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Сигнальный МП Motorola DSP56002.pdf
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Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

HOST INTERFACE (HI)

 

 

 

 

 

 

 

 

 

MASK

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

0

0

HF3

HF2

HCIE

HTIE

HRIE

 

 

 

 

 

 

HCR

X:$FFE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DSP CPU INTERRUPTS

RECIEVE DATA FULL

P:$0020

TRANSMIT DATA EMPTY

P:$0022

HOST COMMAND

P:(2xHV $0000 - $007E)

RESET HV = $0012 in CVR

 

 

7

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DMA

0

0

HF1

HF2

HCP

HTDE

HRDF

 

 

X:$FFE

 

 

HCR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

STATUS

Figure 5-11 HSR–HCR Operation

side are discussed in Section 5.3.6.5 Host Port Usage Considerations – Host Side.

DMA, HF1, HF0, HCP, HTDE, and HRDF status bits are set or cleared by the host processor side of the interface. These bits are individually synchronized to the DSP clock.

The only system problem with reading status occurs if HF1 and HF0 are encoded as a pair because each of their four combinations (00, 01, 10, and 11) has significance. There is a small possibility that the DSP will read the status bits during the transition and receive

“01” or “10” instead of “11”. The solution to this potential problem is to read the bits twice for consensus (See Section 5.3.6.5 Host Port Usage Considerations – Host Side for additional information).

5.3.3Host Interface – Host Processor Viewpoint

The HI appears to the host processor as eight words of byte-wide static memory. The host may access the HI asynchronously by using polling techniques or interrupt-based techniques. Separate transmit and receive data registers are double buffered to allow the DSP CPU and host processor to transfer data efficiently at high speed. The HI contains a rudimentary DMA controller, which makes generating addresses (HA0–HA2) for the TX/RX

MOTOROLA PORT B 5 - 19

For More Information On This Product, Go to: www.freescale.com

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