SD-Card writing blocks ADC

RE: SD-Card writing blocks ADC

Ole Bauck — Fri, 13 Jan 2017 12:44:48 GMT

If your code is restarting it may be because the code entered an error condition. Try to define DEBUG globally, go into debug mode and check where you get an error, see here.

RE: SD-Card writing blocks ADC

Lea — Fri, 13 Jan 2017 11:05:59 GMT

I can only tell what settings I made. My init Frequency is 250kHz and my APP_SDCARD_FREQ_DATA is set to 8 MHz. But i think if this would be the problem no data should be written on your card. Have you tried using a different sd card or setting down your samplingrate?

RE: SD-Card writing blocks ADC

Ankush — Fri, 13 Jan 2017 10:56:32 GMT

Hi,

Some data is being written on SD card card but after some time code gets restarted. Is it the issue of clock frequency of SPI or sampling frequency of SAADC. SPI0_DEFAULT_FREQUENCY and APP_SDCARD_FREQ_INIT are set to 4 MHz. and Sampling frequency of SAADC is 1000sps. I am sampling SAADC using PPI.

RE: SD-Card writing blocks ADC

Ankush — Fri, 13 Jan 2017 10:52:52 GMT

Yes, exactly I have used SPI_DEFAULT_CONFIG_IRQ_PRIORITY as 3 to set priority level for SPI(SD card).

RE: SD-Card writing blocks ADC

Lea — Fri, 13 Jan 2017 10:49:49 GMT

So did you set the interrupt priority of the spi by setting the SPI_DEFAULT_CONFIG_IRQ_PRIORITY in the sdk_config.h? Because the app_sdcard.c file uses this define for setting the priority.

RE: SD-Card writing blocks ADC

Ankush — Fri, 13 Jan 2017 10:38:44 GMT

Hi Lea,

My code is getting restarted when I am doing the sampling of SAADC at 1000 sps and writing to SD card. I am just setting the flag as soon as get SAADC interrupt. Now In sdk_config.h I have set the priority for SAADC as 7 and for SPI0 it is 3..But same thing is happening

RE: SD-Card writing blocks ADC

Lea — Fri, 13 Jan 2017 09:29:10 GMT

Hi Ankush, is the Sending the problem or writing on SD Card while sampling the ADC? I had the same problem, my code got stuck when I tried to write my samples on SD Card. So I now set the interrupt priority of my adc to 6 and the one of my sd card to 3. Before they had the same priority or adc had a higher priority. So have you tried writing your samples on SD card without sending them and did this work?

RE: SD-Card writing blocks ADC

Ankush — Fri, 13 Jan 2017 07:41:34 GMT

Hi Ole,

I am getting similar kind of issue. I want to write to SD card the SAADC samples and at the same time streaming over BLE at 1ksps rate. I am calling both sending over BLE and writing to SD card function in main context. In ISR I am just updating the flags and checking the same in main loop.

Now the issue is as soon as I enable the BLE streaming code is getting stopped. I have this question in this thread with my complete code, but still I am getting the same issue.

Can you suggest anything about this?

RE: SD-Card writing blocks ADC

Lea — Wed, 11 Jan 2017 15:17:30 GMT

Thanks a lot.

I called the f_write() function in the ADC interrupt context so it blocked the next interrupt. I now call it from the main where I observe a Flag. From the ADC interrupt I now only call a function that saves my ADC Values in a buffer.

RE: SD-Card writing blocks ADC

Ole Bauck — Mon, 09 Jan 2017 11:55:16 GMT

Where do you call the write function (f_write(..))? You should consider calling this in main context if you are calling it in interrupt context (inside an event handler/callback).

Also, the interrupt priority is higher if the value is lower (0 is the highest priority, 7 is the lowest). You should use the APP_IRQ_PRIORITY_ to set the priority, see app_util_platform.h.

RE: SD-Card writing blocks ADC

Lea — Thu, 22 Dec 2016 11:23:09 GMT

Thank you. Setting the interrupt of the saadc to a higher level is a problem, because in the beginning my saadc interrupt had been higher or the same like my spi interrupt. In this case writing on the sd card didn't worked at all. The code got stuck in the config.wait_func() function I mentioned above which waited for the write done event, that never occured. So I set the interrupt priority of the saadc to 6 and of the spi to 3.

I have now set a PPI channel between START Task and END Event of Saadc, but the problem remains. There is no sampling during the write process.

RE: SD-Card writing blocks ADC

Ole Bauck — Wed, 21 Dec 2016 12:26:25 GMT

The problem is probably that the start task is manually triggered in the buffer_convert function, which I guess you are calling inside the saadc callback. To get continuous saadc measurements without any interruptions you should have a PPI channel between the end event and the start task of the saadc, like shown in the figure here.

This should most likely work out of the box with the saadc driver, just set up the PPI channel. I have not tested this with the driver, but I know that it works from the peripheral point of view.

Alternatively have a higher interrupt level on the saadc interrupt/callback. Configure this in nrf_drv_saadc_config_t->interrupt_priority.

RE: SD-Card writing blocks ADC

Lea — Tue, 20 Dec 2016 08:59:27 GMT

Thank you, but I already trigger my SAADC sampling over a timer with PPI. I'm using TIMER1.

RE: SD-Card writing blocks ADC

Wojtek — Mon, 19 Dec 2016 17:40:13 GMT

Timer triggering SAADC sampling by PPI could be good solution.