Hi all iam trying to read the differential analog voltage between AIN0 and AIN1 which is pin0.02 and pin0.03 and print the voltage which will be in micro volts from 400 micorvolt, and since the examples in sdk uses log_flush i could not get the data or not acess any data from that, i need to acess the data and print the data using uart, can anybody help me out in this, thankyou.
Hello Nagaraj JP,
Not sure if I can assist you, but a few details about your starting point in terms of software libraries and targeted hardware will be useful for the community here to know. Are you working with Nordic Semi's nRF Connect SDK, such as found at https://github.com/nrfconnect/sdk-nrf/tags? This was my starting point a few months back. I am using Nordic's sdk-nrf release version 1.6.1.
If yes to this question you are most likely then working with a Zephyr RTOS based app. I've seen some posts here, however, in which developers are working with a non-Zephyr code base or project.
If your application is Nordic SDK plus Zephyr based, then you may be able to get your targeted board's UART functioning quickly via the "hello world" sample app in downloaded SDK. For myself there were several steps to download and configure the various tools and SDK software pieces, but in the end I have a `west` workspace (where `west` is, you may already know, a Python based project manager at the command line). In that `west` workspace the `west` utility has eased the git cloning of Nordic's SDK, an associated fork of the Zephyr project, and some nice sample apps both from Nordic and from Zephyr.
In about a day's time I was able to enable any of three on-chip UARTs in my development board's microcontroller. The "hello world" sample in [west_workspace]/zephyr/samples/hello_world contains almost no code, and its prj.conf file is effectively empty. But as the sample app builds part of the build toolchain goes out and reads a DTS (device tree source) board file for my particular targeted board. Capturing and reviewing the build messages, I could then study that board.dts file, and see how the UART is assigned to pins, given a default BAUD rate, and enabled in the context of Zephyr RTOS. Those things allowed me to correctly configure my terminal emulator, and later to move between UART instances and change BAUD rate settings as needed.
The minimal source file from "hello_world" provided me an include statement which I have used many times since in development versions of code:
`#include <sys/printk.h>`
In Zephyr based apps (Zephyr 2.6.0 in my case) this include permits me to call `printk()` family functions. Printk() seems to behave just like `printf()`.
If I have shared things you already know my apologies. If you are just getting started in a Zephyr based project, you will likely want to study some about Device Tree Source, and the .dts and .overlay files you will and can use in Zephyr RTOS based projects.
Once you can build and see correct "hello world" output, you can start to add your own custom routines and code to that project. To pull the sample app out of Nordic's larger SDK will require some additional project configuration steps. Those lay outside the scope of your question, and are better answered by a couple of good tutorials and likely some further interaction with the forum community.
Hope this helps.
- Ted
Thankyou Ted for the effort you have put for me.
details about your starting point in terms of software libraries and targeted hardware will be useful for the community here to know
My sdk is version 17.1.0 and my target board is nrf 52840 dk board. I can now print the data in uart , only thing is that i could not access the data that the adc has converted, i first tried the single ended adc in the example and tried to integrate it with my code but there was error in compiling. Since the example code uses log_flush for printing the data i could not find where the data is, but some raw data is been printed which is varied when the adc is varied.So my first aim is to acess the data from the single ended code and to print the data, and then to implement the differential adc and then to print that data.
And im not using any RTOS in the code, it is just simply a basic implementation.
Hello Nagaraj,
Glad to hear you have made some progress in obtaining ADC readings, if so far just the raw readings. Your original mention of function log_flush() had me curious. I've searched all of sdk-nrf v1.6.1 and found only a single reference to log_flush():
./modules/lib/mcumgr/cmd/log_mgmt/port/mynewt/src/mynewt_log_mgmt.c:267: rc = log_flush(log);
I cannot tell where this function is defined. It's definition does not appear to be a part of Nordic nRF SDK v1.6.1 which I am using. Though there is a chance that it is somehow created at build time for a given project. I noticed that Zephyr apps have potentially one or more functions that part of Zephyr's sensor API, and described in the documentation for that RTOS, but their definitions don't actually exist (nor prototypes in and header files) until a Zephyr app developer creates them. Though my understanding is incomplete, there seems to be some kind of meta-compilation step for those sensor and sensor driver API functions. Perhaps log_flush() is generated similarly, and so its C code would not necessarily be visible before a sample app or project has been built.
Your project sounds interesting, Nagaraj. I hope you continue to make good progress. Keep safe,
- Ted
Hi,
I think there might be a mix up of two different SDK's here.
There is the nRF5 SDK, https://infocenter.nordicsemi.com/topic/struct_sdk/struct/sdk_nrf5_latest.html?cp=8_1
And the nRF Connect SDK (NCS) , https://infocenter.nordicsemi.com/topic/struct_sdk/struct/sdk_ncs_latest.html?cp=8_0
And the log_flush is probably refrancing https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/group__nrf__log__ctrl.html?cp=8_1_6_10_30_5_1#ga2d86a60e776a72f918d2f6cf7abc3135
Regards,
Jonathan
Check out the adc Done event, you will be able to acess the data from the DONE event in the evnet handler saadc_evt_handler. Check out how it is done in the SAADC example. The log_flush does not "flush" the data away or discard the data.
Regards,
Jonathan
