User Interface

RedBoot provides a command line user interface (CLI). At the minimum, this interface is normally available on a serial port on the platform. If more than one serial interface is available, RedBoot is normally configured to try to use any one of the ports for the CLI. Once command input has been received on one port, that port is used exclusively until the board is reset or the channel is manually changed by the user. If the platform has networking capabilities, the RedBoot CLI is also accessible using the telnet access protocol. By default, RedBoot runs telnet on port TCP/9000, but this is configurable and/or settable by the user.

RedBoot also contains a set of GDB "stubs", consisting of code which supports the GDB remote protocol. GDB stub mode is automatically invoked when the '$' character appears anywhere on a command line unless escaped using the '\' character. The platform will remain in GDB stub mode until explicitly disconnected (via the GDB protocol). The GDB stub mode is available regardless of the connection method; either serial or network. Note that if a GDB connection is made via the network, then special care must be taken to preserve that connection when running user code. eCos contains special network sharing code to allow for this situation, and can be used as a model if this methodology is required in other OS environments.