MPC 555 Memory Controller and Chip Select

How Does Keyboard Know It’s Memory Map? #Bytes (256) Chip-Select 0 (CS0) CS Base(0xf0000000) processor Keyboard Chip Enable 0xf0000000 Data register Control register R 0xf0000004

MPC 555 Memory Controller

Memory Controller Block Diagram

Chip Select Based System Design CSx Device (Keyboard)

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

Memory Controller Address Map

Chip Select Programming

CS Base Address Register bits 31 V Mapping is valid

CS Programming: Option Registers

Option Register bits

Address Match Logic

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