I am trying to use UART1 on nRF52840 to communicate with another device on a custom board. I am using Zephyr. I have successfully compiled code using the function uart_poll_out() and that works for sending one character at a time. However, when I try to call the functions uart_callback_set() and uart_tx() to send several bytes at a time, I get the following linking errors at build time:
....../ncs/v1.3.0/toolchain/opt/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/bin/ld.exe: app/libapp.a(main.c.obj): in function `main':
1> ......\build_nrf52840dk_nrf52840/../src/main.c:85: undefined reference to `uart_callback_set'
1> ....../ncs/v1.3.0/toolchain/opt/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/bin/ld.exe: app/libapp.a(main.c.obj): in function `uart_tx':
1> ......\build_nrf52840dk_nrf52840/zephyr/include/generated/syscalls/uart.h:33: undefined reference to `z_impl_uart_tx'
1> collect2.exe: error: ld returned 1 exit status
The linker clearly can't find the functions uart_callback_set and z_impl_uart_tx, but I don't know what to do to make those functions available to the linker, especially since the function uart_poll_out does work. Code below:
/*
* Copyright (c) 2015-2016 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/types.h>
#include <stddef.h>
#include <errno.h>
#include <zephyr.h>
#include <sys/printk.h>
#include <device.h>
#include <gpio.h>
#include <uart.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
#include <bluetooth/conn.h>
#include <bluetooth/uuid.h>
#include <bluetooth/gatt.h>
#include <sys/byteorder.h>
//this will serve as the link between BLE and WIFI modules
struct device* uart1dev;
void uartTXCallback(struct device *dev, struct uart_event evt, void *user_data){
//called after TX
}
bool sendAT(u32_t* buffer){
//this is the function that will format the AT command and send it
return true;
}
void main(void){
uint8_t testBuffer[] = {'A','T','\r','\n'};
size_t bufLen = sizeof(testBuffer);
int32_t TXtimeout = 100;
//set up UART1:
uart1dev = device_get_binding(DT_LABEL(DT_NODELABEL(uart1)));
uart_callback_set(uart1dev, uartTXCallback, NULL);
while(1){
uart_tx(uart1dev, testBuffer, bufLen, TXtimeout);
//for(int i = 0; i<bufLen; ++i)
// uart_poll_out(uart1dev, testBuffer[i]);
k_busy_wait(200000);
}
}
