
56F827 Technical Data, Rev. 12
16
 Freescale Semiconductor
STD
(GPIOC3)
52
Output
Input/Output
SSI Transmit Data (STD)
—This output pin transmits serial data from the SSI 
Transmitter Shift Register.
Port C GPIO
—This is a General Purpose I/O (GPIO) pin with the capability of 
being individually programmed as input or output. 
After reset, the default state is GPIO input.
STFS
(GPIOC4)
51
Input
Input/Output
SSI Serial Transmit Frame Sync (STFS)—
This bidirectional pin is used by 
the Transmit section of the SSI as frame sync I/O or flag I/O. The STFS can be 
used by both the transmitter and receiver in synchronous mode. It is used to 
synchronize data transfer and can be an input or output pin.
Port C GPIO
—This is a General Purpose I/O (GPIO) pin with the capability of 
being individually programmed as input or output. 
After reset, the default state is GPIO input. 
STCK
(GPIOC5)
50
Input/ Output
Input/Output
SSI Serial Transmit Clock (STCK)
—This bidirectional pin provides the serial 
bit rate clock for the transmit section of the SSI. The clock signal can be 
continuous or gated. It can be used by both the transmitter and receiver in 
synchronous mode. 
Port C GPIO
—This is a General Purpose I/O (GPIO) pin with the capability of 
being individually programmed as input or output. 
After reset, the default state is GPIO input.
SCLK
(GPIOF4)
102
Input/Output
Input/Output
SPI Serial Clock
—In master mode, this pin serves as an output, clocking 
slaved listeners. In slave mode, this pin serves as the data clock input.
Port F GPIO
—This General Purpose I/O (GPIO) pin can be individually 
programmed as input or output. 
After reset, the default state is SCLK.
MOSI
(GPIOF5)
101
Input/Output
Input/Output
SPI Master Out/Slave In (MOSI)
—This serial data pin is an output from a 
master device and an input to a slave device. The master device places data 
on the MOSI line a half-cycle before the clock edge that the slave device uses 
to latch the data. 
Port F GPIO
—This General Purpose I/O (GPIO) pin can be individually 
programmed as input or output. 
MISO
(GPIOF6)
100
Input/Output
Input/Output
SPI Master In/Slave Out (MISO)
—This serial data pin is an input to a master 
device and an output from a slave device. The MISO line of a slave device is 
placed in the high-impedance state if the slave device is not selected. 
Port F GPIO
—This General Purpose I/O (GPIO) pin can be individually 
programmed as input or output. 
After reset, the default state is MISO.
Table 2-2 56F827 Signal and Package Information for the 128 Pin LQFP (Continued)
Signal Name
Pin No.
Type
Description