Hitex developed an entirely new emulator design in the AX251 to support
the MCS®251 processor family from Intel. The AX251 incorporates several
innovative features to increase the debugging capability of the design
engineer while keeping the price affordable.
Genuine real-time operation is assured and internal events are visible due to the use of Intel bond-out technology. ROM and ROMless variants are all supported.
Major compiler manufacturers are supported either explicitly or through the Intel OMF251 format.
The Hitex AX251 will provide powerful debugging capabilities and efficiency to speed your 251 designs to completion.
The AX251 supports all operating modes of the 251 processor. Selection of the binary mode (for existing MCS®-51 designs ported to the pin compatible 251) or source mode (for new designs with the more efficient native 251 code) is easily handled with a simple mouse click in the drop-down menus of the popular user interface HiTOP for Windows.
The AX251 also completely supports page and non-page modes, zero wait state operation and EPROM mapping to the overlay memory. All operating modes in the Special Function Registers are displayed in plain English and can easily be changed without the use of obscure binary or hexadecimal codes.
All present MCS®251 derivatives are supported including the MCS®151 and the USB (Universal Serial Bus) parts. Future derivatives are quickly supported by changing the adaptation probe or by modifying a special derivative file. TEMIC derivatives licensed from Intel are also supported. Different package types such as PLCC or the PDIP are emulated with specific adapters for trouble free operation.
The AX251 has a 32 kbyte by 80 bit trace with advanced recording features found only in Hitex emulators. These recording features provide flexible filtering mechanisms to allow the designer to locate problem areas very quickly. The AX251 allows you to select those areas of processor activity of interest. There is no need to search through a large buffer filled with obscure machine cycles to find bugs. Trace information can be recorded and displayed as raw processor cycles, assembly code lines or High Level Lines with comments. A Tag ram-based filter mechanism is used to select only certain areas of memory to be recorded.
Separate 256k Code and data coverage locates dead code and unused data space. Unitialized variables can be detected with this system. The entire address space of the 251 is monitored for complete location of potential problem areas.
Obtaining critical event timings in the integral time stamp system is a simple and effective process. Timing can be saved relating to processor response, interrupt request and program execution times. These time stamps have a resolution of 100 nsec and are saved in the trace continuously. A separate real-time counter can be used to time user-specified events.
The AX251 easily accomplishes advanced statistical analysis of your program. The designer’s program can easily be fine-tuned. HiTOP does this in one example by calculating and displaying how often a code’s execution time fell between certain time limits. Modules, functions or HLL code lines can be selected. The data can be displayed in a tabular form or as a histogram.
The AX251 uses hardware breakpoints that are separate from the triggers for maximum flexibility. The AX251 uses a revolutionary system of breakpoints. Breakpoints can be set for program execution or Data Access areas. These are separate 256K breakpoints that can act on a single address or a range of addresses. Execution breakpoints stop the emulation before executing the instruction where the breakpoint is set. Data Access breakpoints can be set on a variable and whenever that variable is read or written, the breakpoint will react at the next change in program flow.
The extensive trigger system can act on addresses, data and external signals and these can be combined logically. Trace recording, break conditions and time measurement can be controlled with the triggers. Unusual instances are easily located with the Hitex triggers. A word value is properly triggered on even if the processor outputs it as two separate bytes on the external buss.
The Emulation Memory can be mapped to the target hardware to any boundary of 1 Kbyte. This memory can also be used in stand-alone operation for software development before the target system is completed. The emulation memory can be selected on-the-fly and can be watched in real-time with the emulation running.
The emulator connects to the host PC through a standard RS-232 COM at speeds from 9600 to 115 kbaud. The PARA Hitex proprietary parallel card is an economical avenue for faster speeds of up to 250k baud. The new HiNET ethernet interface enables the AX251 to be located on a net as a shared resource node for maximum flexibility.
HiTOP for Windows is the standard user interface used for all Hitex products. This allows designers to move from different emulator models, simulators and monitors with a minimum of effort. HiTOP features include an intuitive interface, full drop-down menus with prompts, context sensitive Help, movable windows, debugging in assembly or High Level language. HiSCRIPT, a script language, is used to create automatic sessions useful for automatic testing of target boards or code. HiTOP runs on Windows 3.1, 95, NT and soon....UNIX.
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