5.1 Das U-Boot

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5.1.6U-Boot Init Script

The Das U-Boot boot loader comes with scripting facilities in the form of the Hush parser and the autoscript command. You should notice when first compiling the package that the Boundary Devices sample uses this to defer most board initialization to the MMC card. It does this by setting the CONFIG BOOTCOMMAND environment variable as follows.

#define CONFIG_BOOTCOMMAND

"mmcinit; fatload mmc 0 a0000000 init.scr ; autoscr a0000000 "

 

 

In English, this instructs U-Boot to initialize the MMC/SD card driver, load a file named init.scr from the card to address A0000000 (the start of RAM), and execute the script from that memory address. This little bit of scripting effectively passes all responsibility of what to do at boot time to the MMC card.

Think of it as a Das U-Boot version of AUTOEXEC.BAT.

The sample script is defined in u-boot-1.1.2/board/neon/init.script and performs the following steps.

1.Loads and displays a logo. The script looks for an image file named logo.bmp on the MMC/SD card. If found, it displays the logo on the LCD panel. We recommend that you place a splash image of a size matching your display on the MMC card. Note that the bitmap must be an 8-bit color bitmap.

2.Loads and runs Windows CE. Next, the script attempts to load NK.nb0 from the MMC/SD card and run it.

As mentioned earlier, the initialization has been mostly deferred to the MMC/SD card, so the compiled script (init.scr) must be placed on the card itself. The script is compiled using the Das U-Boot mkimage tool during the U-Boot build process.

The following list is a recap the expected content of the MMC/SD card when using the Boundary Devices initialization script.

Filename

Description

init.scr

Compiled initialization script

logo.bmp

8-bit color splash image

NK.nb0

Windows CE image

 

 

December 28, 2005

Revision 2.8

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Image 13
Sonic Alert 2.8 user manual Das U-Boot

2.8 specifications

Sonic Alert 2.8 is a state-of-the-art alarm clock designed primarily for individuals with hearing impairments or those who simply require a more robust waking mechanism. Engineered to deliver high-performance features and proprietary technologies, this device stands out as a reliable solution for a restful night and an efficient morning wake-up.

One of the hallmark features of Sonic Alert 2.8 is its powerful bed shaker. This vibration mechanism is designed to be placed under your pillow or mattress, providing a tactile wake-up signal. For individuals who may not respond to traditional auditory alarms, this function ensures that they start their day without being late for appointments or commitments.

The alarm clock also boasts an impressive sound output. With adjustable volume settings, users can customize the alarm sound to their preference, ranging from gentle melodies to loud, attention-grabbing beeps. This flexibility caters to diverse user needs, allowing for a more personalized waking experience.

In terms of visibility, Sonic Alert 2.8 integrates a bright, flashing strobe light that works in conjunction with the auditory alarms. This visual cue appeals to those who may have difficulty hearing and can be beneficial in noisy environments. The strobe light can be set to flash in a specific pattern or color, adding another layer of customization to the waking experience.

Moreover, Sonic Alert 2.8 is engineered with a user-friendly interface, featuring large, easy-to-read display numbers that are perfect for the visually impaired. The intuitive buttons allow for straightforward operation, including setting alarms or toggling through various functions with minimal hassle.

The device is also equipped with a battery backup feature, ensuring that alarms will still sound even during power outages. This functionality provides peace of mind, knowing that important morning engagements won't be missed.

Additionally, Sonic Alert 2.8 is constructed with durable materials, making it a reliable companion for years to come. The sleek design and compact size make it easy to place on any bedside table without taking up excessive space.

Overall, Sonic Alert 2.8 exemplifies innovation in alarm technology, combining advanced features and thoughtful design to cater to users' unique needs. Whether for the hard of hearing or anyone who simply desires a more effective wake-up method, this alarm clock is an ideal choice.