Motorola DSP56301 - Manual (Page 112)

Mapping the Control Registers
5 -2 DSP56301 User’s Manual
5.2 Mapping the Control Registers
The I/O peripherals are controlled through registers mapped to the top 128 words of X-data
memory ($FFFF80–$FFFFFF). Referred to as the internal I/O space, the control registers are
accessed by move (MOVE, MOVEP) instructions and bit-oriented instructions (BCHG,
BCLR, BSET, BTST, BRCLR, BRSET, BSCLR, BSSET, JCLR, JSET, JSCLR, AND
JSSET). The contents of the internal X I/O memory space are listed in Appendix B,
Programming Reference, Table B-2.
Figure 5-1. Memory Mapping of Peripherals Control Registers
5.3 Data Transfer Methods
Peripheral I/O on the DSP56301 can be accomplished in three ways:
n Polling
n Interrupts
n DMA
5.3.1 Polling
Polling is the easiest method for data transfers. When polling is chosen, the DSP56300 core
continuously checks a specified register flag waiting for an event to happen. One example
would be setting an overflow flag in one of the Timers. Once the event occurs, the DSP56301
is free to continue with its next task. However, while it is waiting for the event to occur, the
X Data Memory
Internal I/O
External
Internal
Reserved
External
Internal
X Data RAM
2K (default)
$FFFFFF
$FFFF80
$FFF000
$FF0000
$0007FF
$000000
Peripheral Control Registers
Memory Space