Dear Friends Hi!!!!!!!
This is my first post and I would like to say a big HELLO to everyone,and keep doing this wonderfull job.....I have a problem concerning the circuit below....
RGB Fading Using 3 LEDs and PWM
I cant programm correct the chip.....I use ic-prog and plms ozi pic'er programmer...the MPASMWIN assembles the file correct but when i burn it,it fails in the verify mode...The writer says some modifications to be done but I am new to microcontrollers world and i dont have the expierience to correct it.....If anyone can help me i would appriciate it a lot!!!!!!Also i couldn't find his e-mail address to ask him......
The Author says.......
*The code assumes that the OSCAL Oscillator Calibration value is present in program memory at address 0x3FF. This is a RETLW instruction that returns a value factory set by Microchip at the time of manufacture to calibrate the internal 4Mhz oscillator accurately. Because this instruction is in normal program memory it can be erased. If this happens for whatever reason, when the code makes a call to 0x3FF there is no RETLW instruction present so the application will not run correctly or just hang.
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*The programmer software I use reads the calibration value out of the device to be programmed and then merges it with the .HEX code before programming. From enquires I've had, not all programmers do this and people have erased the calibration setting without realising it and of course the code then doesn't work.
*If this happens you need to rewrite memory location 0x3FF with a RETLW instruction. The assembler instructions to do this are:
This won't calibrate the internal oscillator to exactly 4Mhz (unless the calibration value was 0x7F), but it won't be far off and most importantly it ensures that if a program attempts to read the calibration value there is something there for it to return.
What should i do?
Thanks a lot Panagiotis