MPC563XM Reference Manual, Rev. 1
848
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
value in SRV1/2, the client will load the Red Line information into the appropriate resource. For
information on eTPU Red Line Bus configuration refer to
Section 23.3.3.4, “ETPUREDCR - eTPU Red
The eTPU does not include a Red Line Controller module, which is instantiated once in the system
integration. For details on Red Line bus protocol and definition of Red Line modules refer to IP Interface
- Red Line.
NOTE
Setting a timebase as client of itself is forbidden, and results are
unpredictable.
23.4.6.4
GTBE - Global Time Base Enable
GTBE bit in ETPUMCR register enables time bases in both engines, allowing them to be started
synchronously. GTBE is divided in two block interface signals: etpu_gtbe_out and etpu_gtbe_in. GTBE
bit sets etpu_gtbe_out, and etpu_gtbe_in enables time bases to start. The etpu_gtbe_out signal can be used
by MCU integration for synchronization between eTPU time bases and time bases from other modules. If
the GTBE bit in ETPUMCR must enable only the eTPU time bases, etpu_gtbe_out is simply connected to
etpu_gtbe_in. These two cases are shown in
. Synchronization logic can be as simple as an
OR or an AND logic gate.
Once etpu_gtbe_in transitions to 1, the Engine 1 Time Bases start 1 system clock earlier than Time Bases
in Engine 2, except when TCRCLK is selected as clock source or TCR1 when ETPUTBCR[TCR1CS]=1.
This happens independently of prescaler values as long as they are the same for both engines, because the
prescalers also freeze when etpu_gtbe_in = 0. Microcode can always write to TCR1/2 registers, with either
value of etpu_gtbe_in.
NOTE
The timebase prescalers are reset when the GTBE input is negated.