1. MPC 555 Memory Controller and Chip Select

2. How Does Keyboard Know It’s Memory Map?
#Bytes (256)
Chip-Select 0 (CS0)
CS Base(0xf )
processor
Keyboard
Chip
Enable
0xf
Data register
Control register R
0xf

3. MPC 555 Memory Controller

4. Memory Controller Block Diagram

5. Chip Select Based System Design
CSx
Device (Keyboard)

6. Chip Select with Peripheral
ACS: Address to CS Setup
CSNT: Chip Select Negation Time

7. Memory Controller Address Map

8. Chip Select Programming

9. CS Base Address Register bits31 V
Mapping is valid

10. CS Programming: Option Registers

11. Option Register bits

12. Address Match Logic

13. Example Device Keyboard/Device foo memory map:
0x001f 0000 to 0x00ff ffff
CS1 programmed as: BR1[BA]  0x003e;
OR1[AM]  0x01fe;