HSIM is a DOS based product.

Starting evaluation copy
Open the 'Start : Program : HsimDemo' menu and click on 'Hsim Demo'. Or change to the directory where you have copied files and type 'HSIM' and press Enter. HSIM starts showing its about box.

User Interface
HSIM has overlapping windows interface. HSIM supports mouse. It is highly recommended to use mouse as it is very convenient. If you plan to use mouse you should install mouse driver before starting HSIM.

HSIM opens following windows.
  • 8085 : This window displays internals of 8085 such as registers, flags etc.
  • Memory : This window displays memory of 8085.
  • Program : This window displays assembly program being simulated.
Each device you connect will be displayed in a separate window.

The window shown on top is the selected window. You can select any window by pressing Ctrl+W. This key will open a list of all available windows. You can also switch between windows by pressing F6. You can press F8 to move a window. If you have mouse, click the window you want to select. You can move the window by dragging its border.

Some windows have their own personal menus. Such windows, when selected will show menu icon '[]' on the top left corner. You can open this menu by clicking on the icon or by pressing Alt+Space. This menu may contain some options related to the contents of the window.

Overview of HSIM
HSIM has 3 major components.
  • Circuit Builder
  • Assembler
  • Simulator

Circuit Builder allows you to build a circuit by connecting various devices to microprocessor. You can add a new device (like programmable chips, latches, clock pulse generators etc.) in the circuit by using 'Connect Device' option from 'Circuit' menu. You can connect pins of various devices to each other by using 'Connect Inputs' option from the personal menu of the device window. A circuit can be stored in a circuit-file.

HSIM has built-in assembler. To assemble a file you first need to specify the name of the file by using 'Source File' option from 'Assembler' menu. Now you can assemble the file by using 'Assemble' option from 'Assembler' menu. Assembler will assemble the file to machine code which can be seen in program memory window.

Once you have assembled the program, you can simulate it. The program window will show the instruction pointed by program counter. You can simulate this instruction by pressing 'S'. This will scroll the program window and the next instruction to be simulated will be displayed at the bottom. Simulating instructions will update registers, flags, memory etc. modified by that instruction. These changes can be observed in respective windows. You can run program continuously by pressing 'R'. This will keep on executing instructions one after the other. To stop this continuous execution press Space.

Editing Source File
You can edit the source file by using your own favorite editor within HSIM. To specify the editor use 'External Editor' option from 'Assembler' menu. HSIM will ask you the name of the editor. Type in the full path. Now you can use 'Edit' option from 'Assembler' menu to edit the source file.

Using the SAMPLE
The demo version contains a sample circuit SAMPLE.CKT and corresponding assembly program SAMPLE.ASM. The sample circuit consists of a single 8255 chip connected to 8085. The assembly program puts the 8255 in Bit SetReset mode (Mode 1) and cyclically sets and resets pins of port C.

Use 'Open Circuit' option from 'File' menu to load circuit file SAMPLE.CKT. Use 'Source File' option from 'Assembler' menu to select SAMPLE.ASM. Use 'Assemble' option from 'Assembler' menu to assemble to program. Use 'S' key repeatedly to simulate the program. (You can also press 'R')

The Evaluation copy
Evaluation Copy is a working copy of the software except for few features. The features removed from this copy of HSIM are
  • Simulation of 8155, 8250, 8251, 8253, 8259, 8279, RTC and FILE
  • Simulation of ACALL, LCALL, RET, PUSH, POP
  • Assembling of programs longer than 50 lines
  • INCLUDE directive in assembly programs
  • HEX file interface
  • Memory access addresses 512 and above