User's Manual

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Device System Configuration Information
LogicLoader (LoLoTM)
LogicLoader Overview
The LogicLoader (LoLo) is a bootloader/firmware-monitor program developed by Logic Product
Development. LogicLoader is designed to initialize an embedded device, load and bootstrap an
operating system, and provide a low-level firmware monitor with debugging functionality.
LogicLoader Basics
Most operating systems rely on an underlying bootloader to initialize a device from its reset condition. In
general, operating systems are designed with the assumption that the system will be in a specific pre-
defined state before the operating system is started. Some example assumptions might be that system
RAM has been initialized and cleared, processor interrupts are disabled, and a timer has been
initialized to provide a system tick for the OS. The LogicLoader program initializes Logic Product
Development’s SOM platforms and prepares them for use by an operating system.
Another basic function of LogicLoader is the capability to upgrade device software (flash memory, CPLD
firmware, serial EEPROM contents) after deployment. This “in-field upgrade” ability requires a
bootloader program that is capable of loading software images from various sources as well as
committing loaded images to non-volatile memory. LogicLoader implements this by giving the system
the ability to load system software from flash memory, a CompactFlash storage card, a Local Area
Network, or even from a device attached to the system’s serial port. LogicLoader also has the ability to
upgrade an existing operating system residing in system flash.
LogicLoader was developed to fulfill the need for an OS and processor independent bootloader that can
interface with a variety of hardware transports. The GNU development tool chain used to build
LogicLoader is cross-platform capable.
Using LogicLoader for Debugging
LogicLoader implements a feature-rich firmware monitor. Included with LoLo is the LogicLoader shell,
also known as “losh.” Losh is a command interpreter providing control over system state prior to
loading an OS image. It has features such as command recall, command-line editing, automated
control via scripting, and diagnostic routines.
Losh includes many commands designed specifically to help software and hardware engineers debug low-
level interfaces. For example, formatted data in arbitrary memory locations can be read from, and
written to, by using the 'x' and 'w' commands. Other commands run specific tests designed to verify
Logic’s SOM hardware platforms. All commands return a value to the command line that can be used
to conditionally evaluate the command result. Refer to the LogicLoader Command Description Manual
on Logic’s downloads page for a complete description of available commands.
Developers may code their own test programs using the provided GNU development tool chain and use the
LogicLoader to load and run their software. This provides the ability to verify and debug hardware
interfaces without the overhead of building, downloading, and running large operating system images.
Manufacturing Advantages with LoLo
LogicLoader can be used with a desktop software utility to load a device’s system software on the
manufacturing line. This utility is customizable to suit your desired transfer mechanism and additional