrees compared to older devices in the same environment. The temperature range observed is between 25 and 40 degrees and the offset seems to remain fairly constant. We observed the offset in 30 sensors so far. We are looking for an explanation, but we could not find any.
We checked the decoding of the temperature code, but we could not find an error. We use the following C code to compute the temperature:
Unless I am mistaken, our implementation conforms almost exactly to the specification in the data sheet. Is this implementation correct?
Could this in any way be explained by measurement errors/device variability of the sensors themselves? +.3 degrees would be just within the specification, but for calibrated sensors we expected a somewhat more random distribution across devices and values roughly centered around 0.
/***************************************************************************//**
* @file
* @brief Relative humidity and temperature sensor demo for SLSTK3402A
*******************************************************************************
* # License
* <b>Copyright 2018 Silicon Laboratories Inc. www.silabs.com</b>
*******************************************************************************
*
* The licensor of this software is Silicon Laboratories Inc. Your use of this
* software is governed by the terms of Silicon Labs Master Software License
* Agreement (MSLA) available at
* www.silabs.com/about-us/legal/master-software-license-agreement. This
* software is distributed to you in Source Code format and is governed by the
* sections of the MSLA applicable to Source Code.
*
******************************************************************************/
#include "em_device.h"
#include "em_chip.h"
#include "em_cmu.h"
#include "em_emu.h"
#include "em_gpio.h"
#include "cpt112s_config.h"
#include "i2cspm.h"
#include "si7013.h"
#include "sl_sleeptimer.h"
#include "graphics.h"
#include "em_adc.h"
#include "bspconfig.h"
/***************************************************************************//**
* Local defines
******************************************************************************/
/** Time (in ms) between periodic updates of the measurements. */
#define MEASUREMENT_INTERVAL_MS 2000
/***************************************************************************//**
* Local variables
******************************************************************************/
/* Variables used by the display callback. */
static void (*mem_lcd_callback_func)(void*) = 0;
static void *mem_lcd_callback_arg = 0;
/** This flag tracks if we need to update the display
* (animations or measurements). */
static volatile bool updateDisplay = true;
/** This flag tracks if we need to perform a new
* measurement. */
static volatile bool updateMeasurement = true;
/** This flag indicates that a new measurement shall be done. */
static volatile bool measurement_flag = true;
/** Timer used for periodic update of the measurements. */
static sl_sleeptimer_timer_handle_t measurement_timer;
/** Timer used for periodic maintenance of the display. */
static sl_sleeptimer_timer_handle_t display_timer;
/***************************************************************************//**
* @brief Setup GPIO, enable sensor isolation switch
*****************************************************************************/
static void gpioSetup(void)
{
/* Enable GPIO clock */
CMU_ClockEnable(cmuClock_GPIO, true);
/* Enable Si7021 sensor isolation switch */
GPIO_PinModeSet(CS0_SENSOR_EN_PORT, CS0_SENSOR_EN_PIN, gpioModePushPull, 1);
}
/***************************************************************************//**
* @brief Helper function to perform data measurements.
******************************************************************************/
static void measure_humidity_and_temperature(I2C_TypeDef *i2c, uint32_t *rhData, int32_t *tData)
{
Si7013_MeasureRHAndTemp(i2c, SI7021_ADDR, rhData, tData);
}
/***************************************************************************//**
* @brief Callback from timer
******************************************************************************/
static void measurement_callback(sl_sleeptimer_timer_handle_t *handle, void *data)
{
(void)handle;
(void)data;
measurement_flag = true;
}
/***************************************************************************//**
* @brief Main function
******************************************************************************/
int main(void)
{
I2CSPM_Init_TypeDef i2cInit = I2CSPM_INIT_DEFAULT;
EMU_DCDCInit_TypeDef dcdcInit = EMU_DCDCINIT_STK_DEFAULT;
CMU_HFXOInit_TypeDef hfxoInit = CMU_HFXOINIT_DEFAULT;
uint32_t rhData = 0;
bool si7013_status;
int32_t tempData = 0;
/* Chip errata */
CHIP_Init();
/* Initalize hardware */
EMU_DCDCInit(&dcdcInit);
CMU_HFXOInit(&hfxoInit);
/* Switch HFCLK to HFXO and disable HFRCO */
CMU_ClockSelectSet(cmuClock_HF, cmuSelect_HFXO);
CMU_OscillatorEnable(cmuOsc_HFRCO, false, false);
/* Use LFXO for rtcc used by the sleeptimer */
CMU_ClockSelectSet(cmuClock_LFE, cmuSelect_LFXO);
CMU_ClockEnable(cmuClock_HFLE, true);
/* Initalize other peripherals and drivers */
gpioSetup();
sl_sleeptimer_init();
GRAPHICS_Init();
I2CSPM_Init(&i2cInit);
/* Get initial sensor status */
si7013_status = Si7013_Detect(i2cInit.port, SI7021_ADDR, 0);
GRAPHICS_ShowStatus(si7013_status);
sl_sleeptimer_delay_millisecond(2000);
/* Set up periodic measurement timer */
sl_sleeptimer_start_periodic_timer_ms(&measurement_timer, MEASUREMENT_INTERVAL_MS, measurement_callback, NULL, 0, 0);
EMU_EnterEM2(false);
while (true) {
if (measurement_flag) {
measure_humidity_and_temperature(i2cInit.port, &rhData, &tempData);
measurement_flag = false;
GRAPHICS_Draw(tempData, rhData);
}
EMU_EnterEM2(false);
}
}
/***************************************************************************//**
* @brief The actual callback for Memory LCD toggling
******************************************************************************/
static void display_callback(sl_sleeptimer_timer_handle_t *handle, void *data)
{
(void)handle;
(void)data;
mem_lcd_callback_func(mem_lcd_callback_arg);
}
/***************************************************************************//**
* @brief Register a callback function at the given frequency.
*
* @param[in] pFunction Pointer to function that should be called at the
* given frequency.
* @param[in] argument Argument to be given to the function.
* @param[in] frequency Frequency at which to call function at.
*
* @return Always return 0
******************************************************************************/
int rtccIntCallbackRegister(void (*pFunction)(void*),
void* argument,
unsigned int frequency)
{
mem_lcd_callback_func = pFunction;
mem_lcd_callback_arg = argument;
uint32_t ticks = sl_sleeptimer_get_timer_frequency() / frequency;
sl_sleeptimer_start_periodic_timer(&display_timer, ticks, display_callback, NULL, 0, 0);
return 0;
}
I am designing a temperature sensor board using an EFR32MG12 and a Si7021.
I know it is crucial to keep the temp sensor away from any sources of heat on the PCB, which is what you did on both boards mentioned here above. Yet, even with these measures, the SLTB004A still reads >7degF higher than reality (and higher than the SLTB010A). I have both boards only running the I2C, with the BLE off.
Please confirm that this is a known problem.
Did you learn any lessons on the PCB layout that could help my design. In particular, why did the PCB board gap on the SLTB004A not work?
I have an SI1147-M01-EB evaluation kit. I have downloaded the SI114x Programmers Toolkit, but I cannot get a connection to the hardware. The quick-start guide refers to Windows 7 only, so is it impossible to make this kit work on a Windows 10 machine?
In Device Manager, the device appears as an HID (Human Interface Device) rather than under Ports or USB - is this the problem?
If I launch SI1140 Control Panel, under devices I can see COM1 or TS004A572A. Pressing Connect with either device selected results in an error - unable to set baud rate for COM1 and unable to initialize SI114x. Function: InitSI114x for TS004A572A.
Also, when I launch the Firmware Updater, what should I choose from the evaluation board drop-down? Module?
SI7020 is sitting on our board, it is directly powered by 3.3V coming from X-NUCLEO-LPM01A (directly connected to GND and VDD of SI7020, no any other current flow path).
Software:
I am running STM32-CUBEMONITOR-POWER PC utility connected to X-NUCLEO-LPM01A, MCU of my board is not talking to SI7020 (no I2C communication, MCU is not powered, just SI7020 is powered).
Question:
Why SI7020 consuming that much power in standby mode?
I believe SI7020 must be in standby mode, correct? Or, Is there any command to send that in standby mode (I didn't find any such command in the datasheet)?
To whom it may concern, the datasheet does not include any information concerning the RoHS Compliancy for the Si7021-A20-GM1R so it can't be used as proof of RoHS Compliancy. We are using this part in one of our products and need a RoHS Certificate or some form of documentation stating RoHS Compliancy for our document control. I need this as soon as possible. It is holding up the release of a product. Thank you, Roger
However when I try to force measurements from the Si1133 every 1 second, even 3 seconds, the ALS stops updating its latest data after 20-30 seconds. I found out that the program hangs while waiting for REG_IRQ_STATUS register to signal that the channel measurements are completed; specifically line 838:
/* Check if the measurement finished, if not then wait */
retval += read_register(REG_IRQ_STATUS, &response);
while ( response != 0x0F ) {
wait_ms(5);
retval += read_register(REG_IRQ_STATUS, &response);
}
Is this because I am forcing a measurement too quick? When I force measurements every 10 seconds the REG_IRQ_STATUS register does change after the measurement is finished and the program takes longer to hang but it still does eventually. How fast can we poll for a measurement? Our applications requires us to make an ALS reading every 1-2 seconds. How can we go about this? Is there a work around for this? Thanks in advance for your help!
Forum
Sensors Knowledge Base Article List
There are ~30 Knowledge Base Articles (KBAs) in the Sensors section of the forum covering multiple sensors products. Sometimes, it's difficult to search for the information that you're interested in, especially when you don't know if that exists or not.
To simplify this task we have created a Sensors Knowledge Base Article List which has all the KBAs divided into sub-topics. This list only contains KBAs which are meaningful today, so you won't find anything related to legacy products. This is to avoid confusing our customers into reading material which is no longer applicable.
Additionally please check out our Sensors training page -> https://www.silabs.com/support/training/sensors
“System Error” message will be displayed on the LCD.
si1133 diode selection parameter
Can you explain the notation in the datasheet in the "operation" column of the ADCMUX row of the table for the ADCCONFIGx parameter? The notation uses for example "D + 10" for the UV "optical function." But the term "D" has no antecedent anywhere in the datasheet, as far as I know.
I assume "D" refers to a separate diode for UV.
Does the "+10" mean that the mcu on the chip adds ten to some raw result?
Also, what is the interpretation of a negative result? That the dark current is less than the light current (where you are measuring the diode in two ways, dark current and light current, and taking the difference) ?
Related to my other post about detecting daylight using UV indoors.
In the case of the PG12 STK, place a jumper to connect pins 11 and 12 together on the EXP header?
Hi,
In the case of the PG12 STK,why place a jumper to connect pins 11 and 12 together on the EXP header? Hardware decision or software decision?
I am looking forward to your reply!!
SI7020 is consuming 53.658 uA current in standby mode, that's a lot for low power design
According to the datasheet(https://www.silabs.com/documents/public/data-sheets/Si7020-A20.pdf), In standby mode SI7020 should consume 60nA but it's consuming around 53.658uA.
Hardware setup:
SI7020 is sitting on our board, it is directly powered by 3.3V coming from X-NUCLEO-LPM01A (directly connected to GND and VDD of SI7020, no any other current flow path).
Software:
I am running STM32-CUBEMONITOR-POWER PC utility connected to X-NUCLEO-LPM01A, MCU of my board is not talking to SI7020 (no I2C communication, MCU is not powered, just SI7020 is powered).
Question:
Why SI7020 consuming that much power in standby mode?
I believe SI7020 must be in standby mode, correct? Or, Is there any command to send that in standby mode (I didn't find any such command in the datasheet)?
Please, any idea/suggestion? Thanks!
-Anesh
Si1133 How to detect daylight indoors in south facing room while ignoring artificial lights, using UV.
My application is: detect day versus night, indoors, in a room with south facing windows. I am exploring the Si1133 to measure UVA. I can put the detector within 10 feet of the windows, high and facing down so the detector gets reflected UV, and never gets direct sunlight, and gets only reflected artificial lights from typical room lighting of about 400 lux white, fluorescent light. My understanding is the window glass will transmit about 50% of UVA, that the sky will scatter significant UVA, that night sky has no UVA, and that artificial lights produce negligible UVA.
Might that work? Do you have any suggestions re diffuser, physical filters, parameters of the Si1133, and which set of diodes to use? My plan is to read only the UV diode.
I want to estimate sun time by detecting sundown and sunset, despite noise from artificial lights. I don't need accuracy. I plan to take samples over many days. I understand that the weather and season will have an effect.
Si1133 - how to configure an interrupt on a sudden light change
Hi,
We are using a Si1133 chip on a board with a STM32L4 MCU. We have ported the code available at https://siliconlabs.github.io/Gecko_SDK_Doc/efm32pg12/html/si1133_8c_source.html, and we are able to measure the lux and UVI (still not tested for accuracy). We want to be able to configure the Si1133 to generate an interrupt if there is a sudden light level change (increase), is it possible this kind of application using this chip? My doubt is because if we enable the IRQ we will be interrupted on each light measurement end, we are not able to configure it to interrupt the CPU only when the threshold level is exceeded, or am I missing some alternative configuration? To be able to detect autonomously a sudden high light level it should be running in autonomous mode, so it will interrupt the MCU at the end of each measurement cycle, right?
Thanks in advance
Best regards
Fernando
Using the BMA280 accelerometer
Hi
For a research project, I am currently trying to read the acceleration data from the BMA280. At this moment I'm following a complete procedure to initialize the accelerometer. (found on the internet, I wrote the code myself). https://9apps.ooo/I use the code found on this forum to read and write the registers of the accelerometer.
The values afterwards are x=+-20mg, y=+-2mg en z=+- -19mg. I expected the values would be x=+-0g, y=+-0g en z=+- -1g when the chip is laying flat on my desk.
I convert the acceleration data in this way.
Can somebody confirm me If this is correct? Or give me the correct init from the accelerometer?
Thank you in advance
Best Regards
Si7057 temperature offset?
We are using an Si7057 in our device to measure the temperature. However we observed an offset between 0.2 and 0.4 degrees compared to older devices in the same environment. The temperature range observed is between 25 and 40 degrees and the offset seems to remain fairly constant. We observed the offset in 30 sensors so far. We are looking for an explanation, but we could not find any.
We checked the decoding of the temperature code, but we could not find an error. We use the following C code to compute the temperature:
float SI705Y_CalcTemp(uint16_t tc)
{
return 175.0 * (float)tc / 65536.0 - 45.0;
}
Unless I am mistaken, our implementation conforms almost exactly to the specification in the data sheet. Is this implementation correct?
Could this in any way be explained by measurement errors/device variability of the sensors themselves? +.3 degrees would be just within the specification, but for calibrated sensors we expected a somewhat more random distribution across devices and values roughly centered around 0.
si7021deacreasing sampling time bellow 1ms
Thanks.
Si7021 runs much hotter (+7degF) on Thunderboard Sense 2 (SLTB004A) vs Thunderboard (SLTB010A) even though isolated on PCB
Hi,
I am designing a temperature sensor board using an EFR32MG12 and a Si7021.
I know it is crucial to keep the temp sensor away from any sources of heat on the PCB, which is what you did on both boards mentioned here above. Yet, even with these measures, the SLTB004A still reads >7degF higher than reality (and higher than the SLTB010A). I have both boards only running the I2C, with the BLE off.
Please confirm that this is a known problem.
Did you learn any lessons on the PCB layout that could help my design. In particular, why did the PCB board gap on the SLTB004A not work?
Thanks.
SI1147-M01-EB with Windows 10
Hi,
I have an SI1147-M01-EB evaluation kit. I have downloaded the SI114x Programmers Toolkit, but I cannot get a connection to the hardware. The quick-start guide refers to Windows 7 only, so is it impossible to make this kit work on a Windows 10 machine?
In Device Manager, the device appears as an HID (Human Interface Device) rather than under Ports or USB - is this the problem?
If I launch SI1140 Control Panel, under devices I can see COM1 or TS004A572A. Pressing Connect with either device selected results in an error - unable to set baud rate for COM1 and unable to initialize SI114x. Function: InitSI114x for TS004A572A.
Also, when I launch the Firmware Updater, what should I choose from the evaluation board drop-down? Module?
Can someone help please?
Thanks
SI7020 is consuming 53.658 uA current in standby mode, that's a lot for low power design
According to the datasheet(https://www.silabs.com/documents/public/data-sheets/Si7020-A20.pdf), In standby mode SI7020 should consume 60nA but it's consuming around 53.658uA.
Hardware setup:
SI7020 is sitting on our board, it is directly powered by 3.3V coming from X-NUCLEO-LPM01A (directly connected to GND and VDD of SI7020, no any other current flow path).
Software:
I am running STM32-CUBEMONITOR-POWER PC utility connected to X-NUCLEO-LPM01A, MCU of my board is not talking to SI7020 (no I2C communication, MCU is not powered, just SI7020 is powered).
Question:
Why SI7020 consuming that much power in standby mode?
I believe SI7020 must be in standby mode, correct? Or, Is there any command to send that in standby mode (I didn't find any such command in the datasheet)?
Please, any idea/suggestion? Thanks!
-Anesh
Need RoHS Certificate or Some Form of RoHS Compliancy Document for Si7021-A20-GM1R
Si1133 - How fast can I force a measurement for an ALS reading?
Hi there,
I managed to get the Si1133 to work with the example code found here https://os.mbed.com/teams/SiliconLabs/code/Si1133/rev/
However when I try to force measurements from the Si1133 every 1 second, even 3 seconds, the ALS stops updating its latest data after 20-30 seconds. I found out that the program hangs while waiting for REG_IRQ_STATUS register to signal that the channel measurements are completed; specifically line 838:
/* Check if the measurement finished, if not then wait */ retval += read_register(REG_IRQ_STATUS, &response); while ( response != 0x0F ) { wait_ms(5); retval += read_register(REG_IRQ_STATUS, &response); }Is this because I am forcing a measurement too quick? When I force measurements every 10 seconds the REG_IRQ_STATUS register does change after the measurement is finished and the program takes longer to hang but it still does eventually. How fast can we poll for a measurement? Our applications requires us to make an ALS reading every 1-2 seconds. How can we go about this? Is there a work around for this? Thanks in advance for your help!