Getting Started with Seeed Studio XIAO nRF52840 Series | Seeed Studio Wiki

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Getting Started with Seeed Studio XIAO nRF52840 Series | Seeed Studio Wiki

Getting Started with Seeed Studio XIAO nRF52840 Series

https://wiki.seeedstudio.com/XIAO_BLE/

[nhatminh2h]

Hi, I am trying to get some IMU reading using the XIAO NRF52840 Sense Plus and the IMU was failing at the begin() everytime (device error), I have tried with all versions of board and LSM6DS3 libraries. The only way it would work is if I change the board type to XIAO NRF52840 Sense (not Plus). I have manufactured a breakout board which specifically uses the Sense Plus, would this workaround affect further development?

[nfs0619]

Thank you for your feedback. We have received your message and are currently arranging for debugging. If you do not receive further updates, please feel free to reach out to our technical support at techsupport@seeed.io for further assistance. Thank you for your support and understanding.

[nfs0619]

Hi, this issue can be solved by reinstalling the XIAO nRF52840 board package.

[webdevsumit]

Hi, It is an amazing module and it solves all the issues that we were facing while designing custom PCB so we chose to use this but the current Bootloader doesn't support the BT DFU. Is there any solution for that? It is super necessary for us as we build wearable devices.

[nfs0619]

Thanks for your feedback — we’re really glad to hear the module has been helpful in your project! Regarding BT DFU support with the current bootloader, we don’t have an official solution or documentation for that at the moment. However, this post might be helpful to you: OTA DFU update with XIAO nRF52840 BLE - Seeed Forum
You may also want to browse our forum to see if other users have shared related solutions that fit your needs.
If you have any other questions, I recommend reaching out to our technical support team at techsupport@seeed.io.

[maker-lukas]

im working on a project that needs the xiao nrf plus and i'm making a pcb for it and there is not symbol for it only footprint

[maker-lukas]

Yes exactly

[maker-lukas]

I can’t find it at least

[nfs0619]

Hi, we are currently preparing the KiCad symbol file for the XIAO nRF52840 Plus. Thanks for your patience!

[maker-lukas]

cool thats really helpfull

[nfs0619]

Hi, this file should be what you're looking for. We'll also include it in the official documentation soon. Thank you for your support and patience!

Seeed_Studio_XIAO_Series_kicad_sym.zip

[yousseffamgadd]

how to control the sensitivity of IMU accelerometer (double tab)?

[ReKST-117]

Hi,

You could refer to the sensor driver. Specifically, it would the LSM6DS3.h file. The link is given below:
https://github.com/Seeed-Studio/Seeed_Arduino_LSM6DS3/blob/master/LSM6DS3.h

You should find the definition of linear & angular sensor full-range scale value from these definitions:
typedef enum {
LSM6DS3_ACC_GYRO_FS_XL_2g = 0x00,
LSM6DS3_ACC_GYRO_FS_XL_16g = 0x04,
LSM6DS3_ACC_GYRO_FS_XL_4g = 0x08,
LSM6DS3_ACC_GYRO_FS_XL_8g = 0x0C,
} LSM6DS3_ACC_GYRO_FS_XL_t;

typedef enum {
LSM6DS3_ACC_GYRO_FS_G_245dps = 0x00,
LSM6DS3_ACC_GYRO_FS_G_500dps = 0x04,
LSM6DS3_ACC_GYRO_FS_G_1000dps = 0x08,
LSM6DS3_ACC_GYRO_FS_G_2000dps = 0x0C,
} LSM6DS3_ACC_GYRO_FS_G_t;

If you check the sensor datasheet, page 61 & 62, section 9.13 and 9.14, you would found two registers which controls the output data rate as well as full-scale range. In that case, you should write the values defined above to the FS_XL1, FS_XL0 bits (for linear sensor range) and FS_G1, FS_G0 (for angular sensor range) in order to set the full-scale range and the sensitivity = full-scale range/number of bits(LSB). Again, you could find the full-scale range to sensitivity value mapping on page 21 of the datasheet.

Sensor datasheet link: https://www.st.com/resource/en/datasheet/lsm6ds3tr-c.pdf

Regards

[notmyne]

Hello, I am currently working with the nRF52840 (Sense) Plus, and it is quite unclear within this wiki if the pins P0.04 & P0.05 on the Plus version are I2C capable, and whether or not all the added pins (compared to the base version) can be used as digital or analog pins (e.g. P0.15). Thank you in advance!

[HM-sur]

We will fix it quickly and thank you for the bug

[notmyne]

Hi, thank you for taking notice of my comment.

Meanwhile, could you please tell me if I2C is available on the Plus version of this board and if so are they also on the same pin number than the base version? And if the additional pins could be used as Digital I/Os? Thank you!

[HM-sur]

Hi, the Plus also have I2C function, and they have same pin number.
The additional pins can used the Digital pins, but there are no software-defined Analog pins.

[notmyne]

Perfect! Thank you very much!

[pavel-perina]

I have some observations about the firmware I kind of bricked and recovered my board it using Raspberry Pi Pico debug probe. However, I noticed few inconsistencies:

• original firmware for the XIAO nRF52840 was firmware for sense version (by USB VID:PID and partition name XIAO-SENSE), despite mine not having an accelerometer.
• firmware for non-sense version does not work with Zephyr's west flash -r uf2 command, because this ID is hardcoded in zephyr/boards/seeed/xiao_ble/board.cmake. File copy works. west output:

WARNING: runners.uf2: Discovered UF2 partitions don't match Board-ID 'Seeed_XIAO_nRF52840_Sense'
FATAL ERROR: No matching UF2 partitions found

• I don't think that referenced firmware, which is four years old, is the same as firmware which came with my board. I'm quite sure there was fade-in, fade-out effect on green LED when device was in boot loader mode (configured as flash, awaiting UF2 file)

Otherwise, so far board is great. Maybe not for MicroPython, but I'm learning Zephyr with it.

[petermaerki]

I read on this Website: "Features: Battery charging chip: Supports lithium battery charge and discharge management”
When I look into the schematic I can't see the "discharge management". No protection against deep discharge.
I’d be grateful for an explanation, or for the website to be corrected if there’s a mistake.

[bleaaach]

Regarding the “battery charging chip supports lithium - ion battery charge - discharge management” you mentioned, in the actual circuit, there is a protection design on the charging side (for example, when a battery and a USB are plugged in simultaneously, it can prevent the device from being damaged). However, the discharge management does not include the deep discharge protection function and only maintains the basic discharge path.

If you need deep discharge protection, it is recommended to connect an independent protection circuit externally, or actively monitor the battery voltage during use to avoid over - discharge.

[petermaerki]

The PMOS and diode implement overload protection during USB charging. Calling this “discharge management” is simply incorrect. It has nothing to do with discharging.

[bleaaach]

Thank you for your feedback. We’ll update this description as soon as possible to better align with the actual functionality—specifically, that discharge protection relies on the battery’s own circuitry.

[mcalucin]

How strong is the WIFI? Is there a way to add an external antenna -- the 2.4GHz Rod Antenna (2.81dBi) for Seeed Studio XIAO? If so, is there any documentation on how to do this?

Thanks.

[starsprung]

There's no WiFi on this board, it's just Bluetooth

[NicHub]

Hi,

In your schematic, P0.17_CHG drives the RED_CHG LED but is also tied to the PRETERM pin of the BQ25100.
According to the datasheet, PRETERM should only be connected to a resistor to GND to set pre-charge and termination currents.

Could you clarify why P0.17_CHG is connected in both places?

Thanks!

[nfs0619]

Hi ,

Thanks for your feedback. In the initial design, R16 and R17 had a 1:1 ratio. Later we changed the ratio to 2:1, i.e. R16 = 1 MΩ and R17 = 510 kΩ. With this configuration, the maximum voltage at P0.31 is 3.6 V, which is within the allowed range (see images below).

[mself]

Is the charger actually a BQ25101 and pin C1 is ~CHG rather than PRETERM? That would make more sense. This pin drives the red LED and the charge status can be read on P0.17

[grilliiiiii]

Is the charger actually a BQ25101 and pin C1 is ~CHG rather than PRETERM? That would make more sense. This pin drives the red LED and the charge status can be read on P0.17

After my investigation, I found that the chip model on the schematic is indeed incorrect and should be changed to BQ25101.
We have already arranged for the modification and will upload the correct version to the wiki as soon as possible.

[PlvLuin-243]

• I'm having a problem now that only when I manually press to enter DFU can I select the port and load the code using arduino.
• and after loading is complete the device resets so it exits DFU mode, ideally there will be a COM port to see on the serial monitor but when the device runs normally there is no COM port.
• if I erase all flash then the com port appears.

[nfs0619]

Hi, I recommend contacting our technical support team at techsupport@seeed.io and providing details such as the product you’re using and the steps you’ve taken. This will help them locate and resolve the issue more efficiently.

[nickeyjoy]

You can first try to reset the board by clicking the "Reset Button" once. If that does not work, rapidly click it twice to enter bootloader mode. If that also doesn't work, disconnect the board from the PC, and connect the board again.

[chbeeler]

What type of 3.3V regulator is on the XIAO nRF52840 Sense? The schematic doesn't say. I want to know how much current I can pull from the 3.3V pin.

[nfs0619]

We use the model "SMD IC PMICLDO-3.3V-250mA-Low IQ-TQFN-1×1-4AL", which supports a fixed output of 3.3V and a rated output current of 250mA. To avoid regulator overload or performance abnormalities caused by insufficient heat dissipation, it is recommended that the maximum current of external devices connected to the 3.3V pin does not exceed 150-200mA.

[semperion0201-arch]

i am confused with the pin layouts
according to the top list:
D16 BAT P0.31 GPIO
ADC_BAT P0.14 Read the BAT voltage value

but in the schematics P0.31 is the input to read the battery level and in FAQ Q3 P0.14 should be (ADC_BAT) analoginput or digital low

[semperion0201-arch]

And shouldn't the reading a 2:1 instead of a nearly 1:1?
ADC_BAT = 3764 D16 = 3783

[semperion0201-arch]

How to check if i have a version with 1:1 ratio like you mentioned
"Thanks for your feedback. In the initial design, R16 and R17 had a 1:1 ratio. Later we changed the ratio to 2:1, i.e. R16 = 1 MΩ and R17 = 510 kΩ. With this configuration, the maximum voltage at P0.31 is 3.6 V, which is within the allowed range (see images below)."

[semperion0201-arch]

maybe a code example would be nice. i have the plus (without sense) board
because it looks like i have a 1:1 ratio board and need to correct the readings to meet real measurments
"return raw * (3.6 / 4095.0) * 1.088;"