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Сигнальный МП Motorola DSP56002.pdf
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Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

HOST INTERFACE (HI)

MODES

7

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INIT

HM1

HM0

HF1

HF0

0

TREQ

RREQ

 

INTERRUPT CONTROL REGISTER (ICR)

$0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(READ/WRITE)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RESET CONDITION

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

0

Interrupt Mode (DMA Off)

 

 

 

 

 

 

01 24 Bit DMA Mode

10 16 Bit DMA Mode

1

1

8 Bit DMA Mode

INTERRUPT MODE (DMA OFF)

 

 

 

 

 

TREQ

RREQ

 

HREQ PIN

 

 

 

 

 

 

0

0

No Interrupts (Polling)

01 RXDF Request (Interrupt)

10 XDE Request (Interrupt)

1

1

XDF and TXDE Request (Interrupts)

 

 

 

DMA MODE

 

 

 

 

 

 

 

 

TREQ

RREQ

 

 

PIN

 

HREQ

 

 

 

 

 

 

 

 

 

 

0

0

No DMA

01 DSP to Host Request (RX)

10 Host to DSP Request (TX)

1

1

Undefined (Illegal)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INTERRUPTSTATUS

 

 

$2

 

 

HREQ

DMA

0

HF3

HF2

TRDY

TXDE

RXDF

 

REGISTER(ISR)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(READONLY)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

HOST STATUS

X:$FFE9

 

DMA

0

0

HF1

HF0

HCP

HTDE

HRDF

 

REGISTER (HSR)

 

 

 

 

 

 

 

 

 

 

 

(READ ONLY)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 5-38 Host Bits with TREQ and RREQ

matically loads the DMA address counter from the HM1 and HM0 bits in the DMA host to DSP mode. This DMA address is used with the HI to place the received byte in the correct register (TXH, TXM, or TXL).

Figure 5-37 shows the differences between 24-, 16-, and 8-bit DMA data transfers. The interrupt rate is three times faster for 8-bit data transfers than for 24-bit transfers. TXL is always loaded last.

5.3.6.3.2Host to DSP DMA Procedure

The following procedure outlines the typical steps that the host processor must take to setup and terminate a host-to-DSP DMA transfer (see Figure 5-39).

5 - 58 PORT B MOTOROLA

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

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