On Sat, 3 Aug 2002 07:19:45 -0400 Byron A Jeff writes: > On Sat, Aug 03, 2002 at 04:36:21PM +1200, Jinx wrote: > > Tony, why do some of your instructions include the ,A ? > > It's the 18XXXX "access bank". It's a special memory designation > that consists > of the special function registers + 128 bytes of handily accessible > general > purpose RAM in bank 0. It's special because you can access it > directly without > having to switch/setup the bank select register. It's described in > secton 4.10 > of the 18FXXX datasheet. > But, the Microchip assembler automatically decides whether to use the access bank or not, so you need not include the last parameter in your source code. If the address is in the access bank, access bank addressing is used. If not, the assembler tells the processor to use the BSR to get to the memory location. That can be kind of a pain, since you may have to keep changing bsr. You can (as in all PICs) use an FSR to access all of RAM without messing with banks. Also, on the 18 series is the movff instruction. It lets you access all of RAM without use of the bsr. Also, since the wreg has a RAM address, you can do stuff like movff something, wreg. Harold FCC Rules Online at http://hallikainen.com/FccRules Lighting control for theatre and television at http://www.dovesystems.com Reach broadcasters, engineers, manufacturers, compliance labs, and attorneys. Advertise at http://www.hallikainen.com/FccRules/ . ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/web/. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads