B&B Electronics PC Watchdog Timer Card ATXWDT Especificaciones descargar pdf (Pagina 76)

Intel

SRMK2 Internet Server Technical Product Specification 76

This token is of the following format:

MSB LSB

15 … 12 11 … 0

# of bits available - 1 Bit offset from start of CMOS of first bit

The most significant 4 bits will be equal to the number of CMOS bits available minus 1. This field

will be equal to 3 since there are four CMOS bits available. The 12 least significant bits will

define the position of the CMOS bit in the RTC (Real Time Clock). This will be a bit address

rather than a byte address. The CMOS byte location is 1/8th of the 12-bit number, and the

remainder will be the starting bit position within that byte. For example, if the 12-bit number is

0109h, the user binary can use bit 1 of CMOS byte 0108h/8, or 021h.

The following code fragment shows the header and format for a User Binary:

.286

db 55h,0AAh,10h ; USER binary signature is 55h,AAh

; 10h = size of user binary area

; 8k = 10h*512 bytes

MyCode PROC FAR ; MUST be a FAR procedure

;*** Use for normal CU controllable user binaries

;

; RETF ; Signal to BIOS that what follows

; is a standard user binary

; that will be used if the Scan User

; Flash CU selection is enabled.

;***

;*** Use for Mandatory user binaries

;

; db 0CBh ; Signal to BIOS that what follows

; is a user binary that

;***

db 04h ; Bit map to define call points, a

; one in any bit specifies that the

; BIOS will be called at that scan

; point in POST (scan points to be

; defined

;*** jump table for each scan point

JMP scanpoint_01h ; follows a list of 8 transfer

JMP scanpoint_02h ; addresses, one for each bit in the

JMP scanpoint_04h ; bitmap. In all likelihood, only

JMP scanpoint_08h ; one of these will be used, earlier

JMP scanpoint_10h ; entries must be present, later can

JMP scanpoint_20h ; be omitted if desired.

JMP scanpoint_40h

JMP scanpoint_80h

;* it is extremely important that this table's assembled code appears

;* as a jump table in real mode (jmps must be e9 xx 00 00) for each entry.

;* some assemblers will change the jmp to eb xx yy 00 00 or do a long

;* jump eb xx yy 00 00 00 00 which will create incorrect offsets. That is

;* why the .286 directive was used with masm 6.11. .586p is used to insert

;* instructions that do not appear in the 286 instruction set and to maintain

;* the offsets in the table.

; In this example since the mask is defined as 04h only scanpoint_04h

; will be executed during post. This happens to occur just before video

1 2 ... 71 72 73 74 75 76 77 78 79 80 81 ... 114 115

Comentarios a estos manuales

Sin comentarios

B&B Electronics PC Watchdog Timer Card ATXWDT Especificaciones Pagina 76

Comentarios a estos manuales

Relacionado con productos y manuales para Redes B&B Electronics PC Watchdog Timer Card ATXWDT