Speed 400 Speed Control

Programming

Programming the microprocessor requires one or more of the following files. They should be renamed as given to work properly.

HEX file: This is the hex programming file for the processor shown on the parts list. It should be stored as "speed400.hex" to work properly with the programmers I know about. It is in Intel HEX format, as defined by Microchip, Inc.
ASM file: This is the assembly language source file. Store it as "speed400.asm".
Include file: This include file should be stored as "speed400.inc". It defines the transformation between servo pulse width and the operation of the speed controller. It is used in speed400.asm.
Table generator: This is a C++ program which generates the include file given above. Store it as "s400tbl.cpp". I believe it should run as a C program, but I haven't tried it.

There are two approaches you can take to programming:

Use the hex file provided to program a one-time programmable device. This requires access to a suitable programmer.
Modify the source files provided to make it do something new. This will not be discussed further; those who undertake such a modification need to know more than I can teach here. Visit the Microchip web site for a lot of good information. If a new include file is needed for a different throttle response and if the user wishes to modify the s400tbl program, he will need a C or C++ compiler, along with the knowledge to use it.

I will describe using the Picstart Plus programmer and the MPLAB development environment to program the devices with the hex file given. I do not have any experience with other programmers.

Start the MPLAB development environment, but do not load a project.
Under the Options menu, select Development Mode. A dialog box will pop up. Select the MPLAB-SIM Simulator button, then select the PIC12C509 processor.
Under the File menu, select Import, then select Download to Memory. A file open dialog box will appear. Locate the speed400.hex file described above, and open it.
Under the Picstart Plus menu, select Enable Programmer. If this fails, look at the Options menu under Programmer Options. Verify that the Picstart Plus is selected and that the correct com port is selected. Make certain that everything is plugged in.
If the enable succeeds, the programmer dialog box will appear. Verify that the device is PIC12C509, the Oscillator is Internal RC, the Watchdog Timer is ON, Code Protect is Off, and Master Clear is Internal. These should be the values as loaded; if you have to change them, it is likely that the processor setup described above is incorrect.
Put in a new device. Be careful to put it so that pin 1 is all of the way to the top of the socket.
Click the Blank button in the dialog box. The program should reply with a Device Is Blank message box.
Click the Program button in the dialog box. A new dialog box will appear; do not touch it. Programming should proceed to a successful conclusion. At this point, it comes up with a message saying that the calibration location is already programmed, and was not programmed at this time. This is a good result; it means that the factory calibration of the 4 MHz oscillator on the chip is present.
Unload the chip from the programmer, and put it on the speed controller board.

I do not know how other programmers for this processor work. However, a requirement is that they not overwrite location H'3FF' in instruction memory; this location is programmed at the factory to make the built in clock oscillator run at the proper frequency. The hex file does not specify a value for this address, so that programmers which program only what is in the hex file will work fine. (Note: the hex file addresses are double the instruction memory addresses; two bytes are present for each instruction.)

May be copied as desired and modified as needed so long as this copyright notice is preserved.

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