External Bus Interface
MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
9-35
Figure 9-26. Bus Arbitration Timing Diagram
9.5.7.4
Internal Bus Arbiter
The MPC561/MPC563 can be configured at system reset to use the internal bus arbiter. In this case, the
MPC561/MPC563 will be parked on the bus. The parking feature allows the MPC561/MPC563 to skip the
bus request phase, and if BB is negated, assert BB and initiate the transaction without waiting for BG from
the arbiter.
The priority of the external device relative to the internal MPC561/MPC563 bus masters is programmed
in the SIU module configuration register. If the external device requests the bus and the MPC561/MPC563
does not require it, or if the external device has higher priority than the current internal bus master, the
MPC561/MPC563 grants the bus to the external device.
describes the priority mechanism used by the internal arbiter.
CLKOUT
BR0
BG1
ADDR[8:31]
BG0
BR1
Master 0
“Turns On” and
Drives Signals
Master 0
Negates
BB
and “Turns Off”
(Three-state Controls)
BB
TS
TA
Master 1
“Turns On” and
Drives Signals
and Attributes
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...