VisualDSP++ 4.5 Loader and Utilities Manual - Analog Devices

PROM Boot Mode
Introduction
After reset, the processor starts reading data from a parallel or serial
PROM device. The PROM stores a formatted boot stream rather than raw
instruction code. Beside application data, the boot stream contains additional
data, such as destination addresses and word counts. A small
program called a boot kernel (described on page 1-14) parses the boot
stream and initializes memories accordingly. The boot kernel runs on the
target processor. Depending on the architecture, the boot kernel may execute
from on-chip boot RAM or may be preloaded from the PROM
device into on-chip SRAM and execute from there.
The loader utility generates the boot stream from the linker output (an
executable file) and stores it to file format that can be burned into the
PROM.
Host Boot Mode
In this scheme, the target processor is a slave to a host system. After reset,
the processor delays program execution until the slave gets signalled by the
host system that the boot process has completed. Depending on hardware
capabilities, there are two different methods of host booting. In the first
case, the host system has full control over all target memories. The host
halts the target while initializing all memories as required. In the second
case, the host communicates by a certain handshake with the boot kernel
running on the target processor. This kernel may execute from on-chip
ROM or may be preloaded by the host devices into the processor’s SRAM
by any bootstrapping scheme.
The loader/splitter utility generates a file that can be consumed by the
host device. It depends on the intelligence of the host device and on the
target architecture whether the host expects raw application data or a formatted
boot stream.
VisualDSP++ 4.5 Loader and Utilities Manual 1-13