Programming Embedded Systems in C and C++

Learn How to Communicate 47

peripherals. The chips that control the parallel port and debugger port reside out-

side of the processor. These ports are used to communicate with the printer and a

host-based debugger, respectively.

The I/O map is also useful when creating the header file for your board. Each

region of the I/O space maps directly to a constant, called the base address. The

translation of the above I/O map into a set of constants can be found in the fol-

lowing listing:

/**********************************************************************

*

* I/O Map

*

* Base Address Description

* --------------- ----------------------------------------

* 0000h Unused

* FC00h SourceVIEW Debugger Port (SVIEW)

* FD00h Parallel I/O Port (PIO)

* FE00h Unused

* FF00h Peripheral Control Block (PCB)

*

**********************************************************************/

#define SVIEW_BASE 0xFC00

#define PIO_BASE 0xFD00

#define PCB_BASE 0xFF00

Learn How to Communicate

Now that you know the names and addresses of the memory and peripherals

attached to the processor, it is time to learn how to communicate with the latter.

Figure 5-3. I/O map for the Arcom board

Peripheral

Control Block

FFFFh

FF00h

Parallel Port

FE00h

Unused

Debugger Port

Unused

FD00h

FC00h

0000h

48 Chapter 5: Getting to Know the Hardware

There are