Upgrading FROM PIC18F452 to bigger PIC?

jseidmann · Joined: 04 Nov 2004 Posts: 67

Hi everyone,

I've looked over the microchip catalog, but I couldnt find anything so i'm asking you guys. I'm using the PIC18F452 in a commercial product and I am running out of program memory. Is there any easy (or relatively easy) way to upgrade to another chip that has the same pinout, but more memory? Has anyone here done that from the 18F452?

thanks,

Jseidmann

pirev · Joined: 19 Mar 2005 Posts: 13 Location: Bulgaria

Try with PIC18F4525(48kB) or PIC18F4620(64kB).

Ttelmah · Guest

Yes.
The direct 'upgrade' for the 452, is the 4520, which has the same amount of memory, adds the comparators, and the 'NanoWatt' features. It is 99% compatible (a couple of tweaks to the configuration code, and disabling the comparators etc.). This is the chip that should be being used for 'new products' anyway, since the 452,is likely to be phased out eventually. The 4620, is then the step up from this.
Generally, they are very compatible, but there are quite a few erratas for some versions (which adds a few problems).
The features that 'differ', are the addition of the comparators, the USART, changes to a EUSART (which the compiler now handles, but caused some problems initially), more EEPROM (1KB), more prescalers for the watchdog, and more features on the CCP (fortunately, reverse compatible, if these are not enabled).
Generally, it should be possible to transfer code with only a few minutes work.

Best Wishes