9- 20
MC68341 USER’S MANUAL
MOTOROLA
or
SPBR = System Clock/(2
SCK Baud Rate Desired)
(9-2)
where SPBR equals 2, 3, 4, . . . , 255.
Programming SPBR with the values zero or one disables the QSPI baud rate generator.
SCK is disabled and assumes its inactive state value. No serial transfers occur. SPBR
has 254 active values. Table 9-9 lists several possible baud values and the
corresponding SCK frequency based on a 16.78-MHz system clock.
Table 9-9. Examples of SCK Frequencies
System
Clock
Frequency
Required
Division
Ratio
Value
of
SPBR
Actual
SCK Frequency
16.78 MHz
4
8
16
34
168
510
2
4
8
17
84
255
4.19 MHz
2.10 MHz
1.05 MHz
493 kHz
100 kHz
33 kHz
9.5.4.2 QSPI CONTROL REGISTER 1 (SPCR1). SPCR1 contains parameters for
configuring the QSPI before it is enabled. Although the CPU can read and write this
register, the QSPM has read access only, except for SPE. This bit is automatically cleared
by the QSPI after completing all serial transfers or when a mode fault occurs.
SPCR1
$81A
15
14
13
12
11
10
9876543210
SPE
DSCKL
DTL
RESE
T:
0000010000000100
SPE—QSPI Enable
1 = The QSPI is enabled and the pins allocated by QSPM register QPAR are
controlled by the QSPI.
0 = The QSPI is disabled, and the seven QSPI pins can be used as general-purpose
I/O pins, regardless of the values in QPAR.
This bit enables or disables the QSPI Submodule. Setting SPE causes the QSPI to
begin operation. If the QSPI is a master, setting SPE causes the QSPI to begin initiating
serial transfers. If the QSPI is a slave, the QSPI begins monitoring the PCS0/SS pin to
respond to the external initiation of a serial transfer.
When the QSPI is disabled, the CPU may use the QSPI RAM. When the QSPI is
enabled, both the QSPI and the CPU have access to the QSPI RAM. The CPU has both
read and write access capability to all 80 bytes of the QSPI RAM. The QSPI can read
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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