Post by thread:Migrating From 16C73A to 16F873

Hi Everyone, I have attempted (unsuccessfully so far) to migraite some code I've tested on a 20 MHZ 16C73A-JW to a 20 MHZ 16F873 flash pic. An engineer at Microchip told me that they are pin for pin compatible and are functionally very similar, so it should be a no-brainer. --Turns out it's requiring brains after all (I am not surprised). I have a standard Hitachi 4 x 20 LCD which does not seem to initialize and I get no characters displayed. However, an interrupt routine which worked on the 16C73A seems to work ok, so it must be a timing issue of sort. Does anyone out there know of any migration issues when porting code written for a 16C73A to a 16F873? I have checked Microchip's web-site and cannot find any such migration document although you would think one should exist. Any help would definitely be appreciated. --Bill

Bill wrote: > > Hi Everyone, > > I have attempted (unsuccessfully so far) to migraite some code I've > tested on a 20 MHZ 16C73A-JW to a 20 MHZ 16F873 flash pic. An engineer at > Microchip > told me that they are pin for pin compatible and are functionally very > similar, so it should be a no-brainer. --Turns out it's requiring brains > after all (I am not surprised). I have a standard Hitachi 4 x 20 LCD which > does not seem to initialize and I get no characters displayed. However, an > interrupt routine which worked on the 16C73A seems to work ok, so it must > be a timing issue of sort. Does anyone out there know of any migration > issues when porting code written for a 16C73A to a 16F873? I have checked > Microchip's web-site and cannot find any such migration document although > you would think one should exist. Any help would definitely be appreciated. > > --Bill The only differences are... 2 extra interrupts, flash ROM, 10 bit A2D, 128/256 bytes of EEPROM. Check the RAM maps too for special function register addresses. Make sure the LVP bit is not enabled when programming, or the chip may go into low voltage programming mode if RB3 is connected to an external device. -- Best regards Tony http://www.picnpoke.com spam_OUTsalesTakeThisOuTpicnpoke.com

Hi, you could have a problem using A/D as 16C73A has 8 bit resolution, and 16F873 has 10 bit. If you use A/D, it can be a (not very big) concern. Regards, Imre On Mon, 21 Feb 2000, Bill wrote: {Quote hidden}> Hi Everyone, > > > I have attempted (unsuccessfully so far) to migraite some code I've > tested on a 20 MHZ 16C73A-JW to a 20 MHZ 16F873 flash pic. An engineer at > Microchip > told me that they are pin for pin compatible and are functionally very > similar, so it should be a no-brainer. --Turns out it's requiring brains > after all (I am not surprised). I have a standard Hitachi 4 x 20 LCD which > does not seem to initialize and I get no characters displayed. However, an > interrupt routine which worked on the 16C73A seems to work ok, so it must > be a timing issue of sort. Does anyone out there know of any migration > issues when porting code written for a 16C73A to a 16F873? I have checked > Microchip's web-site and cannot find any such migration document although > you would think one should exist. Any help would definitely be appreciated. > > > --Bill > >

Hey Tony, Re: 16C73A vs. 16F873 {Quote hidden}>The only differences are... > >2 extra interrupts, flash ROM, 10 bit A2D, 128/256 bytes of EEPROM. > >Check the RAM maps too for special function register addresses. > >Make sure the LVP bit is not enabled when programming, or the chip may >go into low voltage programming mode if RB3 is connected to an external >device. Many thanks! The LVP bit was in fact on and I am using RB3. Turned LVP off and indeed all is well. Excellent. One of the differences you cite between the chips is 128/256 of EEPROM. Do you mean that there is a flavour which has 256? (I believe the one I have has 128). --best regards, Bill

Hi Imre, Thanks for your response. Turns out it must have ben the LVP bit being set to on during programming. Your point concerning 8 vs. 10 A/D conversion, is in fact a valid consideration for my application and I am aware of this. I now have everything working. --best regards, Dr. Bill Showkowy At 11:15 AM 2/22/00 +0100, you wrote: {Quote hidden}>Hi, > >you could have a problem using A/D as 16C73A has 8 bit resolution, and >16F873 has 10 bit. If you use A/D, it can be a (not very big) concern. > >Regards, >Imre > > >On Mon, 21 Feb 2000, Bill wrote: > >> Hi Everyone, >> >> >> I have attempted (unsuccessfully so far) to migraite some code I've >> tested on a 20 MHZ 16C73A-JW to a 20 MHZ 16F873 flash pic. An engineer at >> Microchip >> told me that they are pin for pin compatible and are functionally very >> similar, so it should be a no-brainer. --Turns out it's requiring brains >> after all (I am not surprised). I have a standard Hitachi 4 x 20 LCD which >> does not seem to initialize and I get no characters displayed. However, an >> interrupt routine which worked on the 16C73A seems to work ok, so it must >> be a timing issue of sort. Does anyone out there know of any migration >> issues when porting code written for a 16C73A to a 16F873? I have checked >> Microchip's web-site and cannot find any such migration document although >> you would think one should exist. Any help would definitely be appreciated. >> >> >> --Bill >> >> >