how to write simple uart program for sending and receiving data

[ASHISH]

hello there,

i am using nrf51422 but dont know how to write a program for uart. i want to send AT commands to Quectel M95 using uart . good help appriciated!!

cheers, Abhijeet

[ASHISH]

hi, thank for your help but you did not understood my point maybe. I did not send anything on uart i just connected the TX and RX pin of ec25 to nrf51 board and flashed my program(i had set the baudrate to 115200 as per ec25 requirement) after successfully programming my nrf51 board i opened my termite as soon as i opened it was continuously sending "start[00]". And when i removed the TX and RX pin and changed the baudrate to 38400 and restarted the termit then my ble to uart communication was working fine. I want to know how can i make it to communicate with ec25 on baudate 115200.

[Sigurd]

When you use the terminal on the PC, you are probably interfering with the UART connection between the nRF5x and the ec25 if you are using the default UART pins. The UART signals are also routed directly to the interface MCU(on-board Segger J-link). The UART pins connected to the interface MCU are tri-stated when no terminal is connected to the virtual COM port on the computer. I.e. You should not use the PC terminal if you have connected the nRF5x and the ec25 together using UART.

[ASHISH]

HI, we have tried everything that you said and we try to send AT command through mobile but did not get any response from EC25. As you said earlier about "You can then later modify the uart_event_handle() function, so that you send AT commands to the ec25 automatically, based on what the ec25 is sending to the nRF51" could you please send me the changes that i have to make in my code to send AT command.

[Sigurd]

Does the EC25 send something to the nRF51 when it starts up? Is your settings correct? I.e. baud-rate, flow-control, parity, pin numbers is correct? Do you have access to a logic analyzer/scope, so you can see the data sent over the UART lines?

[ASHISH]

Hi there !! could you please explain all the uart example step by step or send me the link where this nrf51 uart example explained correctly..i dont understand functions that are used in this program because i want to send AT commands and receive the desired output..