Radio Shack TRS-80 Operation Manual page 99

Computer Graphics
Operation Manual
TRS-BO@
~~
fJfJI : GRON Turn on graphics display with waits on
fJfJ2
fJfJ3
PSECT fJFfJfJfJH
fJfJ4 GRON CALL INITG
fJfJ5
LD
A,fJFFH
fJfJ6
OUT (STATUS) ,A
fJfJ7
XOR A
fJfJ8
RET
fJfJ9 STATUS EQU
83H
fJlfJ
.
,
fJII : INITG -- Initialize Model III Graphics Board
fJl2
.
,
fJl3 INITG PUSH HL
fJl4 PUSH BC
fJl5
PUSH AF
fJl6
LD
A,lfJH
fJl7 OUT
(236) ,A
:Turn on port
fJl8 LD BC,15
fJl9 LD HL,DATA
fJ2fJ LOOP LD A,B
:Program CRTC chip for 8fJ by 24
fJ21 OUT
(136) ,A
fJ22 LD
A,(HL)
fJ23
OUT
(137),A
fJ24
INC HL
,/~
fJ25
INC B
fJ26
LD A,B
fJ27
CP
C
fJ28
JR NZ,LOOP
fJ29
POP AF
fJ3fJ
POP
BC
fJ31
POP HL
fJ32
RET
fJ33 DATA DEFB
99
fJ34
DEFB
8fJ
fJ35
DEFB
85
fJ36
DEFB
8
fJ37
DEFB
25
fJ38
DEFB 4
fJ39
DEFB 24
fJ4fJ
DEFB
24
fJ41
DEFB
fJ
fJ42
DEFB
9
fJ43
DEFB
fJ
fJ44
DEFB
fJ
fJ45
DEFB
fJ
fJ46
DEFB
fJ
fJ47
DEFB
fJ
fJ48
DEFB
fJ
fJ49 :
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