Sending CTRL-Z over UART

[frijj2k]

Hi, I have a SIM800L GSM/GPRS module that I can successfully talk to via the UART on the nRF51.

I can tell it to dial numbers etc and that all works fine.

My problem is that to send an SMS, the final character (after inputting the message) needs to be a CTRL-Z sequence. (Dec 26 - Hex 1A)

If I enter the AT commands via a terminal and an FTDI cable, everything is working. But when I try sending the sequence from the nRF51's UART, everything 'looks' good apart from the CTRL-Z character which shows itself as a '.' on my terminal and the SIM800L module ignores it.

I have tried placing the CTRL-Z sequence within my string via sprintf and also I have tried manually sending it at the very end directly via app_uart_put as follows...

err_code = app_uart_put((uint8_t)0x1A);  // CTRL-Z

But this doesn't work.

What am I doing wrong?

Thanks in advance!

[Andrew]

One thing with CoolTerm, you should be able to see the actual hex values of the ascii characters that are coming back. In the view menu, switch it to hex and see what the real value of that (.) is. This should also verify that the header command and tail of the command is terminated correctly. asciitable.com is a good place to have bookmarked for all of the different ascii commands and their hex / decimal values.