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Number
of ROMs to replace: 
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ROM Version Info
Frogger Freeplay
is compatible with all ROM versions.
Product Info
| EPROM type: |
2732
4k x 8 |
| Freeplay
DIP Setting: |
SW4=OFF,SW5=OFF |
| Replaces
Locations: |
IC5,
IC8 |
Hardware
Compatibility
Frogger Freeplay
only works with SEGA/Gremlin
hardware. It will not work with Konami
hardware. See below.
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Your PCB needs to be
SEGA/Gremlin, like the one shown above
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Konami
PCBs are not supported!
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Self Test
mode features:
- Test RAM locations
- IC19,IC22
$8000-$83FF
- IC20,IC21
$8400-$87FF
- Test ROM locations
- IC5 $0000-$0FFF
- IC6 $1000-$1FFF
- IC7 $2000-$2FFF
- IC8 $3000-$3FFF
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Peek at the Code
Here is a grab of Frogger code with my comments.
;----------------------------------------------------
; Check if Player Earned Free Life
;----------------------------------------------------
L0937: LD HL,(L0EDE) ; Get Score Threshold
SBC HL,DE ; Compare to Player's score
JR Z,L0940 ; Scores are identical, so award free guy
JR NC,L0959 ; Threshold not met, so skip ahead
L0940: LD (083CFh),A ; Clear Last Guy Marker (A = 0)
INC A ; A = 1
LD (BC),A ; Mark that Player has received free guy
DEC C ; BC = Number of Lives (83E5/83E6)
DEC C ; BC = Number of Lives (83E5/83E6)
LD A,(BC) ; Get number of lives
INC A ; Award 1 free life
LD (BC),A ; Update number of lives
;----------------------------------------------------
; Print Extra Frog
;----------------------------------------------------
LD HL,0ABDEh ; HL = Screen location for Frogs/Lives
LD BC,0FFE0h ; BC = Subtract 32 (move 1 RIGHT)
L0950: ADD HL,BC ; Move RIGHT 1 location for each live
DEC A ; Count number of live
JR NZ,L0950 ; Loop back until at location of new Frog
LD (HL),04Dh ; Print character = FROG
LD A,007h ; Sound #7: Extra Frog Sound
RST 18h ; Play Extra Frog Sound
;----------------------------------------------------
; Check if Player has High Score
;----------------------------------------------------
L0959: LD HL,(083EFh) ; HL = High Score
OR A ; Clear carry
SBC HL,DE ; Is this score higher than High Score?
RET NC ; No, so just return
;----------------------------------------------------
; Assign New High Score
;----------------------------------------------------
LD (083EFh),DE ; Update with new High Score
RET ; Return
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