I've reached the limit of progam memory in a couple of 16F877 projects.
The code is all written in C using the CCS compiler.
I'm considering using the 18F252 as a drop-in replacement and buying the PCH compiler to recompile the C code.
Is this chip a good choice for the migration?
Where can I find info re: tricks & traps to look out for when migrating from 16F to 18F chips and PCM to PCH.
Am I just being too paranoid and probably won't encounter any major headaches?
Thanks,
Patrick
Chas Guest
Posted: Wed Mar 10, 2004 8:56 am
I just did the same thing on a recent project and had the same paranoia that you do. I was completely wrong. The transistion was fairly straight forward. The changes that I needed to be aware of follow:
LVP pin is changed to RB5 on the 18F parts.
Change any direct register address assignments.
Change any direct pin assignments
Change #fuse parameters
Be aware that memory addressing is in 8 bit bytes with instructions on the even word boundaries
Beyond the above I had fairly smooth sailing.
Let us know how it works out.
Ttelmah Guest
Posted: Wed Mar 10, 2004 10:49 am
Chas wrote:
I just did the same thing on a recent project and had the same paranoia that you do. I was completely wrong. The transistion was fairly straight forward. The changes that I needed to be aware of follow:
LVP pin is changed to RB5 on the 18F parts.
Change any direct register address assignments.
Change any direct pin assignments
Change #fuse parameters
Be aware that memory addressing is in 8 bit bytes with instructions on the even word boundaries
Beyond the above I had fairly smooth sailing.
Let us know how it works out.
Add that you have to modify your thinking if you are using the EEPROM. On the 18 parts, the data you have to store for this is mapped as if this is 16bits wide.
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