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ADSP-2191 Host Port booting
Software boot loader

Version:   1.02
Date:      06.11.2003
Author:    Michael Kuegler
Company:   Analog Devices, Inc.

Target:    ADSP-2191 EZ-KIT Lite 2.1
Platform:  VisualDSP++ 3.0 for 21xx

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This directory contains the software boot loader described in application note
"ADSP-2191 Host Port booting".
The program initialises the Host DSP (External Port, GPIO Flags, Interrupts),
the PLD (only reset) and the Target DSP (Host Port). It then calls a function
that transfers the content of the loader file to the Target DSP via the Host
Port.
A simple handshake method is used to make sure that the boot process was
successful:
  - Boot loader clears some memory locations in Target memory (handshake
    locations)
  - Boot loader starts program execution on Target
  - Boot loader waits for program execution to start on Target
  - Program running on Target writes certain values in handshake locations
  - Boot loader verifies content of handshake locations

  
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Files contained in this directory:

Main.c                 Main program, calling initialisation and boot loader
Initialisation.c       Initialisation functions for Host and PLD
ISRs.c                 Interrupt Service Routines for project
Loader File Access.c   Functions for accessing Host loader file
Host Port Access.c     Functions for low level access to Host Port via PLD
Boot Loader.c          Software boot loader


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File hierarchy:

Main
  |
  +--- Initialisation
  |      |
  |      +--- Host Port Access
  |
  +--- Boot Loader
         |
         +--- Loader File Access
         |
         +--- Host Port Access


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Restrictions:

1. The maximum size of the loader file is 64kB.
   This is due to the fact that the loader file, which is stored in the Host
   EZ-KIT Flash, is accessed via the External Port. For these accesses, page
   crossing is not implemented.
2. No external memory is supported for the loader file.

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