Motorola DSP56012 User Manual

4-42

DSP56012 User’s Manual

MOTOROLA

Parallel Host Interface

Host Interface (HI)

4.4.8

Host Interface Application Examples

The following paragraphs describe examples of initializing the HI, transferring data
with the HI, bootstrapping via the HI, and performing DMA transfers through the
HI.

4.4.8.1

HI Initialization

Initializing the HI takes two steps (see

Figure 4-18

). The first step is to initialize the

DSP side of the HI, which requires that the options for interrupts and flags be
selected and then the HI be selected (see

Figure 4-19

on page 4-43). The second step

is for the host processor to clear the HC bit by writing the CVR, select the data
transfer method-polling, interrupts, or DMA (see

Figure 4-25

on page 4-48 and

Figure 4-26

on page 4-50), and write the IVR (in the case of an MC680XX family host

processor).

Figure 4-19

on page 4-43 through

Figure 4-22

on page 4-46 provide a

general description of how to initialize the HI. Later paragraphs in this section
provide more detailed descriptions of specific examples. These subsections include
some code fragments illustrating how to initialize and transfer data using the HI.

Figure 4-18 HI Initialization Flowchart

Step 1

The DSP CPU initializes the DSP side
of the HI by writing:
1) HCR at X:$FFE8 and
2) PBC at X:$FFE0

STEP 2

The Host Processor initializes the host
side of the HI by writing:
1) ICR at $0 and/or
2) CVR at $1 and/or
3) IVR at $3

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