Copying files to NuttX over serial (the slow way)

Some years ago I show it was possible to copy files to Linux over serial without using zmodem or other protocol: https://acassis.wordpress.com/2012/10/21/how-to-transfer-files-to-a-linux-embedded-system-over-serial/

Today I faced a similar issue, I need to copy a file from host computer to NuttX over serial without using zmodem support.

Then I created a simple 48 bytes file on Linux side and ran these commands on NuttX console (using minicom) :

NuttShell (NSH)                                                                                 
nsh> mount -t vfat /dev/sda /mnt                                
                                
nsh> dd if=/dev/console of=/mnt/test.txt bs=16 count=3                                         

Now on minicom type: Ctrl + A – Y to select a file to paste.

It worked fine, see:

nsh> ls -l /mnt
/mnt:
 -rw-rw-rw-      48 test.txt
nsh> 
nsh> cat /mnt/test.txt
This is a small test!
Just to prove the idea!!!

Now I decided to send a bigger file (4KiB) :

I used the COPYING file of NuttX, just cutting it to 4KiB:

$ sudo dd if=COPYING of=/COPYING bs=1 count=4096

Then on minicom:

nsh> dd if=/dev/console of=/mnt/COPYING bs=64 count=64                                          

Ctrl + A - Y

After selecting the file I noticed that the TXD LED on USB/Serial adapter was blinking at each 1 second. So after about 64 seconds it transfered the 4KiB file.

nsh> ls -l /mnt
/mnt:
 -rw-rw-rw-      48 test.txt
 -rw-rw-rw-    4096 COPYING

nsh> cat /mnt/COPYING
COPYING -- Describes the terms under which Nuttx is distributed. A
copy of the BSD-style licensing is included in this file. In my
words -- I believe that you should free to use NuttX in any
environment, private, private, commercial, open, closed, etc.
provided only that you repect the modest copyright notices as
...
uIP
^^^

Many lower-level networking components of NuttX derive from uIP which
has a similar BSD style

That is it! It is not the faster transfer solution but it proved to work.
I think this same approach should have worked on Linux at that time.

• NuttX