Read registers out of npm1300 from nrf sdk

[e_engineer]

I have a board with the npm1300 and a nrf58240.  I'm trying to read some status registers out of the npm1300 to debug some trouble we are having with it. It doesn't seem to recover from battery voltages around 2.6V -2.8V so I want to see the errors and status. 

I read the doc, i see it's a 16bit addressesing scheme where the first part is the offset and the second part is the register address.  So to read BCHGCONFIG for example which is 0x3C and has a offset "I think" of 0x300 based on the datasheet (it's not really clear).  To read that I think I need to do a 16bit read from 0x033C.

Today my code looks like this and always returns true, and gives me 0 for my data:

// Function to read a 16-bit register from the nPM1300
bool read_npm1300_register_16bit(uint16_t register_address, uint8_t *destination) {
    uint8_t w_addr[2];
    
    // Split the 16-bit register address into two bytes
    w_addr[0] = (register_address >> 8) & 0xFF;  // High byte
    w_addr[1] = register_address & 0xFF;          // Low byte

    // Write the 16-bit register address
    int ret = i2c_write(dev_i2c.bus, w_addr, sizeof(w_addr), NPM1300_ADDR);
    if (ret != 0) {
        printk("Failed to write register address: %d\n", ret);
        return false;
    }

    // Read the 8-bit data from the register
    ret = i2c_read(dev_i2c.bus, destination, 1, NPM1300_ADDR);
    if (ret != 0) {
        printk("Failed to read data: %d\n", ret);
        return false;
    }

    return true;
}

#define NPM1300_ADDR 0x6B  // 7-bit I2C address for nPM1300

and we call in main like this:
// Read from nPM1300
    uint16_t reg_addr = 0x033C;  // Example register address
    uint8_t reg_data;


	for (;;) {
		//printk("Thump!\n");
		bool success = read_npm1300_register_16bit(reg_addr, &reg_data);
		if (success) {
			printk("Read register 0x%04x from nPM1300: 0x%02x\n", reg_addr, reg_data);
		} else {
			printk("Failed to read register 0x%04x from nPM1300\n", reg_addr);
		}
		//dk_set_led(RUN_STATUS_LED, (++blink_status) % 2);
		//dk_set_led(1, (++blink_status) % 2);
		k_sleep(K_MSEC(RUN_LED_BLINK_INTERVAL));
	}
	
	Any advice on how to get this working would be appreaciated. I should mention charging seems to work fine, we added that with an overlay so I assume the TWI is okay.

[Michal]

Hello,

I will look more into it and get back to you tomorrow. You can also take a look into the PMIC drivers, for example by debugging one of the nPM1300 samples.

Best regards,

Michal

[Michal]

Please take a look at zephyr/drivers/mfd/mfd_npm1300.c for more details.

For example:

int mfd_npm1300_reg_write(const struct device *dev, uint8_t base, uint8_t offset, uint8_t data)
{
	const struct mfd_npm1300_config *config = dev->config;
	uint8_t buff[] = {base, offset, data};

	return i2c_write_dt(&config->i2c, buff, sizeof(buff));
}

And in zephyr/drivers/regulator/regulator_npm1300.c you can find the list of some offset defines as well.

Best regards,

Michal

[dacr]

Hi! Is npm1300 powered by anything else apart from battery? If not, as soon as battery voltage goes below POF(2.7V typ), nPM1300 will reset, and will not power back up until VBAT>VBATPOR (2.75V typ), hence any I2C read would return 0 as data.

[cjh39]

I'm also trying to communicate with the npm1300-CAAA, were you able to get any response from the I2C communications ? We are simply trying to read the status register, the battery voltage, and need to put it into ship mode. Our device is running, so I dont think the npm1300-CAAA is in some sort of low power mode.