Developing software for JStamp involves writing Java programs. Unlike most PCs and workstations, however, JStamp has no keyboard or display. This means that programs written for JStamp must be written using another computer and subsequently loaded on to JStamp. Writing Java programs on PCs and workstations is a fairly well understood task, but how are programs loaded on to JStamp?
Loading programs on to JStamp is a two-step process. Because the JStamp is based on the aJ-80 processor, the process of loading programs on to the JStamp is similar to the process of loading programs on to any computer based on an aJile processor. Two tools are provided by aJile to load programs on to aJile processor based systems: JEMBuilder and Charade. These two tools are very sophisticated so only a brief overview of them is provided here. Note that these two tools are undergoing improvement and integration. The descriptions provided here are current as of June 2001, but by the time you read this these tools may well be completely integrated with your Java IDE.
As of this writing, the aJile libraries do not support dynamic class loading and linking. Programs loaded on to the aJile processors, including the JStamp, must therefore have all their classes linked prior to runtime. This is JEMBuilder's main tasks. JEMBuilder is also used to configure various hardware options within the aJ-80 such that when the program is loaded and the system restarted, JStamp will be configured as desired. The output of JEMBuilder is a binary file suitable for loading onto JStamp, a load script for Charade, and various other files useful for debugging.
Charade is used to transfer the binary file produced by JEMBuilder onto JStamp. It can also be used for symbolic and low-level debugging of the code running on JStamp. Charade communicates with the aJile based system via a special cable connected between the development system's parallel-port and JStamp JTAG port. This cable is called, not surprisingly, a JTAG cable.