w65c265s Western Design Center, Inc., w65c265s Datasheet - Page 4

• Manufacturer Part Number: w65c265s
• Description: W65c265s 16?bit Microcontroller
• Manufacturer: Western Design Center, Inc.

1.1
The W65C816S 16-bit microprocessor is the fully static (may be stopped when PHI2 is high or low) version
of the popular W65C816 microprocessor used in the Apple IIgs personal computer system. The W65C816S
is compatible* with the NMOS 6502 and CMOS 65C02 used in many control applications and personal
computers.
The small die size and low power consumption of the W65C816S offer an excellent choice as a cost
effective 16-bit core microprocessor in one-chip microcomputers.
The W65C816S instruction set is compatible with the W65C02 and W65C02S, 8-bit microprocessors,
W65C802 and W65C816, 16-bit microprocessors.
1.2
The W65C265S 8K x 8 bit Read Only Memory (ROM) usually contains the user's program instructions,
interrupt vectors, and other fixed constants. The rom is programmable into the ROM during fabrication of
the W65C265S device.
1.3
The 576 x 8 bit Random Access Memory (RAM) contains the user program stack and is used for scratch
pad memory during system operation. This RAM is completely static in operation and requires no clock or
dynamic refresh. The data contained in RAM is read out nondestructively with the same polarity as the input
data.
1.4
1.4.1 The Bus Control Register (BCR) controls the various modes of I/O and external memory interface.
1.4.2 During power-up the value of BE defines the initial values of BCR0, BCR3 and BCR7, three bits in the
1.4.3 When BE goes high after RESB goes high the BCR sets up the W65C265S for emulation. Port 0 and
1.4.4 When BE goes high before RESB goes high, all bits in the BCR are "0".
1.4.5 After RESB goes high BE no longer effects the BCR register, and BCR may be written under software
The W65C816S Static 16-bit Microprocessor Core
1.4.6
8K x 8 ROM ($E000-$FFFF)
576 x 8 RAM ($0000-$01FF,$DF80-$DFBF)
Bus Control Register (BCR)
*except for the bit manipulation instructions that do not exist for the W65C816S
Table 1-1 and Figure 1-1 (following page) indicate how BCR7 and BE define the W65C265S
configuration.
BCR that set up the W65C265S for In-Circuit-Emulation (ICE) or normal mode.
1 are the address outputs, Port 2 is the data I/O bus and RUN is the multiplexed RUN
function. (see RUN pin function description).
control to reconfigure the W65C265S as desired.
SECTION 1 W65C265S FUNCTION DESCRIPTION
4