mcf5282 Freescale Semiconductor, Inc, mcf5282 Datasheet - Page 413

• Manufacturer Part Number: mcf5282
• Manufacturer: Freescale Semiconductor, Inc

22.4
The QSPI uses a dedicated 80-byte block of static RAM accessible to the module and CPU to perform
queued operations. The RAM is divided into three segments:
Freescale Semiconductor
QSPI_CS
Address: QAR[ADDR]
BITSE
CONT
DSCK
Field
11–8
7–0
DT
15
14
13
12
•
•
Reset
16 command control bytes (command RAM)
32 transmit data bytes (transmit data RAM)
W CONT BITSE
R
Functional Description
Continuous.
0 Chip selects return to inactive level defined by QWR[CSIV] when a single word transfer is complete.
1 Chip selects return to inactive level defined by QWR[CSIV] only after the transfer of the queue entries (max of 16
Note: To keep the chip selects asserted for transfers beyond 16 words, the QWR[CSIV] bit must be set to control
Bits per transfer enable.
0 Eight bits
1 Number of bits set in QMR[BITS]
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
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.
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. Bits 11-8 map directly to the
corresponding QSPI_CSn pins. If more than four chip selects are needed, then an external demultiplexor can be
used with the QSPI_CSn pins.
0 Enable chip select.
1 Mask chip select.
Note: Not all chip selects may be available on all device packages. See
Reserved, must be cleared.
15
—
words).
a latency requirement. The delay between transfers is determined by QDLYR[DTL].
The command RAM is accessed only using the most significant byte of
QDR and indirect addressing based on QAR[ADDR].
the level that the chip selects return to after the first transfer.
on which chip selects are pinned-out.
—
14
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3
DT
—
13
Figure 22-9. Command RAM Registers (QCR0–QCR15)
DSCK
Table 22-9. QCR0–QCR15 Field Descriptions
—
12
—
11
10
—
QSPI_CS
NOTE
—
Description
9
—
8
—
0
7
Chapter 14, “Signal Descriptions,”
—
0
6
Queued Serial Peripheral Interface (QSPI)
—
0
5
—
0
4
Access: CPU write-only
—
0
3
—
2
0
—
0
1
for details
—
0
0
22-9