Intel BONANZA S478 I875 ATX DDR BLKD875PBZLK User Manual

130 

 

Table 81 describes the lower nibble of the high byte and indicates the bus on which the routines are 
being executed. 

0 

Generic DIM (Device Initialization Manager) 

1 Onboard 

system devices 

2 

ISA devices  

3 EISA 

devices 

4 

ISA PnP devices 

5 PCI 

devices 

A 47 

Ω inductive speaker is mounted on the Desktop Board.  The speaker provides audible error 

code (beep code) information during POST. 

 

The location of the onboard speaker 

Figure 1, page 14 

Whenever a recoverable error occurs during POST, the BIOS displays an error message describing 
the problem (see Table 82).  The BIOS also issues a beep code (one long tone followed by two 
short tones) during POST if the video configuration fails (a faulty video card or no card installed) 
or if an external ROM module does not properly checksum to zero. 

An external ROM module (for example, a video BIOS) can also issue audible errors, usually 
consisting of one long tone followed by a series of short tones.  For more information on the beep 
codes issued, check the documentation for that external device. 

There are several POST routines that issue a POST terminal error and shut down the system if they 
fail.  Before shutting down the system, the terminal-error handler issues a beep code signifying the 
test point error, writes the error to I/O port 80h, attempts to initialize the video and writes the error 
in the upper left corner of the screen (using both monochrome and color adapters).