CLI 16 character limit?

[Keith V]

I have a small program that is to be used in production to test my device. It has to be scriptable so I'm using teraterm over rtt.

No external IO for a serial port.

Everything is working great until I try to issue a long command, anything > 16 characters

So 'mfg led all on' is OK but 'mfg led all off' fails. When I press enter the first time I just see a CR, no LF, if I press enter a second time the command works.

if I change the command to 'mfg led all of' it works again!

I've looked through nrf_cli.c but I don't see anything.

SO there looks like a limit of 15 characters?

Oh, so this only happens in teraterm and putty, it works in the Segger IDE and in rtt viewer. So I'm now thinking it's a issue with the terminal programs??

Thanks for any insight

Keith

[Einar Thorsrud]

Hi Keith,

There is not 16 character limit in the CLI. I notice that you only see issues with the UART backend and not the RTT backend, so perhaps there is something related to your UART buffer configuration? Can you share your sdk_config.h so I can see if I spot anything there? Which SDK version are you using?

[Keith V]

I do agree it's likely something in the terminal programs

I'm not using the UART, I'm using putty and teraterm in telnet mode. port 19021

I'm using SDK v17.0.2

Soft device 7.2.0

Here is my sdk_config

3465.sdk_config.h

[Einar Thorsrud]

Aha, so it is all RTT. I thought you were using PuTTY and Tera Term for UART. Then this is really strange, and I do not expect to find an explanation in sdk_config.h.

I gave this a test now, and see the same as you. Using the unmodified CLI example I see the following (erroneous) behavior:

rtt_cli:~$ rtt_cli:~$ print all a b c d e f g h i k
print all a b c
a b c

Using UART (with PuTTY) I get the expected result:

uart_cli:~$ print all a b c d e f g h i k
a b c d e f g h i k

I am not able to explain this at the moment but I will look at it again in Monday.

[Keith V]

Well Thats good

did you see the issue where you have to press enter twice for strings longer that 15 chars too?

[Keith V]

found it, there IS a setting in the sdk_config:

// <o> SEGGER_RTT_CONFIG_BUFFER_SIZE_DOWN - Size of downstream buffer. 
#ifndef SEGGER_RTT_CONFIG_BUFFER_SIZE_DOWN
#define SEGGER_RTT_CONFIG_BUFFER_SIZE_DOWN 16
#endif

Change that to something bigger, I went to 32 and it all works as expected.

I suspect that the RTT viewer does a retry if the max number of characters is hit, while teraterm just throws it over the wall and hopes for the best