W65C02S Datasheet, PDF (36/40 Pages) List of Unclassifed Manufacturers – Microprocessor

The Western Design Center, Inc.
7 CAVEATS
Table 7-1 Microprocessor Operational Enhancements
W65C02S Datasheet
Function
Indexed addressing across page
boundary
Execution of invalid OpCodes.
Jump indirect, operand = XXFF.
Read/Modify/Write instruction at
effective address.
Decimal flag.
Flags after decimal operation.
Interrupt after fetch of BRK
instruction
Ready.
Read/Modify/Write instructions
absolute indexed in same page.
Oscillator.
Assertion of Ready (RDY) during
write operations.
Clock inputs.
Unused input-only pins.
NMOS 6502
Extra read of invalid address.
W65C02S
Extra read of last instruction byte.
Some terminate only by reset.
Results are undefined.
Page address does not increment.
One read and two write cycles.
All are NOP's (reserved for future use).
OpCode
Bytes Cycles
02,22,42,62,82
2
2
C2, E2
X3,OB-BB,EB,FB 1
1
44
2
3
54,D4,F4
2
4
5C
3
8
DC,FC
3
4
Page address increments, one additional
cycle.
Two read and one write cycle.
Indeterminate after reset.
Invalid N, V and Z flags.
Interrupt vector is loaded; BRK
vector is ignored.
Input.
Seven cycles.
Initialized to binary mode (D=0) after reset
and interrupts.
Valid flags. One additional cycle.
BRK is executed, and then interrupt is
executed.
Bi-directional, WAI instruction pulls low.
Six cycles.
Requires external active components. Crystal or RC network will oscillate when
connected between PHI2 and PHI10.
Ignored.
Stops processor during PHI2, and WAI
instruction pulls RDY low.
PHI2 is the only required clock.
PHI2 is the only required clock.
Must be tied to VDD.
Must be tied to VDD.
The BRK instruction for both the NMOS 6502 and 65C02 is a 2 byte instruction. The NMOS and CMOS devices
simply skips the second byte (i.e. doesn’t care about the second byte) by incrementing the program counter twice.
It is important to realize that if a return from interrupt is used it will return to the location after the second or
signature byte.
The Western Design Center, Inc.
W65C02S Datasheet
36