Chapter 14. Queued Serial Peripheral Interface (QSPI) Module
14-9
Programming Model
RAM. Each time the end of the queue is reached, QIR[SPIFE] is set. QIR[SPIF] is not
automatically reset. If interrupt driven QSPI service is used, the service routine must clear
QIR[SPIF] to abort the current request. Additional interrupt requests during servicing can
be prevented by clearing QIR[SPIFE].
There are two recommended methods of exiting wraparound mode: clearing
QWR[WREN] or setting QWR[HALT]. Exiting wraparound mode by clearing
QDLYR[SPE] is not recommended because this may abort a serial transfer in progress. The
QSPI sets SPIF, clears QDLYR[SPE], and stops the first time it reaches the end of the queue
after QWR[WREN] is cleared. After QWR[HALT] is set, the QSPI finishes the current
transfer, then stops executing commands. After the QSPI stops, QDLYR[SPE] can be
cleared.
14.5 Programming Model
The programming model for the QSPI consists of six registers. They are the QSPI mode
register (QMR), QSPI delay register (QDLYR), QSPI wrap register (QWR), QSPI interrupt
register (QIR), QSPI address register (QAR), and the QSPI data register (QDR).
There are a total of 80 bytes of memory used for transmit, receive, and control data. This
memory is accessed indirectly using QAR and QDR.
Registers and RAM are written and read by the CPU.
14.5.1 QSPI Mode Register (QMR)
The QMR register, shown in Figure 14-3, determines the basic operating modes of the
QSPI module. Parameters such as clock polarity and phase, baud rate, master mode
operation, and transfer size are determined by this register. The data output high impedance
enable, DOHIE, controls the operation of QSPI_Dout between data transfers. When
DOHIE is cleared, QSPI_Dout is actively driven between transfers. When DOHIE is set,
QSPI_Dout assumes a high impedance state.
NOTE:
Because the QSPI does not operate in slave mode, the master
mode enable bit, QMR[MSTR], must be set for the QSPI
module to operate correctly.
15
14
13
10
9
8
7
0
Field
MSTR
DOHIE
BITS
CPOL CPHA
BAUD
Reset
0000_0001_0000_0100
R/W
R/W
Address
MBAR + 0x00A0
Figure 14-3. QSPI Mode Register (QMR)
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
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Страница 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Страница 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...