Is it true that the PIC16C558 is nearing the end of its life ? If so is the 16C622 the best alternative ? Steve -----Original Message----- From: Philippe To: PICLIST@MITVMA.MIT.EDU Date: Monday, April 12, 1999 8:02 AM Subject: Re: Pic 16C554 and Interrupts >At 08:27 09/04/99 -0400, you wrote: >>Ran across a problem with interrupts in the Pic 16C554. >> >>There is only data ram on page 0 and one wants to access values on ram page >>1 such as TRISB, etc. The problem is that the published interrupt context >>save routines (and the ones we have been using for 1000 years) presume that >>the W register can be saved on the bank which is currently in the STATUS >>register. If page 1 of ram is current then the W register gets restored with >>the value which has been "stored" in phantom ram -- which is a 0. Not real >>funny when one is trying to set an input value on a TRIS register! >> >>Anyone have a workaround context save routine? (Or a directive telling me >>not to have interrupts on when I am in page 1 of the 554?) > >Nothing to do with 554,556 and 558, the only way is simply to avoid interrupt >when you are in PAGE 1, or if you are only trying to configure TRIS register, >use TRIS instruction instead of page switching. >With 558 it may be possible to save page, as there is RAM from $A0 to $BF. >Remember 558 is going to end of life and it is now better to use PIC16C622A >for mass-production. > >Regards, > Philippe. > > +----------------------------------------------------+ > | Virtual Micro Design | > | | > | Have you tryed the fastest PIC Simulator ? | > | UMPS at: http://www.vmdesign.com | > | | > | Phone: ++33 559.438.458 Fax: ++33 559.438.401 | > | | > | E-Mail: p.techer@vmdesign.com | > | URL: http://www.vmdesign.com | > +----------------------------------------------------+ >