[En-Nut-Discussion] accesing registers

[Harald Kipp]

Neither, the ARM nor the AVR platform provide a specific I/O bus.
The AVR has a special range of I/O registers with enhanced
access mode (like bit instructions). But all ports are memory
mapped per se.

Nut/OS uses in/out macros when accessing I/O registers just to
maintain portability and simulation. But of course memory
pointers to register addresses will work too.

Harald


At 12:51 09.03.2006 +0100, you wrote:
>Hi again:
>
>I'm starting with Ethernut 3 and have a doubt about accesing ports. In
>the document "memory.html", where is described the memory map and ports,
>says that the CPLD registers are at 0x21000000 - 0x210FFFFF, which seems
>to mean that they are memory-mapped. Do I must access them with memory
>pointers, or can I use OUTR, like:
>
>     outr(NPL_RSCR, data);
>
>to access the NPL rs232 register? It's not much clear.
>
>Thanks.