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External Bus Interface (EBI)
MPC5566 Microcontroller Reference Manual, Rev. 2
12-54
Freescale Semiconductor
shows a description of the states defined for the internal arbiter protocol.
shows the truth table for the internal arbiter protocol.
Table 12-22. Internal Arbiter State Descriptions
State
Description
Outputs
MCU owner idle
MCU controls the bus, but is not currently running a transaction
BG = 1, BB = hiZ
External owner
External master controls the bus; can be running a transaction or not
BG = 0, BB = hiZ
MCU bus wait
MCU controls the bus for the next transaction
Waiting for the external master to negate BB for the current transaction in progress
BG = 1, BB = hiZ
MCU owner busy
MCU controls the bus
Currently running a transaction
BG = 1, BB = 0 or 1
External bus wait
External master controls the bus for next transaction
Waiting for MCU to negate BB for the current transaction in progress
BG = 0, BB = 0 or 1
Table 12-23. Truth Table for Internal Arbiter
State
Outputs
Previous Inputs
External Status
Next State
BG
BB
1
BR
2
BB
3
MCU
internal
request
pending
(IRP)
4
External
has
higher
priority
(EHP)
5
MCU
external
transaction
in progress
(or starting
next cycle)
(ETP)
6
Recent
BG
(RBG)
7
MCU owner idle
1
hiZ
1
X
0
0
0
X
8
MCU owner idle
MCU owner idle
1
hiZ
X
X
0
1
0
X
9
External owner
MCU owner idle
1
hiZ
0
X
0
X
0
X
External owner
MCU owner idle
1
hiZ
0
X
X
1
0
X
External owner
MCU owner idle
1
hiZ
X
X
1
0
X
X
MCU owner busy
MCU owner idle
1
hiZ
1
X
1
X
X
X
MCU owner busy
MCU owner idle
1
hiZ
X
X
X
X
1
X
MCU owner busy
External owner
0
hiZ
X
X
0
X
X
10
X
11
External owner
External owner
0
hiZ
0
X
X
1
X
X
External owner
External owner
0
hiZ
X
X
1
0
X
X
MCU bus wait
External owner
0
hiZ
1
X
1
X
X
X
MCU bus wait
MCU bus wait
1
hiZ
X
0
X
12
X
X
MCU bus wait
MCU bus wait
1
hiZ
X
X
X
X
X
1
MCU bus wait
MCU bus wait
1
hiZ
X
1
X
X
X
0
MCU owner busy
MCU owner busy
1
0 or 1
13
1
X
X
X
1
MCU owner busy
MCU owner busy
1
0 or 1
1
X
1
X
X
X
MCU owner busy
MCU owner busy
1
0 or 1
X
X
1
0
X
X
MCU owner busy
MCU owner busy
1
0 or 1
0
X
X
1
1
X
External bus wait
Summary of Contents for MPC5566
Page 81: ...Introduction MPC5566 Microcontroller Reference Manual Rev 2 1 24 Freescale Semiconductor...
Page 135: ...Signal Description MPC5566 Microcontroller Reference Manual Rev 2 2 54 Freescale Semiconductor...
Page 189: ...Reset MPC5566 Microcontroller Reference Manual Rev 2 4 20 Freescale Semiconductor...
Page 603: ...Flash Memory MPC5566 Microcontroller Reference Manual Rev 2 13 38 Freescale Semiconductor...
Page 609: ...SRAM MPC5566 Microcontroller Reference Manual Rev 2 14 6 Freescale Semiconductor...
Page 1073: ...MPC5566 Microcontroller Reference Manual Rev 2 22 36 Freescale Semiconductor...
Page 1185: ...Nexus MPC5566 Microcontroller Reference Manual Rev 2 25 92 Freescale Semiconductor...