IBM PC CONVERTIBLE Technical Reference page 74

06CD FE 06 0093 R INC LOW_BALCTR ; PROCESS INTERRUPT
0601 EB 73 JMP SHORT LOWBEND
; NO INTERRUPTS IN SERVICE. SIGNAL LOW BATTERY.
0603 L4:
0603 80 OE 0015 R 80 OR BALSTATUS,LOW_BALSIG ; SET LOW BTRY SGNL FLAG ON
0608 E8 076E R CALL NMLCYCLE ; CYCLE NMI AND RESTORE INT FLAGS
SOUND THE 3 BEEPS
06DB C6 06 009 R 78 MOV LOW_BALCTR,120
SET 2 MINUTE COUNTER
3 BEEPS - LOOP COUNT
FORCE SPEAKER ON
06EO B9 0003
06E3 E8 0759 R
06E6 BB OODF
06E9
06E9 51
06EA B9 0090
06ED E8 0000
06FO 2B C9
06F2 E2 FE
06F4 59
06F5 E2 F2
06F7 E8 0762
06FA E4 61
06FC 24 F7
06FE E6 61
MOV CX,3
CALL SPKR_ON
MOV BX,223
LOW_BEEP _LOOP:
PUSH CX
MOV CX,144
CALL KB_NOISE
CX,CX
SHORT BEEP (.25 SECONDS)
SAVE LOOP COUNT
1/2 CYCLE FOR 890 HZ TONE
SOUND SPEAKER
$
250 MS OELAY BETWEEN BEEPS
CX RESTORE LOOP COUNT
LOW_BEEP _LOOP
SPKR_RESTORE RESTORE SPEAKER ENABLE
AL,NMLCNTL
AL,NOT DISJ.LARM RE-ENABLE ALARM NMI
NMLCNTL,AL
0700 80 OE 001 R 40
SUB
LOOP
POP
LOOP
CALL
IN
AND
OUT
OR BALSTATUS,LOW_BALHOLD ; SET BIT FOR WAITING FOR KEY
0705
0705 B8 4104
0708 BB 4000
070B 1 E
070C 07
0700 BF 0015 R
0710 CD 15
THIS LOOP WAITS FOR A KEY TO BE PRESSED. WHILE WAITING THE SYSTEM SLEEPS.
ALSO, WHILE WAITING IN THIS LOOP, THE INTERRUPTS WILL BE PROCESSED. THE
UPDATE ENDED INTERRUPT WHICH CALLS THE LOW BATTERY ROUTINE WILL INTERRUPT
OUT EVERY SECOND. TO EXIT THIS LOOP, EITHER A KEY IS PRESSED, EXTERNAL
POWER IS APPLIED OR THE TWO MINUTE COUNTER GOES TO O. BY APPLYING EXTERNAL
POWER (SEE LOJ.) OR BY THE TWO MINUTE COUNTER GOING TO 0 (SEE L2) WILL
FORCE OFF THE WAITING FOR KEY FLAG. IF THE TWO MINUTE COUNTER GOES TO 0,
THE SYSTEM WILL SET UP TO SUSPENO.
MOV
MOV
PUSH
POP
MOV
INT
; LOOP UNTIL KEY PRESSED
AX,4104H ; FUNCTION 41H, AL=04=RETURN IF ZERO
BX, LOW_BALHOLD*100H ; BH=LOW_BALHOLD, BL=O=NO TIME OUT
OS ; MAKE ES:DI POINT TO BALSTATUS
ES ,
DI,OFFSET BALSTATUS ;
15H ; SLEEP UNTI L KEY HIT
0712 F6 06 0015 R 40 TEST
JZ
JMP
BALSTATUS,LOW_BALHOLD ; BIT IS OFF IF KEY WAS PRESSED
0717 74 02
0719 EB EA
071B
071B 80 3E 0093 R 00
0720 75 12
0722 BA 03F2
0725 2A CO
0727 EE
L5:
CMP
JNE
MOV
SUB
OUT
L5 KEY PRESSED EXIT LOOP
LOW_KB_LOOP KEEP LOOPING
LOW_BALCTR,O
L6
DX,ORIVE_CNTL
AL,AL
DX,AL
CTR = 0 FORCE SUSPEND SET UP
NO, JUMP ON
TURN OFF DISKETTE MOTORS
THESE VARIABLES ARE INITIALIZED TO VALUES THAT CAUSES THE SYSTEM TO TURN
OFF WHEN RETURNING TO CALLER(RTCJ.LARM_NMI).
0728
072E
0734
0734
0737
073C
C7 06 0067 R 0000
C7 06 0069 R 0001
E8 0000 E
80 26 0015 R OF
073C BO 00
073E E6 74
0740 E4 75
0742 OC 60
MOV
MOV
L6:
CALL
AND
DSP_BLANK_CTR,O
SYS_OFF _CTR,1
KEY PRESSED OR CTR=1
DISABLE_NMI ; DISABLE NMI
BALSTATUS,NOT LOW_BALPEND ; TURN OFF LOW BAT PEND FLAG
L_PANEL_ON: TURN PANEL ON BEFORE EXITING
MOV AL, LCDJUNCT
OUT LCD_INDX,AL ACCESS LCDC CONTROL REGISTER
IN AL,LCD_DATA ; READ LCDC CONTROL REGISTER
OR AL,PANEL_ENABLE+SYNCENABLE ; FORCE PANEL ON
ROM BIOS 2-49