w65c134s Western Design Center, Inc., w65c134s Datasheet - Page 6

• Manufacturer Part Number: w65c134s
• Description: W65c134s 8-bit Microcontroller
• Manufacturer: Western Design Center, Inc.

1.5
Chip Select Enable Register PCS3)($0007)
1.5.1
1.5.2
1.5.3
PCS is the Port 3 Chip Select Register. The PCS allows each individual chip select to be
active or non-active. When PCS30-PCS37 are equal to a "1", then CS0B to CS7B will be
active. When CS1B is active, the defined memory space for CS3B and/or CS6B is reduced.
It is reduced by the memory space 0100-011F for CS1B. When CS2B is active, the defined
memory space for CS3B and/or CS6B is reduced. It is reduced by the memory space
0120-013F for CS2B.
CS7B is automatically enabled when BCR7=1.
The W65C134S will use the internal RAM as stack when PCS33 and PCS36 are disabled. If
PCS33 or PCS36 are enabled then the off chip stack is used.
CS7B
7
BCR7
0
0
1
1
Figure 1-2 Bus Control Register (BCR) ($001B)
CS6B
6
BE
0
1
0
1
Table 1-1 BCR7 and BE Control
CS5B
Internal ROM External Processor (DMA)
Internal ROM Internal Processor
External ROM External Processor (DMA)
External ROM Internal Processor
5
Figure 1-3 Chip Select Enable Register
CS4B
4
W65C134S Configuration
CS3B
3
CS2B
2
CS1B
1
CS0B
0
6