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MPC5553/MPC5554 Microcontroller Reference Manual, Rev. 5
Freescale Semiconductor
1-15
1.5.3
eDMA
The enhanced direct memory access (eDMA) controller is a second-generation module capable of
performing complex data movements via 64 (MPC5554) or 32 (MPC5553) programmable channels, with
minimal intervention from the CPU. The hardware micro architecture includes a DMA engine which
performs source and destination address calculations, and the actual data movement operations, along with
an SRAM-based memory containing the transfer control descriptors (TCD) for the channels. This
implementation is utilized to minimize the overall module size.
1.5.4
INTC
The interrupt controller (INTC) provides priority-based preemptive scheduling of interrupt requests,
suitable for statically scheduled real-time systems. The INTC allows interrupt request servicing from 308
(MPC5554)/212(MPC5553) interrupt sources.
For high priority interrupt requests, the time from the assertion of the interrupt request from the peripheral
to when the processor is executing the interrupt service routine (ISR) has been minimized. The INTC
provides a unique vector for each interrupt request source for quick determination of which ISR needs to
be executed. It also provides an ample number of priorities so that lower priority ISRs do not delay the
execution of higher priority ISRs. To allow the appropriate priorities for each source of interrupt request,
the priority of each interrupt request is software configurable.
When multiple tasks share a resource, coherent accesses to that resource must be supported. The INTC
supports the priority ceiling protocol for coherent accesses. By providing a modifiable priority mask, the
priority level can be raised temporarily so that no task can preempt another task that shares the same
resource.
Multiple processors can assert interrupt requests to each other through software settable interrupt requests
(by using application software to assert requests). These maskable interrupt requests can be used to split
the software into a high priority portion and a low priority portion for servicing the interrupt requests. The
high priority portion is initiated by a peripheral interrupt request, but then the ISR asserts a software
settable interrupt request to finish the servicing in a lower priority ISR.
1.5.5
FMPLL
The frequency modulated PLL (FMPLL) allows the user to generate high speed system clocks from an
8 MHz to 20 MHz crystal oscillator or external clock generator. Further, the FMPLL supports
programmable frequency modulation of the system clock. The PLL multiplication factor, output clock
divider ratio, modulation depth, and modulation rate are all software configurable.
1.5.6
EBI
The external bus interface (EBI) controls data transfer across the crossbar switch to/from memories or
peripherals in the external address space. The EBI also enables an external master to access internal
address space. The EBI includes a memory controller that generates interface signals to support a variety
of external memories. The EBI memory controller supports single data rate (SDR) burst mode flash,
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