Queued Serial Multi-Channel Module
MPC561/MPC563 Reference Manual, Rev. 1.2
15-42
Freescale Semiconductor
executed again. SPE is not cleared by the QSPI. New receive data overwrites previously received data
located in the receive data segment.
Wraparound mode is properly exited in two ways:
•
The CPU may disable wrap-around mode by clearing WREN. The next time end of the queue is
reached, the QSPI sets SPIF, clears SPE, and stops.
•
The CPU sets HALT. This second method halts the QSPI after the current transfer is completed,
allowing the CPU to negate SPE. The CPU can immediately stop the QSPI by clearing SPE;
however, this method is not recommended, as it causes the QSPI to abort a serial transfer in
process.
15.6.8
Mode Fault
MODF is asserted by the QSPI when the QSPI is the serial master (MSTR = 1) and the slave select
(PCS0/SS) input pin is pulled low by an external driver. This is possible only if the PCS0/SS pin is
configured as input by QDDR. This low input to SS is not a normal operating condition. It indicates that
a multimaster system conflict may exist, that another MCU is requesting to become the SPI network
master, or simply that the hardware is incorrectly affecting PCS0/SS. SPE in SPCR1 is cleared, disabling
the QSPI. The QSPI pins revert to control by QPDR. If MODF is set and HMIE in SPCR3 is asserted, the
QSPI generates an interrupt to the CPU.
The CPU may clear MODF by reading SPSR with MODF asserted, followed by writing SPSR with a zero
in MODF. After correcting the mode fault problem, the QSPI can be re-enabled by asserting SPE.
The PCS0/SS pin may be configured as a general-purpose output instead of input to the QSPI. This inhibits
the mode fault checking function. In this case, MODF is not used by the QSPI.
15.7
Serial Communication Interface
The dual, independent, serial communication interface (DSCI) communicates with external devices
through an asynchronous serial bus. The two SCI modules are functionally equivalent, except that the
SCI1 also provides 16-deep queue capabilities for the transmit and receive operations. The SCIs are fully
compatible with other Freescale SCI systems. The DSCI has all of the capabilities of previous SCI systems
as well as several significant new features.
is a block diagram of the SCI transmitter.
is a block diagram of the SCI receiver.
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...