
Signals and Package Information
56F826 Technical Data, Rev. 14
Freescale Semiconductor
15
SRCK
(GPIOC2)
53
Input/Output
Input/Output
SSI Serial Receive Clock (SRCK)—
This bidirectional pin provides the serial bit 
rate clock for the Receive section of the SSI. The clock signal can be continuous 
or gated and 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.
STD
(GPIOC3)
54
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)
55
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)
56
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)
84
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)
85
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. 
Table 2-1 56F826 Signal and Package Information for the 100 Pin LQFP (Continued)
Signal 
Name
Pin No.
Type
Description