PXR40RM Datasheet, PDF (275/1434 Pages) Freescale Semiconductor, Inc – PXR40 Microcontroller

System Integration Unit (SIU)
An example of the multiplexing of an eQADC (EQADC_A) external trigger input is given below.
Extended trigger selection
SIU_ISEL5[cTSEL0_0[2:6]]
TXDC_ETRIG[0]_GPIO[244]
ETPUA[30] output channel
EMIOS[10] output channel
ETRIG[0]
SIU_ISEL5[cTSEL0_0[0:1]]
Figure 7-50. eQADC External Trigger Input Multiplexing
SIU_ISEL4-7 always provides one of four choices based on the most-significant two bits of each cTSEL
field. When those bits are 0b00, the extended trigger selection is chosen and the remaining bits in cTSEL
select among a longer list of trigger sources.
7.4.5.2 SIU External Interrupt Input Multiplexing
The sixteen SIU external interrupt inputs can be connected to either an external pin or to output signals
from a DSPI module. The input source for each SIU external interrupt is individually specified in the
external IRQ input select register (SIU_EIISR).
As shown in the following figure, the IRQ[0] input of the SIU can be connected to either the
IRQ[0]_GPIO[450] pin, the PCSB[0] input signal, the PCSC[1] deserialized output signal, or the PCSD[2]
deserialized output signal. The remaining IRQ inputs are multiplexed in the same manner. The inputs to
the IRQ from each DSPI module are offset by one so that if more than one DSPI module is connected to
the same external device type, a separate interrupt can be generated for each device. This also applies to
DSPI modules connected to external devices of a different type that have status bits in the same bit location
of the deserialized information.
An example of the multiplexing of an SIU external interrupt input is given in Figure 7-51.
IRQ[0]_GPIO[450]
DSPI B[0] serialized input
DSPI C[1] serialized input
DSPI D[2] serialized input
ESEL[0]
ESEL[1]
IRQ[0]
Figure 7-51. DSPI Serialized Input Multiplexing
7.4.5.3 Multiplexed Inputs for DSPI Multiple Transfer Operation
Each DSPI module can be combined in a serial or parallel chain (multiple transfer operation). Serial
chaining allows SPI operation with an external device that has more bits than one DSPI module.
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
7-93