
9- 24
MC68341 USER’S MANUAL
MOTOROLA
QSPI commands beginning at any location in the queue. Therefore, the user in advance
is able to set up separate subqueues for different tasks within the QSPI RAM. By writing
to NEWQP, selection between the different subqueues within the QSPI RAM is
accomplished.
If wraparound mode is enabled by setting WREN and WRTO in SPCR2, NEWQP
assumes an additional function. When the end of the queue is reached, as determined
by ENDQP, the address contained in NEWQP is used by the QSPI to wrap around to
the first queue entry. The QSPI then re-executes the queued commands repeatedly
until halted.
9.5.4.4 QSPI CONTROL REGISTER 3 (SPCR3). SPCR3 contains parameters for
configuring the QSPI. The CPU can read and write this register; the QSPM has read-only
access.
SPCR3
$81E
15
14
13
12
11
10
9
8
0
LOOP
Q
HMIE
HALT
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
RESET:
00000000
Bits 15–11—Not Implemented
LOOPQ—QSPI Loop Mode
1 = Feedback path enabled
0 = Feedback path disabled
LOOPQ enables or disables the feedback path on the data serializer for testing. If
enabled, LOOPQ routes serial output data back into the data serializer, instead of
received data. If disabled, LOOPQ allows regular received data into the data serializer.
LOOPQ does not affect the QSPI output pins.
HMIE—HALTA and MODF Interrupt Enable
1 = HALTA and MODF interrupts enabled
0 = HALTA and MODF interrupts disabled
HMIE enables or disables QSPI interrupts to the CPU caused when either the HALTA
status flag or the MODF status flag in SPSR is asserted. When HMIE is set, the
assertion of either flag causes the QSPI to send a hardware interrupt to the CPU. When
HMIE is clear, the asserted flag does not cause an interrupt.
HALT—Halt
1 = Halt enabled
0 = Halt not enabled
This bit is used by the CPU to stop the QSPI on a queue boundary. The QSPI halts in a
known state from which it can later be restarted. When HALT is asserted by the CPU,
the QSPI finishes executing the current serial transfer (up to 16 bits) and then halts.
While halted, if the command control bit (CONT of the QSPI RAM) for the last command
was asserted, the QSPI continues driving the peripheral chip-select pins with the value
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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