MPASM 18F4550 getting started

[BrianT]

Hi All,

Can someone please get me started by posting the first one or two pages of a working program using MCSP 3.0.0.0 with PBP 2.47 and MPASM together with a PIC18F4550. I am having great trouble getting the syntax right and I keep getting crazy errors when converting a satisfactorily working 16F877A program over to MPASM and the 18F4550.

I need to see how to get the first few define, include and device statements to work. Yes I have the MPASM manual, all 270 pages, and I am reading up on this as best I can, but it can be all a bit subtle as to where to use __ or _ and what goes in the first column or later.

I have installed MPASM in c:\mpasm and PBP in c:\pbp and my code in c:\testcode to get the path lengths to a minimum but I still get errors such as processor not defined, syntax errors and illegal declarations.

Any help gratefully received.

Cheers
Brian

[Darrel Taylor]

>> working program using ... PBP 2.47 and MPASM together with a PIC18F4550

This might fit the bill.

USBDemo, something to learn USB a little bit
http://www.picbasic.co.uk/forum/showthread.php?t=5418
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[BrianT]

Thanks Darrel, a fair bit to digest in the threads you pointed me to. I will unzip (the files that is) and go through them tonight.

Cheers
Brian

[BrianT]

Hello Darrel namesake.

I had a hard drive crash last week and had to replace the disk. I thought I had properly backed it up BUT a quick check this morning showed my MCS+ had reverted to 2.2.x.x. I reloaded MCS+ 3.0.0.0 and now I am nearly getting the 18F4550 to work. Not quite there though.

Sorry to appear ungrateful but the USB example does not do it for me.
a/ Surely we can stay within PBP and not need an ASM ..... ENDASM block at the start to configure the processor? No big deal, but a surprise to me.

b/ The USB example does not properly compile for me. I have unzipped all the files in the USB example and placed them in a directory c:\testcode. I have loaded the USBDemo.pbp into MCS+ (3.0.0.0) with PBP (2.47) and I have selected the 18F4550 in the MCS+ processor selection drop down. I have selected MPASM (freshly downloaded last week) as the assembler.

MPASM threw up many errors so I changed _FCMEN_OFF_1H to _FCMEM_OFF_1H which brought the errors down to ten lines of errors, all of the form:-

Error [118] c:\pbp\USBdemo.asm 128: Overwriting previous address contents (0000)
Error [118] c:\pbp\USBdemo.asm 134: Overwriting previous address contents (0000)

During the assembly, MPASM buts up a green box that flashes past then a red box and then MCS+ gives the error lines above. Page 159 of the MPASM User's Guide was not helpful.

What is the signifigance of the 'overwriting' errors? Is this a bug in the supplied example?

Cheers
Brian

[Darrel Taylor]

Common problem.

http://www.picbasic.co.uk/forum/show...75&postcount=5
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