
External Bus Interface (EBI)
MPC5566 Microcontroller Reference Manual, Rev. 2
12-4
Freescale Semiconductor
•
Bus monitor
— User selectable
— Programmable timeout period (with 8 external bus clock resolution)
•
Port size configuration per chip select (16 or 32 bits)
•
Port size for calibration chip select is 16 bits
•
Configurable wait states (via chip selects)
•
Four chip select (CS[0:3]) signals
•
Write/byte enable (WE/BE) signals depend on the package: 416 BGA: four signals (WE/BE[0:3])
•
Support for dynamic calibration with up to four calibration chip selects (CAL_CS[0:3])
•
Configurable bus speed modes (½ or ¼ of the system clock frequency)
•
Module disable modes for power savings
•
Optional automatic CLKOUT gating to save power and reduce EMI
•
Compatible with MPC5xx external bus
Section 12.4.1.17, “Compatible with MPC5xx External Bus (with Some Limitations)
.”
12.1.4
Modes of Operation
The mode of the EBI is determined by the MDIS and EXTM bits in the EBI_MCR. See
“EBI Module Configuration Register (EBI_MCR)
” for details. Configurable bus speed modes and debug
mode are modes that the MCU can enter, in parallel to the EBI being configured in one of its
module-specific modes.
12.1.4.1
Single Master Mode
In single master mode, the EBI responds to internal requests matching one of its regions, but ignores all
externally-initiated bus requests. The MCU is the only master allowed to initiate transactions on the
external bus in this mode; therefore, it acts as a parked master and does not have to arbitrate for the bus
before starting each cycle. The BR, BG, and BB signals are not used by the EBI in this mode, and are
available for use in an alternate function by another module of the MCU. Single master mode is entered
when EXTM = 0 and MDIS = 0 in the EBI_MCR.
12.1.4.2
External Master Mode
When the MCU is in external master mode, the EBI responds to internal requests matching one of its
regions, and also to external master accesses to internal address space. In this mode, the BR, BG, and BB
signals are all used by the EBI to handle arbitration between the MCU and an external master. External
master mode is entered when EXTM = 1 and MDIS = 0 in the EBI_MCR register.
The MPC5566 has arbitration pins (BB, BR, BG), therefore dual-master operation (multiple masters
initiating external bus cycles) is supported. A multi-MCU system with one master and one slave is
supported. In a dual-controller system, if the EBI is configured to internal arbitration (EARB = 0 in
EBI_MCR), it must be used as the system master. If configured to external arbitration (EARB = 1 in
EBI_MCR), it must be the system slave.
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...