RE: connect sdk twi startup problems

Simon — Mon, 01 Feb 2021 10:14:08 GMT

One way of going about this is to use the SYS_INIT macro, to get code executed before main. Here are some examples how to go about it:

For a certain board:
- zephyr/boards/arm/nrf5340dk_nrf5340/nrf5340_cpunet_reset.c
- zephyr/boards/arm/nrf52840dongle_nrf52840/board.c
Example of SYS_INIT in the hci_driver for the SoftDevice controller: nrf/subsys/bluetooth/controller/hci_driver.c

Everything in SYS_INIT gets placed in linker sections that the startup code runs at certain points, PRE_KERNEL, POST_KERNEL, etc.: https://github.com/nrfconnect/sdk-zephyr/blob/master/include/init.h#L135

Note that if you use SYS_INIT with PRE_KERNEL priority you will not have access to zephyr's GPIO driver; you may want to use different priority (to make sure GPIO driver is up that would be APPLICATION I think) or use nrfx directly (easiest option).

In upstream Zephyr, you could use the regulator devices to do this:

https://github.com/zephyrproject-rtos/zephyr/blob/bbc563f5ac1cfc507c469ae944b14e75871a79fd/boards/arm/thingy52_nrf52832/thingy52_nrf52832.dts#L69

Also check out: docs.zephyrproject.org/.../regulators.html

Best regards,

Simon

RE: connect sdk twi startup problems

bossssie — Sat, 30 Jan 2021 16:23:49 GMT

Just an update, for now I seem to have "solved" this issue by adding a bit of code to the BME680 to write the GPIO pins high. But this is clearly not the way to go. Does anyone have an idea to make a driver or a piece of code that will run before the sensor startup?

static int pwr_ctrl_init()
{
	const struct device *gpio;
	const char *port = DT_LABEL(DT_NODELABEL(gpio0));
	gpio = device_get_binding(port);
	if (!gpio) {
		printk("Could not bind device \"%s\"\n", port);
		return -ENODEV;
	}

	gpio_pin_configure(gpio, VDD_PWR_CTRL_GPIO_PIN, GPIO_OUTPUT_HIGH);
	gpio_pin_configure(gpio, VDD_PWR_PULLUP_GPIO_PIN, GPIO_OUTPUT_HIGH);

	k_sleep(K_MSEC(10)); /* Wait for the rail to come up and stabilize */

	return 0;
}