![]() These can be accessed without bank-switching. It is possible to declare up to 128 bytes' worth of global and static variables to be 'near'. The linker does overlay variables which are never live simultaneously, but it assumes any call to a function pointer with a particular signature can call any function whose address is taken and which has that signature. Arrays of bytes, as well as individual bytes, go in a "big" psect where every byte is assumed to possibly reside in a different page.Īll automatic variables and parameters throughout the program must fit in a 256-byte page (they are allocated statically at link time). Global and static ints and structs, and arrays thereof, whose size ranges from 2-255 bytes will each be allocated into psects on a per-module basis each module's psect must fit in a 256-byte page. Direct access to a variable requires that the proper bank be selected changing banks takes one instruction. Brief background: the chip has 16 256-byte banks of variables (*not all 256 bytes are available in all banks) and one bank pointer. While I appreciate not having to hand-place all variables into banks, the rules used by HiTech's compiler are annoying, bizarre, and goofy. I've generally liked their PIC16 compiler, but find their PIC18 compiler rather frustrating. I've not used the Microchip compiler, but have been using HiTech's products for years. It also seemed to take a verrrryyy long to compile but it could have been b/c of the program complexity. But, my project exceeded the auto param block requirements and was unable to use it. they aren't fixing bugs anymore which is a real shame. but from my experience with HiTech support. it seems that they are no longer supporting HiTide. However, since Microchip has purchased HiTech. I am an avid eclipse fan and so I really liked HiTech's HiTide for this reason. You cannot allocate variables which are larger then 256 bytes without editing a linker script.Īn excellent comparison which goes way more in depth can be found here: īesides from the compiler you also need to take into consideration the IDE.In order to have const string be allocated to Program space (instead of ram) you have to use the rom keyword.You have to specify which ram bank to allocate variables to.With C18 you have add all kinds of compiler specific keywords and your forced to manage memory much more. ![]() #Free c compiler for pic18 code#HiTech's solution is much closer to ANSI C (hence code is much more portable). ![]() I think most people that decide to go with Microchip C18 compiler only because they see it when they go to the microchip website and are already familiar with MpLab from doing assembly (which is a terrible IDE IMHO). I did extensive research on the Hitech PICC18 compiler and the Microchip C18 compiler a few years ago.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |