example I2C bus talking to MMA8653FC

RE: example I2C bus talking to MMA8653FC

Karl Ylvisaker — Mon, 23 Mar 2020 13:16:52 GMT

Hello,

[quote user="K Rhodes"]The code builds without errors or warning. Below is the pca10056.h that I used for my testing. The only line changed for the TWI testing was the line #define ARDUINO_SDA_PIN 29 // SDA signal pin. The 28 was changed to 29.[/quote]

That should be no problem, just remember to check the Pin Assignment section before changing which pins are used for different purposes. Especially pay attention to the pins recommended for low-frequency signals, since they are close to the radio( I am unable to check this for you since I do not know exactly which SoC variant you are working with.

[quote user="K Rhodes"]I am starting to agree with you, there is a PCB problem.[/quote]

Regardless of your SDA pin change, you should be able to see the SCL signal generated from the example.
If you have many any other modifications to the TWI_scanner example, than the pca10056.h changes mentioned earlier, it would also be beneficial if you could share your entire source code.

Do you have a Development Kit at hand, and if so; could you load your application on to the development kit, to verify that you are able to see the output as expected on your oscilloscope?
This would help us verify if the issue is with the PCB, or the code.

For future reference, please use the "Insert code" option when posting code to DevZone, to significantly increase readability.

Best regards,
Karl

RE: example I2C bus talking to MMA8653FC

K Rhodes — Fri, 20 Mar 2020 21:01:15 GMT

The code builds without errors or warning. Below is the pca10056.h that I used for my testing. The only line changed for the TWI testing was the line #define ARDUINO_SDA_PIN 29 // SDA signal pin. The 28 was changed to 29.

I am starting to agree with you, there is a PCB problem.

// LEDs definitions for PCA10056
#define LEDS_NUMBER    3

#define LED_1          NRF_GPIO_PIN_MAP(0,29)
#define LED_2          NRF_GPIO_PIN_MAP(1,15)
#define LED_3          NRF_GPIO_PIN_MAP(1,13)
//#define LED_4          NRF_GPIO_PIN_MAP(0,16)
#define LED_START      LED_1
#define LED_STOP       LED_3

#define LEDS_ACTIVE_STATE 1

#define LEDS_LIST { LED_1, LED_2, LED_3}//, LED_4 }

#define LEDS_INV_MASK LEDS_MASK

#define BSP_LED_0      10
#define BSP_LED_1       8
#define BSP_LED_2       6
//#define BSP_LED_3      16

#define BUTTONS_NUMBER 4

#define BUTTON_1       4
#define BUTTON_2       3
#define BUTTON_3       20
#define BUTTON_4       21
#define BUTTON_PULL    NRF_GPIO_PIN_PULLDOWN

#define BUTTONS_ACTIVE_STATE 1

#define BUTTONS_LIST { BUTTON_1, BUTTON_2, BUTTON_3, BUTTON_4 }

#define BSP_BUTTON_0   BUTTON_1
#define BSP_BUTTON_1   BUTTON_2
#define BSP_BUTTON_2   BUTTON_3
#define BSP_BUTTON_3   BUTTON_4

//#define RX_PIN_NUMBER 8
//#define TX_PIN_NUMBER 6
//#define CTS_PIN_NUMBER 7
//#define RTS_PIN_NUMBER 5
//#define HWFC           true
//
//#define BSP_QSPI_SCK_PIN   19
//#define BSP_QSPI_CSN_PIN   17
//#define BSP_QSPI_IO0_PIN   20
//#define BSP_QSPI_IO1_PIN   21
//#define BSP_QSPI_IO2_PIN   22
//#define BSP_QSPI_IO3_PIN   23
//
//
//// serialization APPLICATION board - temp. setup for running serialized MEMU tests
//#define SER_APP_RX_PIN              NRF_GPIO_PIN_MAP(1,13)    // UART RX pin number.
//#define SER_APP_TX_PIN              NRF_GPIO_PIN_MAP(1,14)    // UART TX pin number.
//#define SER_APP_CTS_PIN             NRF_GPIO_PIN_MAP(0,2)     // UART Clear To Send pin number.
//#define SER_APP_RTS_PIN             NRF_GPIO_PIN_MAP(1,15)    // UART Request To Send pin number.
//
//#define SER_APP_SPIM0_SCK_PIN       NRF_GPIO_PIN_MAP(0,27)     // SPI clock GPIO pin number.
//#define SER_APP_SPIM0_MOSI_PIN      NRF_GPIO_PIN_MAP(0,2)      // SPI Master Out Slave In GPIO pin number
//#define SER_APP_SPIM0_MISO_PIN      NRF_GPIO_PIN_MAP(0,26)     // SPI Master In Slave Out GPIO pin number
//#define SER_APP_SPIM0_SS_PIN        NRF_GPIO_PIN_MAP(1,13)     // SPI Slave Select GPIO pin number
//#define SER_APP_SPIM0_RDY_PIN       NRF_GPIO_PIN_MAP(1,15)     // SPI READY GPIO pin number
//#define SER_APP_SPIM0_REQ_PIN       NRF_GPIO_PIN_MAP(1,14)     // SPI REQUEST GPIO pin number
//
//// serialization CONNECTIVITY board
//#define SER_CON_RX_PIN              NRF_GPIO_PIN_MAP(1,14)    // UART RX pin number.
//#define SER_CON_TX_PIN              NRF_GPIO_PIN_MAP(1,13)    // UART TX pin number.
//#define SER_CON_CTS_PIN             NRF_GPIO_PIN_MAP(1,15)    // UART Clear To Send pin number. Not used if HWFC is set to false.
//#define SER_CON_RTS_PIN             NRF_GPIO_PIN_MAP(0,2)     // UART Request To Send pin number. Not used if HWFC is set to false.
//
//
//#define SER_CON_SPIS_SCK_PIN        NRF_GPIO_PIN_MAP(0,27)    // SPI SCK signal.
//#define SER_CON_SPIS_MOSI_PIN       NRF_GPIO_PIN_MAP(0,2)     // SPI MOSI signal.
//#define SER_CON_SPIS_MISO_PIN       NRF_GPIO_PIN_MAP(0,26)    // SPI MISO signal.
//#define SER_CON_SPIS_CSN_PIN        NRF_GPIO_PIN_MAP(1,13)    // SPI CSN signal.
//#define SER_CON_SPIS_RDY_PIN        NRF_GPIO_PIN_MAP(1,15)    // SPI READY GPIO pin number.
//#define SER_CON_SPIS_REQ_PIN        NRF_GPIO_PIN_MAP(1,14)    // SPI REQUEST GPIO pin number.
//
//#define SER_CONN_CHIP_RESET_PIN     NRF_GPIO_PIN_MAP(1,1)    // Pin used to reset connectivity chip
//
// Arduino board mappings
#define ARDUINO_SCL_PIN             27    // SCL signal pin
#define ARDUINO_SDA_PIN             29    // SDA signal pin
#define ARDUINO_AREF_PIN            12     // Aref pin

//#define ARDUINO_13_PIN              NRF_GPIO_PIN_MAP(1, 15) // Digital pin 13
//#define ARDUINO_12_PIN              NRF_GPIO_PIN_MAP(1, 14) // Digital pin 12
//#define ARDUINO_11_PIN              NRF_GPIO_PIN_MAP(1, 13) // Digital pin 11
//#define ARDUINO_10_PIN              NRF_GPIO_PIN_MAP(1, 12) // Digital pin 10
//#define ARDUINO_9_PIN               NRF_GPIO_PIN_MAP(1, 11) // Digital pin 9
//#define ARDUINO_8_PIN               NRF_GPIO_PIN_MAP(1, 10) // Digital pin 8
//
//#define ARDUINO_7_PIN               NRF_GPIO_PIN_MAP(1, 8) // Digital pin 7
//#define ARDUINO_6_PIN               NRF_GPIO_PIN_MAP(1, 7) // Digital pin 6
//#define ARDUINO_5_PIN               NRF_GPIO_PIN_MAP(1, 6) // Digital pin 5
//#define ARDUINO_4_PIN               NRF_GPIO_PIN_MAP(1, 5) // Digital pin 4
//#define ARDUINO_3_PIN               NRF_GPIO_PIN_MAP(1, 4) // Digital pin 3
//#define ARDUINO_2_PIN               NRF_GPIO_PIN_MAP(1, 3) // Digital pin 2
//#define ARDUINO_1_PIN               NRF_GPIO_PIN_MAP(1, 2) // Digital pin 1
//#define ARDUINO_0_PIN               NRF_GPIO_PIN_MAP(1, 1) // Digital pin 0
//
//#define ARDUINO_A0_PIN              3     // Analog channel 0
//#define ARDUINO_A1_PIN              4     // Analog channel 1
//#define ARDUINO_A2_PIN                20    // Analog channel 2 SENSOR 1
//#define ARDUINO_A3_PIN                21    // Analog channel 3 SENSOR 2
//#define ARDUINO_A4_PIN                13    // Analog channel 4 SENSOR 3
//#define ARDUINO_A6_PIN                14    // Analog channel 5 SENSOR 4
//

#ifdef __cplusplus
}
#endif

#endif // PCA10056_H

RE: example I2C bus talking to MMA8653FC

Karl Ylvisaker — Thu, 19 Mar 2020 17:06:54 GMT

Hi Kevin,

If you are running an unmodified version of the twi_sensor example from the SDK, but you are not seeing anything on your oscilloscope - then I suspect that there might be a hardware or pin-configuration issue.
Could you post the modifications you did to the pca10056.h file? Does the code compile properly, and flash to the nRF52810?
Do you see where in the code the application stops? If it is a hardware connection I would think it stops in the loop waiting for a successful TWI transfer.
Which pins are you using for SDA and SCL, in your modified version, and how have you made these modifications?

Best regards,
Karl

RE: example I2C bus talking to MMA8653FC

Mojo — Wed, 18 Mar 2020 20:47:19 GMT

Have a look at these sensor drivers https://github.com/IOsonata/IOsonata/tree/master/src/sensors

usage examples : https://github.com/IOsonata/IOsonata/tree/master/exemples/sensor

examples with ble to send sensor data to Thingy App. : https://github.com/IOsonata/IOsonata/tree/master/ARM/Nordic/exemples/BlueIOThingy

RE: example I2C bus talking to MMA8653FC

K Rhodes — Wed, 18 Mar 2020 16:53:27 GMT

Thanks Karl for getting back to me.

Yes, when I said that I see no SCL signal I was talking about on my oscilloscope. The code that I am running is the example code \example\perpheral\twi_scanner in the nRF5 SDK 16. I did update the pca10056.h file with the correct pin assignment for SLC and SDA.

RE: example I2C bus talking to MMA8653FC

Karl Ylvisaker — Mon, 16 Mar 2020 15:03:08 GMT

Well, yes and no. The example I sent does actually demonstrate how to use TWI ( which is I2C ).
The successful readings from the sensor is sent to the serial port using UART.

So, the UART part is just to visualize the data for you. The data is in fact retrieved from the sensor using TWI.
Please have a closer look at the documentation I linked, or at the examples source code.

Best regards,
Karl

RE: example I2C bus talking to MMA8653FC

K Rhodes — Mon, 16 Mar 2020 14:24:58 GMT

The example you sent is using a UART not I2C. Are there any I2C example?

RE: example I2C bus talking to MMA8653FC

Karl Ylvisaker — Mon, 16 Mar 2020 07:42:09 GMT

Hi,

[quote user=""]I never see the clock signal generated.[/quote]

Does this mean that you are using an oscilloscope on the SCL pin, and seeing nothing?
If so, could you please share your code? That way I would more easily be able to pinpoint what is not working.

[quote user=""]Can someone point me to some example code using the nRF52 talking to any Accelerometer.[/quote]

Have you seen the TWI sensor example? In this example, it is demonstrated how to setup and communicate between a Nordic SoC and an arbitrary sensor, using TWI.
If you are unable to see anything on your SCL pin, you need to make sure that the initialization and usage is correct.
Do you have a debugger available, so you may step through your code to see what is going on?

Best regards,
Karl