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System Specification for C65Fred BowenMarch 1, 1991

Contents of the Internal A and B Memory Address Busses Prior to Multiplexing

Signal "VMF" "CDF" "BMF" "BPF" "RF" "SPF" "SDF" "DAT" "COL"
IA0 VC0 RC0 RC0 RC0 RF0 SF0 SD0 DT0 A0
IA1 VC1 RC1 RC1 RC1 RF1 SF1 SD1 DT1 A1
IA2 VC2 RC2 RC2 RC2 RF2 SF2 SD2 DT2 A2
IA3 VC3 D0 VC0 VC0 RF3 1 SD3 DT3 A3
IA4 VC4 D1 VC1 VC1 RF4 1 SD4 DT4 A4
IA5 VC5 D2 VC2 VC2 1 1 SD5 DT5 A5
IA6 VC6 D3 VC3 VC3 1 1 D0 DT6 A6
IA7 VC7 D4 VC4 VC4 1 1 D1 DT7 A7
IA8 VC8 D5 VC5 VC5 1 1 D2 DT8 A8
IA9 VC9 D6 VC6 VC6 1 1 D3 DT9 A9
IA10 VMO/VC10 D7 VC7 VC7 RF5 VM0/1 D4 DT10 A10
IA11 VM1 CBO VC8 VC8 RF6 VM1 D5 DT11 1
IA12 VM2 CB1 VC9 VC9 RF7 VM2 D6 DT12 1
IA13 VM3 CB2 CB2/VC10 BE13/VC10 1 VM3 D7 BE13/DT13 1
IA14 VBO VB0 VB0 BE14 1 VB0 VB0 BE14 1
IA15 VB1 VB1 VB1 BE15 1 VB1 VB1 BE15 1
IA16 A16 A16 A16 A16 RF8 A16 A16 DT16 1
 
IB10 0/* * * * * * * * *
IB11 1 * * * * * * * 1
IB12 1 * * * * * * * 1
IB13 1 * * BO13/* * * * BO13/* 1
IB14 1 * * BO14 * * * BO14 1
IB15 1 * * BO15 * * * BO15 1
DMA 1 1 1 1 1 1 1 0 0

Legend :
VC = Video-Matrix Counter
RC = Row Counter
VM = Video Matrix Address
VB = Video Bank Address
CB = Character Generator Bank Address
RF = Refresh Counter
SF = Sprite Pointer Fetch Counter
SD = Sprite Data Fetch Counter
DT = Display Address Translator
BE = Bitplane Even Pointer
BO = Bitplane Odd Pointer
A = Address Out = Address in
D = Data fetched from previous fetch
* = "B" bus contents, same as "A" bus
xxx/yyy = contents for 320/640 pixel modes



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Read the small print. Last updated March 24, 2003.