1 mpc 555 memory controller and chip select. 2 how does keyboard know it’s memory map? processor...
Post on 24-Dec-2015
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1
MPC 555 Memory Controller and Chip
Select
2
How Does Keyboard Know It’s Memory Map?
processor
Keyboard
Data register 0xf0000000Control register R 0xf0000004
CS Base(0xf0000000)
#Bytes (256) Chip-Select 0 (CS0)
ChipEnable
3
MPC 555 Memory Controller
4
Memory Controller Block Diagram
5
Chip Select Based System Design
Device (Keyboard)
CSx
6
Chip Select with Peripheral
ACS: Address to CS SetupCSNT: Chip Select Negation Time
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Memory Controller Address Map
8
Chip Select Programming
9
CS Base Address Register bits
31 V Mapping is valid
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CS Programming: Option Registers
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Option Register bits
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Address Match Logic
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Example Device
Keyboard/Device foo memory map:
0x001f 0000 to 0x00ff ffff
CS1 programmed as: BR1[BA] 0x003e;
OR1[AM] 0x01fe;
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