Chapter 14. Queued Serial Peripheral Interface (QSPI) Module
14-15
Programming Model
14.5.8 Programming Example
The following steps are necessary to set up the QSPI 12-bit data transfers and a QSPI_CLK
of 4.125 MHz. The QSPI RAM is set up for a queue of 16 transfers. All four QSPI_CS
signals are used in this example.
1. Enable all QSPI_CS pins on the MCF5272. Write PACNT with 0x0080_1000 to
enable QSPI_CS1 and QSPI_CS3. Write PDCNT with 0x0000_0030 to enable
QSPI_CS2.
2. Write the QMR with 0xB308 to set up 12-bit data words with the data shifted on the
falling clock edge, and a clock frequency of 4.125 MHz (assuming a 66-MHz
CLKIN).
3. Write QDLYR with the desired delays.
4. Write QIR with 0xD00F to enable write collision, abort bus errors, and clear any
interrupts.
15
14
13
12
11
8
7
0
Field
CONT
BITSE
DT
DSCK
QSPI_CS
–
Reset
Undefined
R/W
Write Only
Address
QAR[ADDR]
Figure 14-10. Command RAM Registers (QCR0–QCR15)
Table 14-7 gives QCR field descriptions.
Table 14-7. QCR0–QCR15 Field Descriptions
Bits
Name
Description
15
CONT
Continuous.
0 Chip selects return to inactive level defined by QWR[CSIV] when transfer is complete.
1 Chip selects remain asserted after transfer is complete.
14
BITSE
Bits per transfer enable.
0 Eight bits
1 Number of bits set in QMR[BITS]
13
DT
Delay after transfer enable.
0 Default reset value.
1 The QSPI provides a variable delay at the end of serial transfer to facilitate interfacing
with peripherals that have a latency requirement. The delay between transfers is
determined by QDLYR[DTL].
12
DSCK
Chip select to QSPI_CLK delay enable.
0 Chip select valid to QSPI_CLK transition is one-half QSPI_CLK period.
1 QDLYR[QCD] specifies the delay from QSPI_CS valid to QSPI_CLK.
11–8
QSPI_CS
Peripheral chip selects. Used to select an external device for serial data transfer. More
than one chip select may be active at once, and more than one device can be connected
to each chip select.
7–0
—
Reserved, should be cleared.
Summary of Contents for DigitalDNA ColdFire MCF5272
Page 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Page 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Page 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Page 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Page 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Page 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Page 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Page 338: ...13 44 MCF5272 User s Manual Application Examples ...
Page 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Page 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Page 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Page 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...