MPC555
/
MPC556
QUEUED SERIAL MULTI-CHANNEL MODULE
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
14-10
DDRQS does not affect SCI pin function. TXDx pins are always outputs, and RXDx
pins are always inputs, regardless of whether they are functioning as SCI pins or as
PORTQS pins.
The port QS data register (PORTQS) latches I/O data. PORTQS writes drive pins de-
fined as outputs. PORTQS reads return data present on the pins. To avoid driving un-
defined data, write the first data to PORTQS before configuring DDRQS.
14.6.1 Port QS Data Register (PORTQS)
PORTQS determines the actual input or output value of a QSMCM port pin if the pin
is defined as general-purpose input or output. All QSMCM pins except the ECK pin can
be used as general-purpose input and/or output. When the SCIx transmitter is dis-
abled, TXDx is a discrete output; when the SCIx receiver is disabled, RXDx is a dis-
crete input. Writes to this register affect the pins defined as outputs; reads of this
register return the actual value of the pins.
Table 14-8 Effect of DDRQS on QSPI Pin Function
QSMCM Pin
Mode
DDRQS Bit
Bit State
Pin Function
MISO
Master
DDQS0
0
Serial data input to QSPI
1
Disables data input
Slave
0
Disables data output
1
Serial data output from QSPI
MOSI
Master
DDQS1
0
Disables data output
1
Serial data output from QSPI
Slave
0
Serial data input to QSPI
1
Disables data input
SCK
1
NOTES:
1. SCK/QGPIO6 is a digital I/O pin unless the SPI is enabled (SPE set in SPCR1), in which
case it becomes the QSPI serial clock SCK.
Master
DDQS2
—
Clock output from QSPI
Slave
—
Clock input to QSPI
PCS[0]/SS
Master
DDQS3
0
Assertion causes mode fault
1
Chip-select output
Slave
0
QSPI slave select input
1
Disables slave select input
PCS[1:3]
Master
DDQS[4:6]
0
Disables chip-select output
1
Chip-select output
Slave
0
Inactive
1
Inactive
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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