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I am using a Rix51 board with 8xc251TB and SAB82526 HDLC controller. I want to memory map the HDLC registers so that I can easily read-write to them in C code. For example to write to a FIFO register addressable at 0x40 location internally in SAB82526 I do the following : #define FIFO *(volatile unsigned char far *)(0x01FD40) FIFO = 0x01; Is the above incorrect in any way because I am unable to write in the above manner . Though there are no errors/warnings during building but while running on the simulator (uvision2) , I dont get the expected values at expected addresses. Can anyone help? Thanks Puneet
Try this: volatile unsigned char near HWData _at_ 0x000800; This is what we use in our 251 application. You may need to change the modifiers (unsigned char, near) to match your application, but the key part is the _at_. This defines a fixed address location at the specified address.
I have tried this. (i have to use xdata as mine is an external memory map). Now though it correctly assigns the variable values but still the correct values are not visible in the memory. (memory window of the uvision debugger) Does the memory window not show externally mapped i/os?
Does the memory window not show externally mapped i/os? How could it? Maybe I don't understand but unless you have an in-circuit emulator hooked up to real hardware, you're not going to see your real mem. mapped values. - Mark
i am yet not running the application on actual hardware but just on the simulator environment provided by uvision. So i guess the memory window should show me the details. Also if you know of any monitor program for downloading and running (with breakpoints,etc) the 251 applications on a Rix51 board, please let me know. Thanks
Maybe an application for the newly-documented rwatch and wwatch Predefined Debug Functions? See the post, "rwatch, wwatch in uVision v2.07 & later" http://www.keil.com/forum/msgpage.asp?MsgID=1025 Basically, they let a Signal Function wait until a specific address is read/written. So perhaps you could use them to wait for an access to the address of your mem-mapped peripheral, and then do whatever's required when the access occurs?