Can't reach low power with zephyr's GPIO API

Question

Hi, 
 using nrf connect sdk 3.11, nrf54L15-PDK 
 I am testing low power with development board, I am trying to reach low power 2.9uA as bench marked. 
 When GPIO (button) set with interrupt on evaluation boards ,P1.13 i reach 23uA. 
 uart is disabled. 
 without this GPIO configuration i do reach low power benchmark target. 
 see code snippets to reproduce. 
 Steps: 
 1. I start with a shell example using the uart over USB on eval board. 
 2. call in main 
 
 const struct device * uart = DEVICE_DT_GET ( DT_NODELABEL (uart20));

pm_device_runtime_enable ( uart ); 
 pm_device_runtime_get ( uart ); 
 
 2. configure gpio button as seen in code below 
 3. Turn of UART using a shell command - pm_device_runtime_put(uart) 
 observe that current has reached 20uA. 
 -- when not configuring GPIO as below, eval board reach 2.9uA.

static const struct gpio_dt_spec pad_input_gpio = GPIO_DT_SPEC_GET(DT_NODELABEL(pad_state_in), gpios);

static void button_pressed(const struct device *gpio_dev, struct gpio_callback *cb,
 uint32_t pins)
{
 // blink led
 LOG_INF("GPIOTE event:");
}

void setup_gpio(void)
{
 int ret;
 if (!device_is_ready((pad_input_gpio.port))) 
 {
 LOG_ERR("GPIO controller not ready");
 return -1;
 }

ret = gpio_pin_configure_dt(&pad_input_gpio, GPIO_INPUT | GPIO_PULL_UP);
 if (ret != 0) 
 {
 LOG_ERR("Failed to configure pin (err %d)", ret);
 return -1;
 }
 
 uint32_t pin_mask = 0;
 pin_mask |= BIT(pad_input_gpio.pin);
 gpio_init_callback(&gpio_cb, button_pressed, pin_mask);
 int err = gpio_add_callback(pad_input_gpio.port, &gpio_cb);
 if (err) {
 LOG_ERR("Cannot add callback");
 return err;
 }

gpio_pin_interrupt_configure_dt(&pad_input_gpio, GPIO_INT_EDGE_TO_ACTIVE);
} 
 
 CONFIG_SYS_CLOCK_TICKS_PER_SEC=1000

CONFIG_PM_DEVICE=y
CONFIG_PM_DEVICE_RUNTIME=y
#CONFIG_NRFX_UARTE20=y
#CONFIG_PINCTRL=y
#CONFIG_PINCTRL_NRF=y
#CONFIG_PINCTRL_DYNAMIC=y

# Shell
CONFIG_SHELL=y
CONFIG_SHELL_BACKEND_SERIAL=y
CONFIG_UART_CONSOLE=y

# Logging
CONFIG_LOG=y
CONFIG_LOG_DEFAULT_LEVEL=2
CONFIG_LOG_MODE_MINIMAL=n
#CONFIG_LOG_BACKEND_UART=n
CONFIG_LOG_RUNTIME_FILTERING=y # adds ability to change log levels at runtime
#CONFIG_LOG_MODE_IMMEDIATE=y
CONFIG_LOG_CMDS=y # shell commands
CONFIG_LOG_PRINTK=y

# Bluetooth
CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_NAME="BLE_Advertiser"
CONFIG_BT_DEVICE_APPEARANCE=0
CONFIG_BT_PRIVACY=n
CONFIG_BT_HCI=y

#float support
CONFIG_CBPRINTF_FP_SUPPORT=y # enables float support in printf functions

# external flash
CONFIG_FLASH=y
CONFIG_SPI_NOR_SFDP_RUNTIME=y # enable SFDP support for SPI NOR flash
CONFIG_SPI_NOR=y
CONFIG_SPI_NOR_FLASH_LAYOUT_PAGE_SIZE=4096
CONFIG_FLASH_PAGE_LAYOUT=y # enable flash page layout API 
CONFIG_FLASH_SHELL=y
CONFIG_FLASH_MAP=y

# NVS Filesystem
CONFIG_NVS=y
CONFIG_NVS_LOG_LEVEL_DBG=y
CONFIG_MPU_ALLOW_FLASH_WRITE=y

# Input sub system
CONFIG_INPUT=y
CONFIG_INPUT_EVENT_DUMP=y
CONFIG_INPUT_GPIO_KEYS=n
CONFIG_GPIO=y
CONFIG_LED=y
CONFIG_LED_GPIO=y
#CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS MAX is 12
#CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS=12 
#CONFIG_NRFX_GPIOTE_LOG=y

# NFC
CONFIG_NFC_T4T_NRFXLIB=y
CONFIG_NFC_NDEF=y
CONFIG_NFC_NDEF_MSG=y
CONFIG_NFC_NDEF_RECORD=y
CONFIG_NFC_NDEF_LE_OOB_REC=y
CONFIG_NFC_NDEF_PARSER=y

# HEAP

# CONFIG_PM_PARTITION_SIZE_NVS_STORAGE=0x00

# MAIN TASK MODULE
CONFIG_APP_MAIN_TASK_ENABLED=y
CONFIG_APP_MAIN_TASK_SHORT_QUEUE_LEN=10
CONFIG_APP_MAIN_TASK_MAX_SHORT_MESSAGE_LEN=4
CONFIG_APP_MAIN_TASK_LONG_QUEUE_LEN=4
CONFIG_APP_MAIN_TASK_MAX_LONG_MESSAGE_LEN=128
CONFIG_APP_MAIN_TASK_MAX_NUM_OF_EVENTS=15 
 
 I to tried all GPIO_INT_ defined configuration. all do not help. 
 
 GPIO_INT_EDGE_TO_ACTIVE

GPIO_INT_LEVEL_INACTIVE

GPIO_INT_LEVEL_ACTIVE

GPIO_INT_EDGE_BOTH

GPIO_INT_LEVEL_INACTIVE

gpio_pin_interrupt_configure_dt ( & pad_input_gpio , GPIO_INT_EDGE_TO_INACTIVE );

thanks. 
 Dan

Turbo J · Accepted Answer

Pretty sure this is intended behaviour, but it may not be properly documented . 
 GPIOTE "in" events are more expensive than "port" events. But "port" events only support level detection - your code sets up edge detect which requires "in" event. 
 I can't find documentation on how much current this is supposed to cost extra. 
 Workaround is to use the "sense" mechanism (I believe you can set this up in DT overlay) and "level" triggered GPIO interrupt. 
 Note: Just setting up level triggers for the GPIO int is not enough, the pin must also be set up correctly ( sense-edge-mask ).

Håkon Alseth · Answer

Hi, 
 
 narfster said: a. what is the max number of sense pins i can use. 
 PORT can be used on all capable GPIOs (P0/P1 in this case). 
 narfster said: b. When should developer use sense pins, when should he prefer the default behavior. (not low power) 
 SENSE (using PORT event) is level triggered, as compared to edge-triggered with GPIOTE_IN channel. 
 A GPIOTE IN channel can generate individual events, and can be used to tie it together with other events via DPPI. 
 SENSE (PORT) is usually used for wake-up scenarios, while GPIOTE IN is used for more precise timing. 
 narfster said: c. is there a restriction on what gpio pins to use for sense. i.e. is P2.x supported for GPIOTE sense? 
 On the nRF54Lxx-series devices, you can use GPIOTE SENSE (PORT event) on P0 and P1 based GPIOs, but P2 does not have any sense/GPIOTE functionality: 
 https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/gpio.html#ariaid-title4 
 
 Kind regards, 
 Håkon

Can't reach low power with zephyr's GPIO API

Top Replies