Power-On Sequence; Power-On Diagnostic Tests - HP Gt7725 - Compaq Thin Client Troubleshooting Manual

Power-On Sequence

At power-on, the flash boot block code initializes the hardware to a known state, then performs basic
power-on diagnostic tests to determine the integrity of the hardware. Initialization performs the following
functions:
1. Initializes CPU and memory controller.
2. Initializes VGA software.
3. Initializes and configures all PCI devices.
4. Initializes the video to a known state.
5. Initializes USB devices to a known state.
6. Performs power-on diagnostics. For more information, see
on page
7. The unit boots the operating system.

Power-On Diagnostic Tests

The Power-on diagnostics performs basic integrity tests of the hardware to determine its functionality
and configuration. If a diagnostic test fails during hardware initialization the unit simply stops. There are
no messages sent to video.
NOTE: You may try to restart the unit and run through the diagnostic tests a second time to confirm
the first shutdown.
The following table lists the tests that are performed on t5000 units.
Table 4-2 Power-On Diagnostic Test
Test
Boot Block Checksum
DRAM
Parallel Port
Serial Port
Timer
RTC CMOS battery
NAND flash device
27.
Description
Tests boot block code for proper checksum value
Simple write/read pattern test of the first 640k of memory
Initiates the port's driver and determines if the device is present
Tests the serial port using simple port verification test to determine if ports are present
Tests timer interrupt by using polling method
Tests integrity of RTC CMOS battery
Tests for proper NAND flash device ID present
Power-On Diagnostic Tests
Power-On Sequence 27