Motorola ColdFire MCF5281 User Manual

Page 408

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Queued Serial Peripheral Interface (QSPI)

22-4

Freescale Semiconductor

Table 22-3. QMR Field Descriptions

Field

Description

15

MSTR

Master mode enable.
0 Reserved, do not use.
1 The QSPI is in master mode. Must be set for the QSPI module to operate correctly.

14

Reserved, must be cleared.

13–10

BITS

Transfer size. Determines the number of bits to be transferred for each entry in the queue.

9

CPOL

Clock polarity. Defines the clock polarity of QSPI_CLK.
0 The inactive state value of QSPI_CLK is logic level 0.
1 The inactive state value of QSPI_CLK is logic level 1.

8

CPHA

Clock phase. Defines the QSPI_CLK clock-phase.
0 Data captured on the leading edge of QSPI_CLK and changed on the following edge of QSPI_CLK.
1 Data changed on the leading edge of QSPI_CLK and captured on the following edge of QSPI_CLK.

7–0

BAUD

Baud rate divider. The baud rate is selected by writing a value in the range 2–255. A value of zero disables the QSPI.
A value of 1 is an invalid setting. The desired QSPI_CLK baud rate is related to the internal bus clock and
QMR[BAUD] by the following expression:

QMR[BAUD] = f

sys/

/ (2 ×

[desired QSPI_CLK baud rate])

BITS

Bits per Transfer

0000

16

0001–0111

Reserved

1000

8

1001

9

1010

10

1011

11

1100

12

1101

13

1110

14

1111

15

MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3

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