RTC (Real Time Clock) support

RE: RTC (Real Time Clock) support

Kazi Afroza Sultana — Wed, 08 Feb 2023 14:26:37 GMT

Hello,

The original case was RTC related so it would be better if you open a new case with your queries about GPIO pin state?

RE: RTC (Real Time Clock) support

Ishwar Sharma — Tue, 07 Feb 2023 08:18:07 GMT

Hi,

Thanks for sharing the information.

Need some more clarification as below.

1. What is GPIOs state during pin reset (By Pin AC31). Can we connect 3.3V on GPIO (output) during pin reset. We need this in our application. This GPIO is configured as output.

2. As per datasheet, VOH is shown minimum as VDD-0.4 V. Will it depend upon current drawn from GPIO ? If yes can you please provide graph between VOH and current drawn from GPIO.

Best regards

RE: RTC (Real Time Clock) support

Kazi Afroza Sultana — Tue, 07 Feb 2023 06:32:20 GMT

You can find hardware design file here for nRF5340DK here https://nsscprodmedia.blob.core.windows.net/prod/software-and-other-downloads/dev-kits/nrf5340-dk/nrf5340-development-kit---hardware-files-2_0_0.zip .

RE: RTC (Real Time Clock) support

Ishwar Sharma — Tue, 07 Feb 2023 01:55:11 GMT

Hi,

We are designing new board with nRF5340-QKAA device. Can you please share reference design for nRF5340-QKAA device for Schematic and PCB design where QSPI flash (external memory) is used.

Best regards

RE: RTC (Real Time Clock) support

Kazi Afroza Sultana — Fri, 20 Jan 2023 11:56:28 GMT

Hello,

You can use any ESD diode here.

RE: RTC (Real Time Clock) support

Ishwar Sharma — Wed, 18 Jan 2023 07:51:46 GMT

Hi,

Can we use ESD diodes on nRF52840 programming pins (nRF_SWDIO, nRF_SWDCLK, nRF_RESET) for ESD protection. Is there low capacitance ESD diode requirement due to high-speed signals for signal integrity.

Any suggested ESD diode part.

Best regards

RE: RTC (Real Time Clock) support

Kazi Afroza Sultana — Fri, 13 Jan 2023 13:34:33 GMT

Hello,

GPIO pin can power supply to the device if the device does not draw more current than the specific GPIO pin can provide.

Here you can find the electrical specification of GPIO https://infocenter.nordicsemi.com/topic/ps_nrf5340/gpio.html?cp=3_0_0_6_12

RE: RTC (Real Time Clock) support

Ishwar Sharma — Tue, 10 Jan 2023 08:59:50 GMT

Hi,

Can you please update regarding below points for nRF5340 device.

1. Can we use any GPIO (output) as power source for any device power supply for low power application when power supply current is required <1mA.

2. What will be max current required for any GPIO input (configured as input) when input is at high level.

3. What will be max current required for any GPIO (configured as input) when input is at low level.
4. What will be max current required for ADC input.

Best regards

RE: RTC (Real Time Clock) support

Kazi Afroza Sultana — Tue, 27 Dec 2022 11:28:38 GMT

You can find the SoC, and the Development design files in the link I sent you before. Here I have added the QIAA reference layout for SoC again.

https://nsscprodmedia.blob.core.windows.net/prod/software-and-other-downloads/reference-layouts/nrf52840/nrf52840-qiaa-reference-layout-1_3.zip

RE: RTC (Real Time Clock) support

Ishwar Sharma — Mon, 26 Dec 2022 07:15:04 GMT

Hi Kazi,

Thanks for sharing information.

Can you provide Schematic and PCB design file review for nRF52840-QIAA-R device.

Best regards

RE: RTC (Real Time Clock) support

Kazi Afroza Sultana — Tue, 20 Dec 2022 14:27:18 GMT

Hello Ishwar,

1. Can you please provide Gerber file for any Evaluation board with NRF52840-QIAA-R for reference design.

The nRF52840DK is a development board with the QIAA aQFN73 package. However, the Reference design files will be used as a good starting point. You can download this from our webpage https://nsscprodmedia.blob.core.windows.net/prod/software-and-other-downloads/dev-kits/nrf52840-dk/nrf52840-development-kit---hardware-files-3_0_0.zip. and https://nsscprodmedia.blob.core.windows.net/prod/software-and-other-downloads/reference-layouts/nrf52840/nrf52840-qiaa-reference-layout-1_3.zip

For 8 dBm Radio Tx Power we recommend using 4 components matching network as like as following figures

2. How much power losses can be saved when VDDH is used in place of VDD input and internal DC-DC converter is used with NRF52840-QIAA-R device. We will use this device for low power application (with Battery).

It is application dependent. So, it depends entirely on the input voltage on VDDH and the configured output voltage VDD.

You can use the online power profiler ((+) Online Power Profiler for Bluetooth LE - opp - Online Power Profiler - Nordic DevZone (nordicsemi.com)) to estimate the current with and without DCDC. This application does not support VDDH though.

Thanks.

Best Regards,

Kazi

RE: RTC (Real Time Clock) support

Ishwar Sharma — Fri, 16 Dec 2022 07:14:39 GMT

Hi,

1. Can you please provide Gerber file for any Evaluation board with NRF52840-QIAA-R for reference design.

Best regards

Ishwar

RE: RTC (Real Time Clock) support

Kazi Afroza Sultana — Fri, 09 Dec 2022 12:28:50 GMT

Hello,

1. There are different option given for RF signal (ANT) connection with Antenna. What should be the matching circuit. Is there any calculation for this. We need to use SR4W035 Antenna (2.4 GHz) with NRF52840-QIAA-R device.

The radio match is specific for the version of the chip which should be followed in accordance with our reference design. For the antenna, the datasheet should show the required matching network.

2. Do we need to populate series resistors and capacitors to Ground for I2C signals.

No capacitors and series resistors are needed to ground I2C lines.

3. Should we go with High drive 0 and High drive 1 if the GPIO (output) is used with connector/Cable.

Low drive mode is the default configuration when a gpio is configured as output.

S0S1 = "low drive" or standard drive

H0H1 = "high drive" for both driving output low and high. So, it depends on your application. It is not necessary to go with HOH1 always.

Thanks.

Best Regards,

Kazi Afroza Sultana

RE: RTC (Real Time Clock) support

Ishwar Sharma — Fri, 09 Dec 2022 08:22:53 GMT

Hi,

Please see my below queries:

2. Do we need to populate series resistors and capacitors to Ground for I2C signals.

3. Should we go with High drive 0 and High drive 1 if the GPIO (output) is used with connector/Cable.

Best regards

RE: RTC (Real Time Clock) support

Kazi Afroza Sultana — Tue, 06 Dec 2022 08:55:47 GMT

Hello,

You can set the unused pins as input with disconnected buffers (as GPIOs are configured as inputs with the input buffer disconnected on reset), they will not draw excessive current due to floating.

https://infocenter.nordicsemi.com/topic/ps_nrf52840/gpio.html?cp=4_0_0_5_8_1_9#register.PIN_CNF-0-31.

Thanks.

Best Regards

Kazi

RE: RTC (Real Time Clock) support

Ishwar Sharma — Tue, 06 Dec 2022 07:09:14 GMT

Hi,

Can you please update here on priority.

Best regards

RE: RTC (Real Time Clock) support

Ishwar Sharma — Mon, 05 Dec 2022 06:36:24 GMT

Hi,

Thanks.

I have one more query as below.

What is the best way to configure unused GPIOs for minimum current consumption. This is our low power mode (Battery operated) application.

Please suggest configuration for unused GPIOs.

Best regards

RE: RTC (Real Time Clock) support

Kazi Afroza Sultana — Fri, 02 Dec 2022 10:21:38 GMT

Hello,

You can add external pull up resistor if you want. However, according to design, it is not necessary. All our pin has internal 13Kohm. This actually can restore the signal to high when no device is asserting it low.

Kazi

RE: RTC (Real Time Clock) support

Ishwar Sharma — Fri, 02 Dec 2022 07:34:50 GMT

Thanks for reply.

There is one more question here.

Do we need external pull up resistors on I2C signals (Data and Clock) with nRF52840 device?

Best regards

RE: RTC (Real Time Clock) support

Kazi Afroza Sultana — Wed, 23 Nov 2022 09:32:48 GMT

Hello,

Sorry for late reply. Since we do not have any peripheral for Real Time Clock ((+) RTC real-time clock - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)) so RTC is just a low power counter which cannot keep track of time during resets/power outages.

If you are thinking of using an external device, can have a look at this driver (3231) specific API RTC — Zephyr Project Documentation (nordicsemi.com). You have to implement by yourself.

There is a previous case (devzone.nordicsemi.com/.../using-nrf_connect-zephyr-with-the-comparator-interrupt) that may give you some relevant idea. There is no zephyr driver for that. So, you need to use nrfx driver instead (https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfx/drivers/comp/driver.html).

Hope it helps. Thanks.

Best Regards,

Kazi Afroza Sultana

RE: RTC (Real Time Clock) support

Ishwar Sharma — Mon, 21 Nov 2022 07:54:37 GMT

Hi,

Can you please update here.

Best regards

RE: RTC (Real Time Clock) support

Ishwar Sharma — Thu, 17 Nov 2022 15:25:47 GMT

Hi,

The RTC (Real Time clock) is needed for time and date.

Best regards

Ishwar

RE: RTC (Real Time Clock) support

Kazi Afroza Sultana — Thu, 17 Nov 2022 14:53:18 GMT

Hello Ishwar,

It may be possible. What do you intend to do implementing Real Time Clock in your design? A little bit details information is helpful.

Thanks.

Best Regards,

Kazi Afroza Sultana