185
BIOS POST Checkpoint Codes
The following table describes the checkpoints and associated beep codes, if any, that may occur during the POST portion of the BIOS.
Checkpoint | Beep Code | Description | |
Code | |||
|
| ||
|
|
| |
01h | One short |
| |
| beep before |
| |
| boot |
| |
|
|
| |
02h |
| Verify Real Mode. If the CPU is in protected | |
|
| mode, turn on A20 and pulse the reset line, | |
|
| forcing a shutdown 0. | |
|
| NOTE: Hook routine should not alter DX, | |
|
| which holds the powerup CPUID. | |
|
|
| |
03h |
| Disabel | |
|
|
| |
04h |
| Get CPU type from CPU registers and other | |
|
| methods. | |
|
| Save CPU type in NVRAM. | |
|
| NOTE: Hook routine should not alter DX, | |
|
| which holds the powerup CPUID. | |
|
|
| |
06h |
| Initialize system hardware. Reset the DMA | |
|
| controllers, disable video, clear any pending | |
|
| interrupts from the | |
|
| setup port B register. | |
|
|
| |
07h |
| Disable system ROM shadow and start to | |
|
| execute ROMEXEC code from the flash part. | |
|
| This task is pulled into the build only when | |
|
| the ROMEXEC relocation is installed. | |
|
|
| |
08h |
| Initialize chipset registers to the Initial POST | |
|
| Values. | |
|
|
|
