How to increase RTT download buffer in Modem Shell

RE: How to increase RTT download buffer in Modem Shell

Håkon Alseth — Mon, 22 Sep 2025 12:13:07 GMT

Hi,

Glad to hear that you found a solution to your problem. What you can also check is the buffering setting on the nRF, specifically this one:

CONFIG_SEGGER_RTT_BUFFER_SIZE_DOWN

RTT is mostly used from nRF->PC, so the buffering from PC->nRF is kept smaller.

Kind regards,

Håkon

RE: How to increase RTT download buffer in Modem Shell

RichM — Fri, 19 Sep 2025 16:54:29 GMT

I actually figured this part out... dice up the output with a little delay between chunks. Still not quite working, but getting closer.

def cmdToRTT(data_to_write):
print ("RTT>>" + data_to_write)
data_to_write = data_to_write + "\n"
byteData_to_write = data_to_write.encode('utf-8')
for i in range(0, len(byteData_to_write), 30):
print (byteData_to_write[i:i+30])
bytesWritten = jlink.rtt_write(0, byteData_to_write[i:i+30])
print (i, bytesWritten," Bytes were written")
time.sleep(1)