NXP Semiconductors MPC5644A, Reference Manual, Page: 556 / 1735

System Integration Unit (SIU)
MPC5644A Microcontroller Reference Manual, Rev. 6
556 Freescale Semiconductor
16.7.5 Internal multiplexing
The IMUX Select Registers (SIU_ISEL x ) provide selection of the eQADC external trigger inputs sources,
the SIU external interrupts, some of the eTPU inputs and the DSPI signals that are used in the serial and
parallel chaining of DSPI blocks.
16.7.5.1 eQADC external trigger input multiplexing
The six eQADC external trigger inputs can be connected to either an external pin, an eTPU channel, an
eMIOS channel or a PIT or RTI trigger. The input source for each eQADC external trigger is individually
specified in the ETISR, SIU_ISEL3 and SIU_ISEL9 registers. One of these inputs is in turn specified in
the IMUX Select Register 3 (SIU_ISEL3). An example of the multiplexing of an eQADC external trigger
input is given in
Figure 16-221 . As shown in the figure, the Trigger[0] input of the eQADC can be
connected to either the ETRIG[0] pin, the eTPU_A[30] channel or the eMIOS[10] channel or the output
of the mux, IMUX3. The inputs of IMUX3 can be some of the eTPU/eMIOS channels or PIT/RTI triggers
or External triggers.
Figure 16-221. eQADC trigger input multiplexing example
The remaining ADC trigger inputs are multiplexed in the same manner. Note that if an ETRIG input is
connected to an eTPU or eMIOS channel, the external pin used by that channel can be used by the alternate
function on that pin.
Along with the six eQADC external trigger inputs, there is one additional trigger input to ADC. The source
of that trigger is specified in IMUX Select Register 9 (SIU_ISEL9). It is similar to SIU_ISEL3, shown in
the above figure.
16.7.5.2 SIU external interrupt input multiplexing
The fifteen SIU external interrupt inputs can be connected to either external pins or to deserialized output
signals from a DSPI block. The input source for each SIU external interrupt is individually specified in the
External IRQ Input Select Register
1
(EIISR). An example of the multiplexing of an SIU external interrupt
input is given in Figure 16-222 . As shown in the figure, the IRQ[0] input of the SIU can be connected to
either the eMIOS[14]_IRQ[0]_eTPU_A[29]_GPIO[193] pin, the DSPI_B[0] deserialized output signal,
the DSPI_C[1] deserialized output signal or eMIOS[14] channel. The remaining IRQ inputs are
1. The EIISR is sometimes referred to as ISEL1.
ETISR[TSEL0]
ETRIG[0]
eTSEL0
eTPU_A[30]
eMIOS[10]
To ADC Trigger Input
SIU_ISEL3
RTI-Trigger
PIT-0/1/2/3-Trigger
ETRIG-0/3
eTPU_A-28/29/30/31
eMIOS-10/23