dsp56167 Freescale Semiconductor, Inc, dsp56167 Datasheet - Page 91

• Manufacturer Part Number: dsp56167
• Description: Advance Information 16-bit Digital Signal Processor
• Manufacturer: Freescale Semiconductor, Inc

SPECIAL DESIGN CONSIDERATIONS FOR CONVERSIONS FROM
DSP56166 TO DSP56167
New Feature Descriptions
MOTOROLA
PROGRAMMABLE ABSOLUTE SHORT ADDRESSING MODE (PASAM)
There are several areas to consider when converting a design using a DSP56166 to a
design using the DSP56167. Although the DSP56167 is software and pin compatible
with the DSP56166, some external component changes are required. Not only have
additional features been added in the DSP56167, but there are also changes to existing
circuitry that affect DSP operation and circuit design. In addition, several errata in the
DSP56166 have been fixed in the DSP56167. The following sections provide detailed
information about these design changes.
Note: All references to RSSI are now listed as SSI.
New features added to the DSP56167 include:
The following sections provide a detailed description of these new features and
provide guidelines for use in applications.
Previously on the DSP56166, the absolute short addressing mode allowed the user to
access the first 32 locations, from X:$0000 throughX:$001F, of the data memory space
using a one word move or bitfield instruction. This feature has been enhanced to
allow the user to access any 32 locations within the data memory space, from X:$0000
to X:$FFFF. The block of 32 locations or page of the data memory space is selected by
programming the upper 11 bits of the Address ALU Programmable Absolute Short
Addressing Mode register (PASAM —X:$FFCA), wait one instruction cycle due to
the pipeline delay, and then access the new page using the same absolute short
addressing mode instruction. Figure 4-8 on page 4-16 shows the PASAM
architecture.
• Programmable absolute short addressing mode (PASAM)
• Peripheral Address Generation Unit (PAGU)
• Independent external chip enable signals BR and PEREN
• Port A BG pull-down under software control
• Port A and OnCE port DR signal line keepers with reset
• External program memory access disable
Special Design Considerations for Conversions from DSP56166 to DSP56167
DSP56167/D, Rev. 1
Design Considerations
4-15