I2C example with NRF51822

RE: I2C example with NRF51822

ALi — Wed, 10 Aug 2016 07:38:26 GMT

copy these files (.c,.h) to near Project main.c file and after that import to your project in Keil.

RE: I2C example with NRF51822

Chris Lovett — Tue, 03 May 2016 18:10:29 GMT

Ok, you are right, it looks like my code is using an older version of the Nordic sdk. The new examples that are bundled with Keil C use nrf_drv_twi_init and nrf_drv_twi_tx.

RE: I2C example with NRF51822

Chris Lovett — Mon, 25 Apr 2016 22:54:26 GMT

My code is assuming the SoftDevice is available, so you must have called twi_master_init already, then my helper functions can work from there using twi_master_transfer. A read is also a "transfer" because you have to write the register address that you want to read from.

RE: I2C example with NRF51822

Brook Gebremedhin — Mon, 25 Apr 2016 22:14:25 GMT

@clovett ,

i was seeing your wrapper you used twi_master_transfer both for reading and writing i2c data.

dont we need to use nrf_drv_twi_tx and nrf_drv_twi_rx as well ?

And what will be the twi initialization in this case ? tnx

RE: I2C example with NRF51822

muhkuhns — Sun, 19 Apr 2015 17:15:58 GMT

This won't work with Softdevices enabled - will it?

RE: I2C example with NRF51822

Mario — Wed, 04 Feb 2015 17:58:42 GMT

Hi Steve, I saw that link. It appears under "drivers". I do have the "twi_master.h", "twi_hw_master.c" and "twi_sw_master.c" within drivers folder, but in examples folder I can't find anything related with TWI or I2C. I don't know what is wrong but I'm getting a headache with this.

If I create a project and write #include "twi_master.h" it says it can't find that file. It doesn't happen with "simple_uart.h" for example and I don't understand why because both of them are within the same folder "drivers" (where the uvision is supossed to find header files)

The path of my examples folder is this

C:\Keil_v5\ARM\Pack\NordicSemiconductor\nRF_Examples\7.2.0\peripheral

RE: I2C example with NRF51822

Steven Wik — Wed, 04 Feb 2015 16:43:03 GMT

Hi Mario,

Have you tried this link here?

I'm not sure why you can't find the example in your SDK's file path - it looks like the latest SDK still has the example under the nrf6310 folder. Are you looking in the correct folder?

-Steve

RE: I2C example with NRF51822

Mario — Wed, 04 Feb 2015 16:34:23 GMT

Hello,

I am trying to find the I2C example and I can't. It doesn't appear here:

developer.nordicsemi.com/.../a00038.html

And it doesn't either in my PC folder. It is possible that it was available in SDK v5.1.0 version but it's not anymore?

Thank you.

RE: I2C example with NRF51822

Chris Lovett — Thu, 24 Apr 2014 20:43:02 GMT

Yeah, it looks like twi_sw_master.c is designed to work with only one channel. Notice how it hard codes your twi_master_config.h definitions of TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER and TWI_MASTER_CONFIG_DATA_PIN_NUMBER. So if you do something like this:

#define TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER (23U) #define TWI_MASTER_CONFIG_DATA_PIN_NUMBER (22U)

Then it can only talk one channel. Interestingly the twi_sw_master.c doesn't seem to use NRF_TWI0 or NRF_TWI1 directly. So I'm guessing you'd could make your TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER and TWI_MASTER_CONFIG_DATA_PIN_NUMBER definitions static integers so you can switch them, assuming you only want to chat on one channel at a time. But then you have to remember to keep switching them back and forth which could get messy in your app logic.

It might be better rewrite the twi_sw_master.c library code so that it takes channel id arguments. For example the macro for TWI_SCL_HIGH() would have to be TWI_SCL_HIGH(TWI0) or TWI_SCL_HIGH(TWI1) which means re-writing this macro :

#define TWI_SCL_HIGH() do { NRF_GPIO->OUTSET = (1UL << TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER); } while(0) /*!< Pulls SCL line high */

so it takes argument, like this:

#define TWI_SCL_HIGH(pin) do { NRF_GPIO->OUTSET = (1UL << pin); } while(0) /*!< Pulls SCL line high */

I'm not sure why they didn't do all this in the first place... I notice they did support both channels in the spi_master code... so perhaps you can copy that approach essentially each spi* function take a spi_base_address argument. I'd expect all the twi_master* functions to similarly take a TWI channel index. twi_master_init could then take a flag saying which channels you support and it could store a static mapping to your pin definitions which you define like this:

#define TWI0_MASTER_CONFIG_CLOCK_PIN_NUMBER (23U) #define TWI0_MASTER_CONFIG_DATA_PIN_NUMBER (22U)

#define TWI1_MASTER_CONFIG_CLOCK_PIN_NUMBER (24U) #define TWI1_MASTER_CONFIG_DATA_PIN_NUMBER (25U)

RE: I2C example with NRF51822

Kris — Thu, 24 Apr 2014 00:17:09 GMT

Hello ,

Are there any example that implement I2C on both the channels (TWI0 & TWI1) ?

//K

RE: I2C example with NRF51822

ABDELLI-W — Wed, 19 Mar 2014 11:57:57 GMT

Thank you so much Chris.

RE: I2C example with NRF51822

Chris Lovett — Wed, 19 Mar 2014 04:47:12 GMT

I wrote my own little wrapper that might help, see attached i2c.c.

i2c.c

RE: I2C example with NRF51822

ABDELLI-W — Mon, 10 Mar 2014 16:19:12 GMT

Hi, Thank you for you Answering. I've seen the example of Nordic, but for me it does not explain very well for me how it implemnts the read/write frame.

RE: I2C example with NRF51822

Steven Wik — Mon, 10 Mar 2014 15:33:49 GMT

Hi,

There is an example project using I2C on the nRF51822 - they refer to it as a "Two Wire Interface" (TWI) in the PS and RM, please see Section 27 of the RM 2.1 for a complete description.

The example program of an I2C master can be found in the stack example path below:

\Nordic Semiconductor\nRF51 SDK_v5.1.0.36092\Nordic\nrf51822\Board\nrf6310\twi_sw_master_example

Cheers, Steve

RE: I2C example with NRF51822

ABDELLI-W — Mon, 10 Mar 2014 15:29:12 GMT

I want to create an I2C Library an dto use it in my sensors. so I am trying to create write funtion and read function to I2C BUS.