Robot Beacon with PIC12C508A
Posted on Feb 20, 2013 8712
Under: Robotic Circuits
We hold the `first rights` to the presentation of this approach and the best part is: `It's FREE!` The PIC12C508A is one of the most amazing devices but because it does not come in a low-cost re-programmable form, it has never been presented in a `designers article.` It is a one-time programmable device (OTP) and once it is programmed, it cannot be re-programmed. To develop with this chip is not an economical decision as it may take 30 to 100 modifications before you are completely happy with the operation of the software. That's 99 wasted chips! The only way to carry out experimentation is with the EPROM version (window version). These carry the part number PIC12C508A-JW and are about 10 times the cost of a normal PIC12C508A.
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To remove the program, they must be erased under an ultra-violet lamp for about 20 minutes. When you are in the process of developing, this time-delay is very annoying and it usually takes about 10 units to keep the development process active. Adding up the costs, makes this process slow, cumbersome and costly. We have got around this problem by using a PIC16F84 to hold the development program and when you are completely satisfied with the operation, the EXACT SAME program is burnt into a PIC12C508A. All you have to do is select "12C508A" in the chip list on MPASM and the program will be assembled with a .hex file to suit a 508A. Click on ICProg, select 508A as the chip to be programmed, insert a 508A into the Multi Chip Programmer and the program will be burnt into the 8 pin chip. The .hex files for the two chips are entirely different as the "core" of each is different, but that does not involve us. The programming instructions are the "same" and the circuit-operation is the same. The secret to this approach is to use only the instructions and files that are common to both chips. Fortunately nearly all the instructions for the 16F84 can be used by the 508A and nearly all the files are common. The table above shows the similarities etc. The PIC12C508A chip is theoretically a One Time Programmable device, but it can be re-burnt, providing a number of points are remembered. Any location can be re-burnt "down."...