![](/images/new-backgrounds/1299418/299418141x1.webp)
Code | Beeps | POST Routine Description |
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46h | Check ROM copyright notice | |
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|
48h |
| Check video configuration against CMOS |
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49h |
| Initialize PCI bus and devices |
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|
4Ah |
| Initialize all video adapters in system |
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|
4Bh |
| QuietBoot start (optional) |
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|
4Ch |
| Shadow video BIOS ROM |
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|
4Eh |
| Display BIOS copyright notice |
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|
50h |
| Display CPU type and speed |
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|
51h |
| Initialize EISA board |
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|
52h |
| Test keyboard |
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54h |
| Set key click if enabled |
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58h | Test for unexpected interrupts | |
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|
59h |
| Initialize POST display service |
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|
5Ah |
| Display prompt “Press F2 to enter SETUP” |
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|
|
5Bh |
| Disable CPU cache |
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|
|
5Ch |
| Test RAM between 512 and 640 KB |
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|
60h |
| Test extended memory |
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|
62h |
| Test extended memory address lines |
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|
|
64h |
| Jump to User Patch1 |
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|
|
66h |
| Configure advanced cache registers |
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|
|
67h |
| Initialize Multi Processor APIC |
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|
|
68h |
| Enable external and CPU caches |
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|
|
69h |
| Setup System Management Mode (SMM) area |
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|
|
6Ah |
| Display external L2 cache size |
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|
|
6Bh |
| Load custom defaults (optional) |
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|
|
6Ch |
| Display |
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|
|
6Eh |
| Display possible high address for UMB |
|
| recovery |
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|
70h |
| Display error messages |
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|
|
72h |
| Check for configuration errors |
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|
|
76h |
| Check for keyboard errors |
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|
|
7Ch |
| Set up hardware interrupt vectors |
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|
|
7Eh |
| Initialize coprocessor if present |
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|
|
80h |
| Disable onboard Super I/O ports and IRQs |
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|
|
81h |
| Late POST device initialization |
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|
|
82h |
| Detect and install external RS232 ports |
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|
|
83h |
| Configure |
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|
|
84h |
| Detect and install external parallel ports |
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|
|
85h |
| Initialize |
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|
|
86h |
| |
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|
87h |
| Configure Motherboard Configurable Devices |
|
| (optional) |
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|
|
88h |
| Initialize BIOS Area |
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|
|
89h |
| Enable |
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|
|
8Ah |
| Initialize Extended BIOS Data Area |
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|
|
8Bh |
| Test and initialize PS/2 mouse |
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|
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Chapter 4 | 65 |