May 2014
Intermediate to advanced
320 pages
13h 41m
English
Content preview from Servicing Personal Computers, 3rd Edition
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Microcomputer systems 13
6502 microprocessor
The 6502 is packed in a 40-pin DIL encapuslation, as shown in Figure 1.9. The functions of
the principal signal lines are summarized below:
ove
RDYC
ΦΐΕ
IRQC
NCC
NMlC
SYNCH
+5VC
AOC
AlC
A2C
A3C
A4C
A5C
A6C
A7C
A8C
A9C
AlOC
A11C
1· ^ 40
p 21
DRÊS
Ι]Φ2
Uso
ΙΙΦ0
DNC
DNC
DR/W
UDO
DD1
DD2
DD3
HUA
DD5
DD6
ÖD?
pA15
ΠΑ14
ΠΑ13
ΠΑ12
□
ov
Figure 1.9. 6502 pin connections
A0-A15 16-bit tri-state address bus.
D0-D7 8-bit tri-state data bus.
R/W Controls the direction of data transfer between the CPU and support devices. Output, high to
read and low to write. All transitions on this line occur during phase 1 cloc ...