Hi Nordic Team,
I am using the nRF52840 microcontroller and have interfaced a modem with one of its UART modules, as my modem communicates with the Nordic chip via UART. The issue I am facing is that even when I completely turn the modem OFF, the UART is still consuming approximately 150 to 200 µA. Specifically, the line CONFIG_SERIAL=y is causing this power consumption. If I disable this line in my proj.conf file, I encounter compilation errors because I am using UART drivers in my project.
Is there a solution to this problem so that the UART only consumes power when the modem is in use? Below are some configurations I am using in my project. Kindly be noted that I have only TX and RX lines of UART.
proj.conf file settings
CONFIG_SERIAL=y
# Power Management
CONFIG_PM=y
CONFIG_PM_DEVICE=y
.dts file settings
.dts file settings
&uart1 {
compatible = "nordic,nrf-uarte";
status = "okay";
current-speed = <115200>;
pinctrl-0 = <&uart1_default>;
pinctrl-1 = <&uart1_sleep>;
pinctrl-names = "default", "sleep";
};
My modem UART Init function along with callback
My modem UART Init function along with callback
// Get the modem device node labeled as uart1
const struct device *modem_dev = DEVICE_DT_GET(DT_NODELABEL(uart1));
int modem_init()
{
int ret;
// Init UART driver for Modem
// printf("Initializing modem\n");
if (!device_is_ready(modem_dev))
{
printf("UART1 is not ready!");
return -1;
}
k_msleep(200);
ret = uart_callback_set(modem_dev, modem_callback, NULL);
if (ret != 0)
{
printf("Failed to set modem callback on UART1 (Error code: %d)\n", ret);
return -2;
}
jsmn_init(&parser);
// Check if the flash device was successfully obtained
if (!device_is_ready(nrf_flash_dev))
{
printf("Nordic nRF5 flash driver was not found!\n");
return -3;
}
}
static void modem_callback(const struct device *dev, struct uart_event *evt, void *user_data)
{
switch (evt->type)
{
case UART_RX_RDY:
break;
case UART_RX_DISABLED:
// Re-enable UART RX to continuously receive responses
// uart_rx_enable(dev, __modem_response_buffer, sizeof(__modem_response_buffer), NULL);
break;
case UART_RX_BUF_REQUEST:
// Provide a new RX buffer for continuous reception
uart_rx_buf_rsp(dev, __modem_response_buffer, sizeof(__modem_response_buffer));
break;
case UART_RX_STOPPED:
break;
case UART_RX_BUF_RELEASED:
break;
default:
break;
}
}