Add a minimalist implemention of the 'cu' terminal program (part of Taylor UUCP for ages). Using it, you can simply open a serial port and interact with it. Using '~.' you can leave the terminal program and drop back to nsh.

This might  come in handy for other people that have e.g. GSM modems, GPS receivers or other devices with text based serial communications attached to their Nuttx systems.

system/Kconfig

@@ -11,6 +11,10 @@ menu "EMACS-like Command Line Editor"
 source "$APPSDIR/system/cle/Kconfig"
 endmenu
 
+menu "CU Minimal Terminal"
+source "$APPSDIR/system/cu/Kconfig"
+endmenu
+
 menu "FLASH Program Installation"
 source "$APPSDIR/system/install/Kconfig"
 endmenu

system/Make.defs

@@ -42,6 +42,10 @@ ifeq ($(CONFIG_SYSTEM_COMPOSITE),y)
 CONFIGURED_APPS += system/composite
 endif
 
+ifeq ($(CONFIG_SYSTEM_CUTERM),y)
+CONFIGURED_APPS += system/cu
+endif
+
 ifeq ($(CONFIG_SYSTEM_FREE),y)
 CONFIGURED_APPS += system/free
 endif

system/Makefile

@@ -35,9 +35,9 @@
 
 -include $(TOPDIR)/.config	# Current configuration
 
-# Sub-directories containing system task
+# Sub-directories containing system tasks/libraries
 
-SUBDIRS  = cdcacm cle composite flash_eraseall free i2c hex2bin inifile
+SUBDIRS  = cdcacm cle composite cu flash_eraseall free i2c hex2bin inifile
 SUBDIRS += install mdio nxplayer poweroff ramtest ramtron readline sdcard
 SUBDIRS += stackmonitor sudoku sysinfo usbmonitor usbmsc vi zmodem
 

system/cu/Kconfig

@@ -15,3 +15,19 @@ config SYSTEM_CUTERM
 		This terminal might come in handy for other people that have e.g. GS
 		modems, GPS receivers or other devices with text based serial
 		communications attached to their Nuttx systems.
+
+if SYSTEM_CUTERM
+
+config SYSTEM_CUTERM_STACKSIZE
+	int "CU terminal stack size"
+	default 2048
+	---help---
+		This is the stack size that will be used when starting the CU terminal.
+
+config SYSTEM_CUTERM_PRIORITY
+	int "CU terminal priority"
+	default 100
+	---help---
+		This is the task priority that will be used when starting the CU terminal.
+
+endif # SYSTEM_CUTERM

system/cu/Makefile

@@ -1,7 +1,7 @@
 ############################################################################
-# apps/examples/cu/Makefile
+# apps/sysem/cu/Makefile
 #
-#   Copyright (C) 2011-2013 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2014 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -37,7 +37,7 @@
 -include $(TOPDIR)/Make.defs
 include $(APPDIR)/Make.defs
 
-# USB terminal example
+# Minimal CU terminal
 
 ASRCS =
 CSRCS =
@@ -77,9 +77,12 @@ ROOTDEPPATH = --dep-path .
 
 # Built-in application info
 
+CONFIG_SYSTEM_CUTERM_STACKSIZE ?= 2048
+CONFIG_SYSTEM_CUTERM_PRIORITY ?= SCHED_PRIORITY_DEFAULT
+
 APPNAME  = cu
-PRIORITY = SCHED_PRIORITY_DEFAULT
-STACKSIZE = 2048
+PRIORITY = $(CONFIG_SYSTEM_CUTERM_PRIORITY)
+STACKSIZE = $(CONFIG_SYSTEM_CUTERM_STACKSIZE)
 
 # Common build
 

system/cu/cu_main.c

@@ -1,5 +1,5 @@
 /****************************************************************************
- * examples/cu/cu_main.c
+ * system/cu/cu_main.c
  *
  *   Copyright (C) 2014 sysmocom - s.f.m.c. GmbH. All rights reserved.
  *   Author: Harald Welte <hwelte@sysmocom.de>
@@ -313,7 +313,7 @@ int cu_main(int argc, FAR char *argv[])
           case 'r':
             rtscts = 0;
             break;
-            
+
           case '?':
             print_help();
             return EXIT_SUCCESS;