Create a 1 microsecond timer in nRF52832

RE: Create a 1 microsecond timer in nRF52832

Sigurd — Mon, 24 Jun 2024 14:00:50 GMT

There is a delay(interrupt latency) when both entering and exiting the ARM® Cortex® -M4 ISR, + the SoftDevice also adds delay ~4us when enabled, ~2 when disabled, so overall, you won't be able to change the GPIO fast enough when doing it from interrupts.

https://infocenter.nordicsemi.com/topic/sds_s132/SDS/s1xx/processor_avail_interrupt_latency/interrupt_latency_soc_framework.html

RE: Create a 1 microsecond timer in nRF52832

chianglin — Sat, 22 Jun 2024 02:31:06 GMT

Hi,

Wiould you please tell me about the minimum interrupt time of nRF52832 timer?

RE: Create a 1 microsecond timer in nRF52832

chianglin — Fri, 21 Jun 2024 00:39:17 GMT

Hi,

I already test the method of timer, and it's maximum execute speed is 10us.

Its too slow for me.

Would you please tell me how to speed-up timer execute time?

RE: Create a 1 microsecond timer in nRF52832

Sigurd — Thu, 20 Jun 2024 15:00:19 GMT

Hi!

You can take a look at this sample for that: https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/nrf_dev_timer_example.html

PS: I'm not sure how well a bit-banged i2c at 1000 kbps on nrf52832 will work, if you are using BLE at the same time, it will likely affect the timing of the i2c.

RE: Create a 1 microsecond timer in nRF52832

chianglin — Thu, 20 Jun 2024 13:46:26 GMT

Hi,

Thank you for your example code.

It looks this example code can only toggle GPIO-pin?

When using continus timer, it will trigger a IRQ-handler while time-out, and I can do somethings (ex. Implement the I2C protocol)

Does "TIMER+GPIOTE+PPI" can trigger an IRQ handler?

Thank you,

RE: Create a 1 microsecond timer in nRF52832

Sigurd — Wed, 19 Jun 2024 14:46:09 GMT

Hi!

[quote user="chianglin"]I want to simulate a 1MHz I2C server[/quote]

For a 1MHz signal, I suggest using TIMER+GPIOTE+PPI.

See the code in this post:

RE: nRF52 clock in and out

adjust the " NRF_TIMER1->CC[0] = 1; // Adjust the output frequency by adjusting the CC." , to get the desired frequency

[quote user="chianglin"]nrf52832's I2C master can only support 400KHz.[/quote]

For nRF5340 we have

Supported baud rates: 100, 250, 400 and 1000 kbps -> https://infocenter.nordicsemi.com/topic/ps_nrf5340/twim.html?cp=4_0_0_6_35

RE: Create a 1 microsecond timer in nRF52832

chianglin — Wed, 19 Jun 2024 12:49:51 GMT

HI,

Actually, I want to simulate a 1MHz I2C server, but nrf52832's I2C master can only support 400KHz.

Thank you

RE: Create a 1 microsecond timer in nRF52832

Sigurd — Wed, 19 Jun 2024 11:54:04 GMT

[quote user=""]If I want to create a 1 microsecond continuous timer, and it can change some GPIO pin status when timer-IRQ ioccur.[/quote]

Do you want to create some PWM signal or something? Then I suggest using the PWM peripheral instead.