A development system for μClinux consists of the following elements:
Each element of the development system is discussed below.
There are several options available for the target hardware, one of which is the STAMP board. This document will focus on this particular target hardware. The STAMP board contains an Ethernet interface with an RJ45 (female) jack, a serial port interface with a DB9 (female) connector, a power supply jack and voltage regulator, as well as several interfaces to various Blackfin peripherals. The Ethernet interface and the serial port are of particular interest because they are normally used as a normaly component of the development system as the interconnect between the target and the development workstation.
The resident software on the target board can consist of Das U‑Boot and/or μClinux. After installing U‑Boot it will reside in flash memory on the target system. U‑Boot can then load μClinux into RAM via a serial or Ethernet connection.
The second element of the development environment is the workstation. This is essentially a Linux PC which should have an available serial port, terminal emulator software, and an Ethernet card. A machine running Windows may also be used as a development workstation as a CoLinux port of the Blackfin tool chain is available. This CoLinux port of the tool chain enables most of the Linux procedures to be preformed from a Windows environment. When OS specific procedures, such as setting up a TFTP server, are encountered instructions for both Windows and Linux operating systems will be given. The software for the target device (e.g. U-Boot, μClinux, etc.) will be compiled on the development workstation by using the Blackfin tool chain. As the architectures of the development workstation and the target hardware are different (the former is usually an x86 like architecture while the latter is the Blackfin architecture), this is referred to as cross compiling. Before software for the target system can be compiled, the Blackfin tool chain must be installed on the development or host workstation.
Once the Blackfin tool chain has been installed on the development workstation an interconnection between the workstation and the target hardware must be established. This interconnection will be used to load programs onto the target system and interact with programs running on the target system. There are two main methods of connecting the workstation and the target system, an Ethernet connection and a serial connection. The Ethernet connection is provided via the RJ-45 connector on the STAMP board. By connecting both the target system and the development workstation to a Local Area Network (LAN), communication between the two machines may be established. Alternately, an Ethernet crossover cable may be connected directly between the target system and the workstation. There are several ways this Ethernet connection may be used: U‑Boot can load μClinux, gdb can debug programs on the target, and μClinux programs such as ftp and telnet can communicate with other network devices.
The serial connection, the other main method of interconnection, is established by connecting a serial cable between a serial port on the development workstation and the DB9 connector on the STAMP board. A terminal emulator program on the workstation is then used to communicate with the target device. For more information on setting up a terminal program see the Terminal Programs page. The serial port is used for standard input and output in U‑Boot and μClinux. gdb may also use the serial port for debugging programs on the target. Also, if a network connection is unavailable, U‑Boot can load μClinux through the serial port, though this is much slower than using the Ethernet connection.