MPC563XM Reference Manual, Rev. 1
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Freescale Semiconductor
Preliminary—Subject to Change Without Notice
available for use in an alternate function by another block of the MCU. Single Master Mode is entered
when EXTM=0 and MDIS=0 in the EBI_MCR.
13.2.3.2
External Master Mode
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.
External Master Mode operation is described in
Section 13.5.2.10, “Bus Operation in External Master
13.2.3.3
Module Disable Mode
The Module Disable Mode is used for MCU power management. The clock to the non-memory mapped
logic in the EBI can be stopped while in Module Disable Mode. Logic on the MCU external to the EBI is
needed to fully implement the Module Disable Mode (to shut off the clock). Internal master requests made
to the external bus in Module Disable Mode are terminated with transfer error (internally, no external TEA
assertion). External master requests in Module Disable Mode are ignored (no external TEA assertion, so
access may hang or timeout). Module Disable Mode is entered when MDIS=1 in the EBI_MCR.
13.2.3.4
Stop Mode
The EBI supports the IPI Green-Line Interface Stop Mode mechanism used for MCU power management.
When a request is made to enter Stop Mode (controlled in SoC logic outside EBI), the EBI block completes
any pending bus transactions and acknowledges the stop request. After the acknowledgement, the system
clock input may be shut off by the clock driver on the MCU. While the clocks are shut off, the EBI is not
accessible. While in stop mode, accesses to the EBI from the internal master will terminate with transfer
error (internally, no external TEA assertion). External master requests in Stop Mode are ignored (no
external TEA assertion, so access may hang or timeout).
13.2.3.5
Slower-Speed Modes
In slower-speed modes, the external CLKOUT frequency is divided (by 2, 3, etc.) compared with that of
the internal system bus. The EBI behavior remains dictated by the mode of the EBI, except that it drives
and samples signals at the CLKOUT frequency rather than the internal system frequency. This mode is
selected by writing a clock control register in a block outside of the EBI. Refer to the device-specific SoC
Guide to see which slower-speed modes are available for a particular MCU (1/2, 1/3, etc.).
13.2.3.6
16-Bit Data Bus Mode
For MCUs that have only 16 data bus signals pinned out, or for systems where the use of a different
multiplexed function (e.g. GPIO) is desired on 16 of the 32 data pins, the EBI supports a 16-bit Data Bus
Mode. In this mode, only 16 data signals are used by the EBI. The user can select which 16 data signals
are used (DATA[0:15] or DATA[16:31]) by writing the D16_31 bit in the EBI_MCR.