Late Award BIOS (4-5x PnP) post code list:
| Code | Meaning |
|---|---|
| C0 | 1. Turn off OEM specific cache, shadow 2. Initialize standard devices with default values: - DMA controller (8237) - Programmable Interrupt Controller (8259) - Programmable Interval Timer (8254) - RTC chip |
| C1 | Auto detection of onboard DRAM & Cache |
| C3 | 1. Test system BIOS checksum 2. Test the first 256K DRAM 3. Expand the compressed codes into temporary DRAM area including the compressed System BIOS & Option ROMs |
| C5 | Copy the BIOS from ROM into E0000-FFFFF shadow RAM so that POST will go faster |
| 01-02 | Reserved |
| 03 | Initialize EISA registers (EISA BIOS only) |
| 04 | Reserved |
| 05 | 1. Keyboard Controller Self Test 2. Enable Keyboard Interface |
| 06 | Reserved |
| 07 | Verifies CMOS's basic R/W functionality |
| BE | Program defaults values into chipset according to the MODBINable Chipset Default Table |
| 09 | 1. Program configuration register of Cyrix CPU according to the MODBINable Cyrix Register Table 2. OEM specific cache initialization (if needed) |
| 0A | 1. Initialize the first 32 interrupt vectors with corresponding interrupt handlers; Initialize INT No from 33-120 with Dummy (Spurious) interrupt handler 2. Issue CPUID instruction to identify CPU type 3. Early Power Management initialization (OEM specific) |
| 0B | 1. Verify the RTC time is valid or not 2. Detect bad battery 3. Read CMOS data into BIOS stack area 4. PnP initializations including (PnP BIOS only) - Assign CSN to PnP ISA card - Create resource map from ESCD 5. Assign IO & Memory for PCI devices (PCI BIOS only) |
| 0C | Initialization of the BIOS data area (40:00-40:FF) |
| 0D | 1. Program some of the chipset's value according to setup. (Early setup value program) 2. Measure CPU speed for display & decide the system clock speed 3. Video initialization including Monochrome, CGA, EGA/VGA. If no display device found, the speaker will beep. |
| 0E | 1. Initialize the APIC (Multi-Processor BIOS only) 2. Test video RAM (If Monochrome display device found) 3. Show message including: - Award logo - Copyright string - BIOS date code & Part No. - OEM specific sign on messages - Energy Star logo (Green BIOS only) - CPU brand, type & speed |
| 0F | DMA channel 0 test |
| 10 | DMA channel 1 test |
| 11 | DMA page registers test |
| 12-13 | Reserved |
| 14 | Test 8254 timer 0 counter 2 |
| 15 | Test 8259 interrupt mask bits for channel 1 |
| 16 | Test 8259 interrupt mask bits for channel 2 |
| 17 | Reserved |
| 19 | Test 8259 functionality |
| 1A-1D | Reserved |
| 1E | If EISA NVM checksum is good, execute EISA initialization (EISA BIOS only) |
| 1F-29 | Reserved |
| 30 | Detect base memory & extended memory size |
| 31 | 1. Test base memory from 256K to 640K 2. Test extended memory from 1M to the top of memory |
| 32 | 1. Display the Award Plug & Play BIOS extension message(PnP BIOS only) 2. Program all onboard super I/O chips(if any) including COM ports, LPT ports, FDD port according to setup value |
| 33-3B | Reserved |
| 3C | Set flag to allow users to enter CMOS setup utility |
| 3D | 1. Initialise keyboard 2. Install PS2 mouse |
| 3E | Try to turn on level 2 cache Note: Some chipset may need to turn on the L2 cache in this stage. But usually, the cache is turn on later in Post 61h |
| 3F-40 | Reserved |
| BF | 1. Program the rest of the chipset's value according to setup (later setup value program) 2. If auto configuration is enabled, programmed the chipset with predefined values in the MODBINable AutoTable |
| 41 | Initialize floppy disk drive controller |
| 42 | Initialize hard drive controller |
| 43 | If it is a PnP BIOS, initialize serial & parallel ports |
| 44 | Reserved |
| 45 | Initialize math coprocessor |
| 46-4D | Reserved |
| 4E | If there is any error detected (such as video, KB....), show all the error messages on the screen & wait for user to press key |
| 4F | 1. If password is needed, ask for password 2. Clear the Energy Star logo (Green BIOS only) |
| 50 | Write all the CMOS values currently in the BIOS stack are back into the CMOS |
| 51 | Reserved |
| 52 | 1. Initialize all ISA ROMs 2.Later PCI initializations(PCI BIOS only) - assign IRQ to PCI devices - initialize all PCI ROMs 3. PnP initializations (PnP BIOS only) - assign IO, Memory, IRQ & DMA to PnP ISA devices - initialize all PnP ISA ROMs 4. Program shadow RAM according to setup settings 5. Program parity according to setup setting 6. Power Management initialization - Enable/Disable global PM - APM interface initialization |
| 53 | 1. If it is not a PnP BIOS, initialize serial & parallel ports 2. Initialize time value in BIOS data area by translate the RTC time value into a timer tick value |
| 54-5F | Reserved |
| 60 | Setup virus protection (boot sector protection) functionality according to setup setting |
| 61 | 1. Try to turn on level 2 cache Note: if L2 cache is already turned on in POST 3D, this part will be skipped 2. Set the boot up speed according to setup setting 3. Last chance for chipset initialization 4. Last chance for Power Management initialization (Green BIOS only) 5. Show the system configuration table |
| 62 | 1. Setup daylight saving according to setup values 2. Program the NUM lock, typematic rate & typematic speed according to setup setting |
| 63 | 1. If there is any changes in the hardware configuration, update the ESCD information (PnP BIOS only) 2. Clear memory that have been used 3. Boot system via INT 19h |
| FF | Boot |