Dim Code Checkpoints - Acer Aspire Z1650 Service Manual

Checkpoint Description
52 Updates CMOS memory size from memory found in memory test. Allocates memory for
Extended BIOS Data Area from base memory. Programming the memory hole or any kind
of implementation that needs an adjustment in system RAM size if needed.
60 Initializes Num-Lock status and programs the KBD typematic rate.
75 Initialize Int-13 and prepare for IPL detection.
78 Initializes IPL devices controlled by BIOS and option ROMs.
7A Initializes remaining option ROMs.
7C Generate and write contents of ESCD in NVRam.
84 Log errors encountered during POST.
85 Display errors to the user and gets the user response for error.
87 Execute BIOS setup if needed / requested. Check boot password if installed.
8C Late POST initialization of chipset registers.
8E Program the peripheral parameters. Enable/Disable NMI as selected.
90 Late POST initialization of system management interrupt.
A0 Check boot password if installed.
A1 Clean-up work needed before booting to OS.
A2 Takes care of runtime image preparation for different BIOS modules. Fill the free area in
F000h segment with 0FFh. Initializes the Microsoft IRQ Routing Table. Prepares the
runtime language module. Disables the system configuration display if needed.
A4 Initialize runtime language module. Display boot option popup menu.
A7 Displays the system configuration screen if enabled. Initialize the CPU's before boot, which
includes the programming of the MTRR's.
A8 Prepare CPU for OS boot including final MTRR values.
A9 Wait for user input at config display if needed.
AA Uninstall POST INT1Ch vector and INT09h vector. Deinitializes the ADM module.
AB Prepare BBS for Int 19 boot.
AC End of POST initialization of chipset registers.
B1 Save system context for ACPI.
00 Passes control to OS Loader (typically INT19h).

DIM Code Checkpoints

The Device Initialization Manager (DIM) gets control at various times during BIOS POST to initialize different
system busses. The following table describes the main checkpoints where the DIM module is accessed.
Checkpoint Description
2A Initialize different buses and perform the following functions: Reset, Detect, and Disable
(function 0); Static Device Initialization (function 1); Boot Output Device Initialization
(function 2). Function 0 disables all device nodes, PCI devices, and PnP ISA cards. It also
assigns PCI bus numbers. Function 1 initializes all static devices that include manual
configured onboard peripherals, memory and I/O decode windows in PCI-PCI bridges, and
noncompliant PCI devices. Static resources are also reserved. Function 2 searches for and
initializes any PnP, PCI, or AGP video devices.
38 Initialize different buses and perform the following functions: Boot Input Device
Initialization (function 3); IPL Device Initialization (function 4); General Device Initialization
(function 5). Function 3 searches for and configures PCI input devices and detects if
system has standard keyboard controller. Function 4 searches for and configures all PnP
and PCI boot devices. Function 5 configures all onboard peripherals that are set to an
automatic configuration and configures all remaining PnP and PCI devices.
Aspire Z1650 AIO Computer Service Guide 83