How to use the same i2c peripheral in two different pins?

[Brunelli]

Hi, I have a project using the chip nRF52832 and sdk nRF5 14.2, I'm updating the firmware to use the nRF Connect SDK 2.2(NCS).

In my project, i use spi0 and spi2, so a can just use i2c1 to talk with the i2c sensors, but 2 sensors have the same address, so I need to communicate with than using different pin.

In sdk 14.2 for every communication, I switch the instance:

nrf_drv_twi_disable(&m_twi);
nrf_drv_twi_uninit(&m_twi);

err_code = nrf_drv_twi_init(&m_twi, &twi_config, fnTWI_Event_Handler, NULL);
APP_ERROR_CHECK(err_code);
nrf_drv_twi_enable(&m_twi);

How can I do this in NCS or other kind of workaround?

[Priyanka]

Hi Rodrigo,

Could you take a look at this ticket and see if it helps?

Best Regards,

Priyanka

[Brunelli]

Hi Priyanka,
This ticket shows an example of using i2c in two different addresses, but I need to communicate with sensors that have different pinouts.
In my project I have a total of 5 sensors, where two of them have the same address so I have to programmatically change between the i2c communication pins:
4 sensors are on pins-> SDA pin 7 SCL pin 5;
1 sensor is on pins ->    SDA pin 8 SCL pin 6;
I need to alternate the i2c communication pins to be able to read all the sensors.

[Priyanka]

Hi Rodrigo,

I believe you can get a solution by using Dynamic pincontrol. You can have same addresses for sensors, but you need to use two different pins for the connections.

Please do take a look at this and do let me know how it goes.

-Priyanka

[Brunelli]

Hi, I tried to use the Dynamic pincontrol example, but I had some doubts.

1 - In the example, it says that you have to make the change before booting the system, in my case I want to change it while the device is working, is this possible?

2 - How do I return the pins to default again? Would you use the pinctrl_update_states command again? If so, what would this macro look like? PINCTRL_DT_STATE_PINS_DEFINE(DT_PATH(zephyr_user), i2c1); ?

3 - I tried following that example to change the control pins and make an i2c communication using the following code:

dts file:

&pinctrl{
	i2c1_battery_default:i2c1_battery_default {
		group1 {
			psels = <NRF_PSEL(TWIM_SDA,0,8)>,
					<NRF_PSEL(TWIM_SCL,0,6)>;
		};
	};
	i2c1_battery_sleep:i2c1_battery_sleep {
		group1 {
			psels = <NRF_PSEL(TWIM_SDA,0,8)>,
					<NRF_PSEL(TWIM_SCL,0,6)>;
			low-power-enable;
		};
	};
};

/{
	zephyr,user{
		i2c1_battery_default = <&i2c1_battery_default>;
		i2c1_battery_sleep = <&i2c1_battery_sleep>;
	};
};

conf file:

CONFIG_DYNAMIC_INTERRUPTS=y

CONFIG_PINCTRL=y
CONFIG_PINCTRL_DYNAMIC=y
CONFIG_CONSOLE_INIT_PRIORITY=70
CONFIG_I2C_INIT_PRIORITY=60
CONFIG_PM_DEVICE=y

code to initialize i2c and communicate:

BUILD_ASSERT((CONFIG_GPIO_INIT_PRIORITY < CONFIG_REMAP_INIT_PRIORITY) &&
	           (CONFIG_REMAP_INIT_PRIORITY < CONFIG_I2C_INIT_PRIORITY),
       	     "Device driver priorities are not set correctly");

PINCTRL_DT_DEV_CONFIG_DECLARE(DT_NODELABEL(i2c1));
PINCTRL_DT_STATE_PINS_DEFINE(DT_PATH(zephyr_user), i2c1_battery_default);
PINCTRL_DT_STATE_PINS_DEFINE(DT_PATH(zephyr_user), i2c1_battery_sleep);

static const struct pinctrl_state i2c1_alt[] = {
	PINCTRL_DT_STATE_INIT(i2c1_battery_default, PINCTRL_STATE_DEFAULT),
	PINCTRL_DT_STATE_INIT(i2c1_battery_sleep, PINCTRL_STATE_SLEEP),
};

static const struct i2c_dt_spec eeprom_i2c   = I2C_DT_SPEC_GET(DT_NODELABEL(eeprom_i2c));

(void) main (void){
    struct pinctrl_dev_config *i2c1_config =
    		PINCTRL_DT_DEV_CONFIG_GET(DT_NODELABEL(i2c1));
    
    pinctrl_update_states(i2c1_config, i2c1_alt, ARRAY_SIZE(i2c1_alt));
    
    fnBMP280_Init(); //initiate this driver in i2c1 default pinout and works fine
    
    if (!device_is_ready(eeprom_i2c.bus)) // initiate the device to read in i2c1 alternative pinout
        LOG_INF("I2C bus %s is not ready!\n\r",eeprom_i2c.bus->name);
    
    struct pinctrl_dev_config *i2c1_config =
			PINCTRL_DT_DEV_CONFIG_GET(DT_NODELABEL(i2c1));

	pinctrl_update_states(i2c1_config, i2c1_alt, ARRAY_SIZE(i2c1_alt));
	
    int ret;
    uint8_t u8_reg = 0
    uint8_t pu8_reg_data[6];
    
    ret = i2c_burst_read_dt(&eeprom_i2c,0,&pu8_reg_data[0],6);
    if(ret != 0){
        printk("Failed to read from I2C device address %x at Reg. %x n", eeprom_i2c.addr,u8_reg);
    }
}

Using this code, when I try to communicate with the eeprom_i2c device I get the error "i2c_nrf_twim: Error 0x0BAE0001 occurred for message 0.

Priyanka , can you help me with these problems?

[Priyanka]

Hi Rodrigo,

I see that you have another ticket for the same issue with my colleague and are getting support there. Please continue the conversation there.

-Priyanka

[Viral Patel]

Hi, can you attach a link to the issue here