Motorola DSP56011 User Manual

Digital audio transmitter

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Freescale Semiconductor, Inc.
SECTION 8
DIGITAL AUDIO TRANSMITTER
MOTOROLA
DSP56011 User's Manual
8-1
For More Information On This Product,
Go to: www.freescale.com
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Summary of Contents for Motorola DSP56011

  • Page 1 Freescale Semiconductor, Inc. SECTION 8 DIGITAL AUDIO TRANSMITTER MOTOROLA DSP56011 User’s Manual For More Information On This Product, Go to: www.freescale.com...
  • Page 2: Table Of Contents

    DAX INTERNAL ARCHITECTURE ....8-6 DAX PROGRAMMING CONSIDERATIONS ... . 8-14 DSP56011 User’s Manual MOTOROLA For More Information On This Product, Go to: www.freescale.com...
  • Page 3: Overview

    “polling” technique. A block diagram of the DAX is shown in Figure 8-1 . Note: The shaded registers in Figure 8-1 are directly accessible by DSP instructions. MOTOROLA DSP56011 User’s Manual For More Information On This Product, Go to: www.freescale.com...
  • Page 4: Dax Signals

    Note: If the DAX is not used, connect the ACI pin to ground through an external pull-down resistor to ensure a stable logic level at the input. DSP56011 User’s Manual MOTOROLA For More Information On This Product,...
  • Page 5: Dax Functional Overview

    ADO pin at the last two time slots. This is the end of the first (Channel A) sub-frame transmission. MOTOROLA DSP56011 User’s Manual For More Information On This Product, Go to: www.freescale.com...
  • Page 6: Dax Programming Model

    DAX INTERNAL ARCHITECTURE Hardware components shown in Figure 8-1 on page 8-4 are described in the following sub-sections. The DAX programming model is illustrated in Figure 8-2 . DSP56011 User’s Manual MOTOROLA For More Information On This Product, Go to: www.freescale.com...
  • Page 7 This double buffering mechanism provides more cycles to write the next audio data to XADRA and XADRB. This register is not directly accessible by DSP instructions. MOTOROLA DSP56011 User’s Manual For More Information On This Product, Go to: www.freescale.com...
  • Page 8 DAX is done at the next frame boundary after finishing the current frame transmission. Note: This bit is cleared by software reset and hardware reset. DSP56011 User’s Manual MOTOROLA For More Information On This Product, Go to: www.freescale.com...
  • Page 9 The value of the XVB bit is transmitted as the twenty-ninth bit (Bit 28) of the Channel B sub-frame in the next frame. Note: This bit is not affected by any of the DAX reset states. MOTOROLA DSP56011 User’s Manual For More Information On This Product, Go to: www.freescale.com...
  • Page 10 However, it causes a change in the interrupt vector that is sent to DSP core, if an interrupt is generated. This allows programmers to write an exception handling routine for this special case. 8-10 DSP56011 User’s Manual MOTOROLA For More Information On This Product, Go to: www.freescale.com...
  • Page 11 XEN bit, when XSTP = 0), or it is cleared at the next frame boundary (if XSTP = 1). Note: Software reset, hardware reset, and the Stop state clear XTIP immediately. MOTOROLA DSP56011 User’s Manual 8-11 For More Information On This Product,...
  • Page 12 Table 8-4. The preamble bits are already in the biphase mark format. Table 8-4 Preamble Bit Patterns Preamble Bit Pattern Channel 00011101 00011011 00010111 A (first in block) 8-12 DSP56011 User’s Manual MOTOROLA For More Information On This Product, Go to: www.freescale.com...
  • Page 13 Figure 8-5 shows how each clock is divided to generate the biphase and bit shift clocks. DSP Core Clock (1024 ACI Pin Biphase {256,384,512} Clock (128 Bit Shift (XCS1 or XCS0) Clock XCS1 XCS0 AA0610 Figure 8-5 Clock Multiplexer Diagram MOTOROLA DSP56011 User’s Manual 8-13 For More Information On This Product, Go to: www.freescale.com...
  • Page 14: Dax Programming Considerations

    Within the routine, the next audio data can be stored in the XADRA/XADRB registers, and the next non-audio data can also be stored in the XCTR. 8-14 DSP56011 User’s Manual MOTOROLA For More Information On This Product, Go to: www.freescale.com...
  • Page 15 DAX control bits are affected. It is recommended that the DAX be disabled, by clearing the XEN bit in the XCTR, before the DSP enters the Stop state. MOTOROLA DSP56011 User’s Manual 8-15 For More Information On This Product, Go to: www.freescale.com...
  • Page 16 Freescale Semiconductor, Inc. Digital Audio Transmitter DAX Programming Considerations 8-16 DSP56011 User’s Manual MOTOROLA For More Information On This Product, Go to: www.freescale.com...