PIC18 Simulator IDE
Help Topics

• General info
PIC18 Simulator IDE is powerful application that supplies Microchip microcontroller users with user-friendly graphical development environment for Windows with integrated simulator (emulator), pic basic compiler, assembler, disassembler and debugger. PIC18 Simulator IDE is designed to be used for the microcontrollers (MCUs) from the Microchip 8-bit PIC18 architecture product line (selected PIC18F models).

The main application window shows all PIC microcontroller internal registers status, mnemonics of the last executed instruction, mnemonics of the next instruction that will be executed, clock cycles and instructions counter and real time duration of the simulation.

• File menu
- Clear Memory
This command will reset simulator to the initial state and clear FLASH program memory and EEPROM data memory working buffers.
- Load Program
This command loads program file into PIC18 Simulator FLASH program memory buffer. The program file must be in Intel HEX format. Default extension is HEX. If present in the HEX file, configuration bytes and EEPROM memory data will also be loaded into working buffers. Once loaded program file can be quickly reloaded by clicking on its location field on the main program interface or by keyboard shortcut SPACE.
- Save Memory
With this command it is possible to save the contents of the FLASH program memory and EEPROM data memory working buffers to a HEX file.

• Simulation menu
- Start
PIC18 Simulator IDE enters simulation mode and begins the execution of instructions starting from the 000000H program memory location.
- Step
This command is enabled only when Step By Step simulation rate is selected. Next instruction is executed on every click on keyboard shortcut F2.
- Stop
PIC18 Simulator IDE exits simulation mode and presents the information about the total number of executed instructions, duration of the simulation and total real time duration of the simulation in clock cycles and µs on PIC microcontroller level.
- Run To Next BASIC Statement
This command is available for programs generated by integrated Basic compiler. It will start Extremely Fast simulation until the next Basic statement is reached and then automatically switch to Step By Step mode. Keyboard shortcut is F4. When available in Step By Step simulation rate, this command will also appear as a new main menu item on the program interface.

• Rate menu
It enables user to change the simulation rate. It is accessible during the simulation, also.
- Step By Step
The interval between consecutive instructions is at user will. When the simulator is in Step By Step mode, it is possible to change the values in all special function and general purpose registers, program counter and working register, by clicking on the appropriate name or value field on the program interface. The value in the SFR registers can be changed alternatively by toggling individual bits of the graphical representation and this feature can be used also with other simulation rates. When this simulation rate is selected new main menu item 'STEP' will appear on the program interface. That will enable an easy access to Step command from the Simulation menu.
- Slow
The interval is 1500 ms.
- Normal
The interval is 250 ms.
- Fast
The interval is around 50 ms.
- Extremely Fast
The interval is very short and is linearly dependent on the overall computer performance.
- Ultimate
The main simulator window is not continuously refreshed after every simulated instruction that significantly improve the simulation performance. The refresh interval can be changed using Change Ultimate Rate Refresh Interval command in Options menu.

• Tools menu
- BASIC Compiler
Integrated BASIC compiler editor window will be opened. More information available in BASIC Compiler Reference Manual. It can be accessed from the Help menu of the main application window or from the BASIC compiler editor window.
- Microcontroller View
This command will open the window with the selected PIC microcontroller pinout. Logical states on all I/O pins is graphically displayed, and can be manually changed on the input pins by clicking on the appropriate toggle buttons. It is possible to change analog values on all I/O pins configured as analog inputs. If this window is opened, it will be refreshed during the simulation.
- Alternative SFR Viewer
This command opens an alternative viewer window for special function registers that can be resized.
- Program Memory Editor
This is access to PIC18 Simulator FLASH program memory buffer editor. It is possible to manually enter instruction opcode by clicking on the display line of the target location.
- EEPROM Memory Editor
This opens PIC18 Simulator data EEPROM memory buffer editor. If this window is opened, it will be refreshed during the simulation. The value in the specific data memory location can be changed by clicking on it.
- Hardware Stack Editor
This command will open the PIC18 Simulator hardware stack buffer editor. If this window is opened, it will be refreshed during the simulation. It also features changing the value of the stack pointer and the values stored on the stack levels.
- Assembler
This command starts integrated assembler. Assembler source files can be edited, assembled and finally loaded into the simulator memory in the same graphical environment. Default extension is ASM. After the successful assembly process the internal assembler will generate two new files. One with HEX extension that is program file in Intel HEX format and that can be directly loaded into the microcontroller program memory, and the other with LST extension that is assembler listing used by the debugger. Configuration word and EEPROM memory buffers are also saved in the generated HEX file. These buffers can be accessed and edited from the Options menu of the Assembler window. More info can be found at the bottom of this file.
- Disassembler
PIC18 Simulator IDE has internal disassembler that is started by this command. The disassembling process is automatically initiated by opening this window. The disassembler will always start from the address 000000H. After the operation is completed disassembler will display the output listing file. The generated listing can be saved to disk. User will be prompted to enter the name for the output file. Default extension is LST.
- Breakpoints Manager
This command starts integrated debugger that can be used to debug and monitor the program execution. The debugger listing file of the program in memory can be generated using internal assembler listing file (if it exists) or by internal disassembler. It is possible to define up to 10 breakpoints by clicking on individual lines in the loaded program listing. When the simulation starts in faster rate modes it will automatically switch to Step By Step mode when reaching any of these breakpoints. The breakpoints are marked by red circles, and the current value of the PC register is marked by yellow arrow. There is an option to keep the PC pointer in focus during the simulation.
- Special Breakpoints
This simulation tool provides the feature to define special breakpoints that will switch the simulation rate to Step By Step mode when the value of the predefined register has changed or reached the predefined value. Up to 5 special breakpoints can be defined to be simultaneously active.
- Interactive Assembler Editor
This command starts integrated graphical tool that will enable beginners to write their first assembler routines interactively without having to memorize the mnemonics of individual instructions from microcontroller instruction set. This is a great tool for educational purposes.
- 8 x LED Board
This simple simulation module can be used to attach up to eight LEDs to microcontroller pins. The color of each diode can be changed by clicking on the LED color field and the pin assignment can be changed by clicking on the label showing the current pin selection.
- Keypad Matrix
This is another simple simulation module for up to 4x4 keypad matrix. The pin assignments can be changed by clicking on the appropriate pin labels.
- LCD Module
This command starts integrated LCD Module simulator. Before it can be used for simulation, user should set up the interface parameters from the Setup dialog.
- Graphical 128x64 LCD Module
This command starts integrated graphical 128x64 LCD Module simulator. Before it can be used for simulation, user should set up the interface parameters from the Setup dialog.
- Stepper Motor Phase Simulation
This simulation tool will show simplified (2-pole) graphical presentation of a unipolar stepper motor phases in both full-step and half-step modes. During the simulation Step Counter field will display the current absolute rotor position measured in steps from the first well-defined rotor position.
- I2C EEPROM
This command starts integrated simulation module for external I2C EEPROMs from 24C family.
- Hardware UART Simulation Interface
This command opens interface for hardware UART simulator.
- PC's Serial Port Terminal
This is an integrated tool that is independent from the simulator. This terminal is connected to PC's serial port and can be used for communication with a real microcontroller for the purpose of serial communication routines testing. Comm port number and baud rate can be set using appropriate commands from the menu.
- Software UART Simulation Interface
This command opens interface for software UART simulator. It is a serial device that can communicate with the microcontroller running software implemented UART routines (SERIN, SERININV, SEROUT and SEROUTINV statements) using real-time serial communication simulated on RX and TX pins.
- Oscilloscope
This is a very useful integrated tool for tracking logic levels on microcontroller pins during the simulation. It is a four channel digital oscilloscope. User can assign target pins to the oscilloscope channels and change the length of the display interval using commands from the Settings menu. Input and output pins are painted with different colors that are user selected. If Pull-up option is selected for an oscilloscope channel, upon transition from output to input pin state, the pin will be set to high default logic level.
- Signal Generator
With this simulation tool user can define up to four independent continuous pulses generators with selectable target input pins, pulse periods and duty cycles. Suitable animation will show the current phase of each pulse generation.
- 7-Segment LED Displays Panel
This integrated simulation tool enables user to define connection with up to four 7-segment LED displays. The connection definition includes pin assignments for all display segments and one enable line to control display selection when more than one display is used with parallel connection of segments - multiplexing. Active levels for all connection lines can be inverted to suit hardware requirements. There is also an option to change the color used to paint the active LEDs on the displays and Keep Last Display option to simulate slow eye response effect for programs that use multiplexing displays.
- Watch Variables
During the simulation of programs written using integrated basic compiler, this tool can be used to watch the current values of all variables declared in the simulated basic program. It is also possible to add user defined variables to the list to monitor other memory locations of interest during the simulation. This feature is useful for memory monitoring for simulated program files, that are not compiled with the integrated basic compiler. User added variables will be remembered between sessions as long as the same program file is loaded in the simulator. Variables from the watch list can be easily removed with the Delete Variable command, so the list can contain variables of special interest only. Other commands and options include: Change Variable Value (can be also started by a single-click on the variable from the list), Display HEX Values, Confirm Delete.
- DS1820 Digital Thermometer
This is a tool for the simulation of programs communicating with a DS18S20 or DS18B20 device using the 1-wire protocol. It shows internal device ROM and SRAM scratchpad memory and features functional CRC generator. The user can change the device type, set the 1-wire interface pin, the temperature that will be measured by the device, along with the temperature conversion time that will be used for the purpose of simulation. The module does not simulate all available ROM and Function commands. The list of the simulated commands can be viewed by clicking the info button.
- Modbus Simulation Device
With this simulation tool user can monitor and interfere with the Modbus firmware running in the simulator and compiled by the integrated basic compiler. More info available in the Basic Compiler Reference Manual.
- PID Controller Process Simulator
This tool can be used to effectively simulate the real operation and the auto tuning feature of the PID controller that is implemented using the OshonSoft PID Controller and PID Auto Tuning libraries for the OshonSoft basic compilers.
Detailed information is available by clicking on the Info label in the Setup dialog, and on the dedicated page on the website.
- External Modules
This tool should be used to establish automation interface with up to five external client/server modules. It is required to enter the class name supplied by external device in the form ApplicationName.ObjectName in order to establish connection with it. External client/server applications will be started and terminated automatically with PIC18 Simulator IDE. More information available in External Modules Manual. It can be accessed from the Help menu of the main application window.

• Options menu
- Select Microcontroller
This command is used to change the microcontroller model to be used in the IDE. It will reset the application to the initial state.
- Change Clock Frequency
This command allows user to change the frequency parameter that is used for the calculation of the real time duration of the simulation. The entered value in MHz is remembered for the future sessions. This parameter is also used by a number of statements in BASIC compiler that use some form of timing routines (WaitMs, WaitUs, Serin, Serout, ...). The default value is 8 MHz.
- Configuration Bits
This option should be used to change the default settings for the configuration bits. That information will be saved in all HEX files generated by integrated assembler. This option is also available in the menu of the assembler window.
- Shortcuts Panel Configuration
This option command opens an easy to use interface for turning on and customizing the fancy-looking shortcuts panel on the main IDE window, for an easy access to the most frequently used menu commands. The panel can contain up to three lines of menu item shortcuts. All main IDE window menu items are available to be placed on the panel.
- Save Positions
With this option selected, the positions of the windows on the screen will be remembered.
- Save Always On Top
With this option selected, the Always On Top setting for all of the windows with this feature will be remembered.
- Auto Start Options
With this utility users can define actions that will be performed on the application startup. These actions include automatic opening of various tools and simulation interfaces from the Tools menu and automatic loading of the last used files in the simulator, assembler and basic compiler.
- Reset Simulation Statistics
This command will set to zero clock cycles counter, instructions counter and real time duration of the simulation. This command can be used to determine the duration of the specific portion of simulated program.
- Change EEPROM Write Time
This command is used to change the number of clock cycles that will be used for the EEPROM write interval. The realistic value is around 5ms. The default value is 1000 clock cycles.
- Change A/D Conversion Time
This command is used to change the number of clock cycles that will be used for the A/D conversion time. The setting in the ADCON0 register is ignored by the simulator. The default value is 100 clock cycles.
- Change UART Transmit/Receive Time
This command is used to change the number of clock cycles that will be used for the UART transmit/receive time by internal hardware UART simulator. The realistic value depends on the defined baud rate. The default value is 1000 clock cycles.
- Change FLASH/EEPROM Unprogrammed Value
This command is used to change the unprogrammed bit values for FLASH program memory and data EEPROM memory from 1 to 0, and vice versa from 0 to 1. If unprogrammed bit value is 1 then unprogrammed FLASH location and unprogrammed EEPROM location will contain FFh. If unprogrammed bit value is 0 then all unprogrammed memory will be filled with zeros.
- Compact Microcontroller View
If this option is turned on Microcontroller View windows will be displayed in more compact form.
- Infinite Loop Stops Simulation
Checking this option will force the simulator to automatically stop the simulation when an infinite loop is encountered.
- Basic Program Tracking
Currently simulated basic statement will appear highlighted in Basic compiler window when this option is enabled.
- Show Confirmation Boxes
When this option is enabled the confirmation boxes showing results of operations will be displayed and will require user response to be closed.
- Preserve Input States on Simulation Start
If this option is enabled then the states of digital and analog inputs on the Microcontroller View window will not be reset to OFF digital state and zero analog value when the simulation is started again.
- Use Voltage for Analog Inputs
Use this option if you prefer to see voltage value (0.00V-5.00V) instead of raw analog value (0-1023) for analog input states in Microcontroller View windows.
- Continuous Analog Input Slider Update
If this option is enabled then the analog input values will be continuously updated with scrolling of the analog input slider in the Microcontroller View window. Otherwise, the update will occur on the closing of analog slider pop-up only.
- Change Ultimate Rate Refresh Interval
This command allows user to change the refresh interval (in milliseconds) for the main simulation interface when the simulation is running at Ultimate rate. Its value however does not affect the simulation performance considerably. The default value is 500ms.
- Editor Setup
With this setup tool it is possible to change various properties of basic compiler and assembler code editors.
- Change Color Theme
This command will open a dialog with the rich list of available color themes, so that user can change application appearance.

• Help menu
- Help Topics
This command will display Help Topics. This help file contains general information about the application with description of all menu items.
Help viewer window features navigation panel showing topics and subtopics of the displayed help file. Right-click on the navigation panel will show pop-up menu with Show All Subtopics and Hide All Subtopics commands. Single-click on the item from the navigation panel will move focus on the display panel to the appropriate position. Double-click on the topic item will show/hide its subtopics. The display panel shows the content of the loaded help file. Right-click will display pop-up menu containing various options and commands including: Copy, Copy RTF, Copy HTML, Print, Font Increase, Font Decrease, Font Reset, Always On Top. Help viewer window is resizable and will remember both its position and size. The vertical separator between navigation and display panels is moveable and its position will also be saved after the viewer is closed.
- BASIC Compiler Reference Manual
BASIC Compiler Reference Manual will be displayed in the help viewer.
- External Modules Manual
External Modules Manual will be displayed in the help viewer.
- Check For Updates
This tool will enable user to establish connection with OshonSoft.com website to check out if there is a new software release available for download. Version log file will be displayed after the response from the website has been received.
- Bug Report Interface
This interface should be used to send the reports about possible bugs in software to OshonSoft.com. In addition to the user written part the full report will contain a part that is generated by software (system report).
- About
This command will display the basic information about the software package.
- View License Information
This command will display the information about the installed license for the software.

• Special notes
- Watchdog Timer is not simulated (CLRWDT instruction is executed as NOP)
- Power-down Mode is not simulated (SLEEP instruction will stop the simulation)
- Extended instruction set is not supported

• Assembler overview
Here is the basic info related to the internal assembler.

Constants
Assembler accepts wide range of formats and notations for the numeric constants:
- characters: "n", 'n', A'n'
- hex numbers: 0xnn, 00h, $nn, &hnn, &nn, H'nn'
- binary numbers: %nnnn, 0bnnnn, nnnnb, B'nnnn'
- decimal numbers: nnn, .nnn, D'nnn'
Numeric constants may contain # prefix.

Directives
Assembler supports the following directives: ORG, EQU, INCLUDE, DB (DEFB), DW (DEFW), DCONF (DEFCONF), BANKSEL and END.
They can also be used with the dot prefix (like .EQU). Additionally, BYTE can be used as the alias for DB, WORD as the alias for DW, #INCLUDE for INCLUDE.
Label is a symbol name for the current memory location counter value.
- ORG directive alters the setting of the location counter.
- EQU directive creates a symbol/label with the value of the given expression.
- INCLUDE directives can be used to insert code from external ASM files. They can be nested with no limitations.
- DB directive initializes memory with one or more byte values.
- DW directive initializes memory with one or more word (2-byte) values.
For DB and DW, multiple expressions separated by commas may be specified. Strings are also accepted. There is no limit for the number of arguments.
- DCONF directive prepares the configuration setting values that will be used to override the defaults.
- BANKSEL directive generates the code to select the appropriate bank for the specified register.
- END directive marks the end of the source file.
= will be recognized as the EQU directive.

Expressions
Numeric argument can contain the arithmetic operations (+,-,*,/,\) and the bitwise logical and shift operations (&,|,^,<<,>>).
Parentheses in the expression are also supported. The assembler is able to evaluate any expression, no matter how complicated it is.
This is the list of binary operators based on the increasing precedence implemented: |,^,&,(<<,>>),(+,-),(*,/,\).
The prefixes high (>) and low (<) can be used to return high byte and low byte of the 16-bit numeric argument.
The assembler can work with the full range of the unsigned 4-byte integer values, so loww and highw prefixes are also available to return the low and high words of the argument.
All the prefixes are treated as unary operators by the expression evaluation engine.
PC and $ symbols can be used to represent the absolute address of the line of code (the location counter value).

Here is one test example:
   lab1    equ 100*2  ;C8
           lab2 equ 0x1264
   lab3    = 2
   lab4    equ 0x2345
           movlw lab1-0x10
           movlw 0x55
           movlw <lab2
           movlw 55h^0xfe+1
           movlw $55
           movlw h'55'
           movlw -1
           movlw -lab3
           movlw 0x55+0x10
           movlw 0x10*8
           movlw 128/lab3
           movlw $-2
           movlw pc+2
           movlw high (0x1234+lab4)
           movlw low lab4
           movlw -0x4-lab3
           movlw high highw 2000000000  ;77359400
           movlw high loww 2000000000  ;77359400
           movlw high loww -1  ;FFFFFFFF
           movlw high highw -1  ;FFFFFFFF
           movlw high loww -2000000000  ;88CA6C00
           movlw high highw -2000000000  ;88CA6C00
           movlw high loww 3000000000  ;B2D05E00
           movlw low highw 3000000000  ;B2D05E00
           movlw high highw 3000000000  ;B2D05E00

Macros
OshonSoft PIC18 Simulator IDE integrated assembler in the current release does not support macros.

MPASMWIN
If better performance is needed, assembler editor can be used as the graphical interface for the external MPASMWIN assembler. It is only necessary to locate the executable file of the external assembler before the first use.