37.2.1 SPSCK — SPI Serial ClockWhen the SPI is enabled as a slave, this pin is the serial clock input. When the SPI isenabled as a master, this pin is the serial clock output.37.2.2 MOSI — Master Data Out, Slave Data InWhen the SPI is enabled as a master and SPI pin control zero (SPC0) is 0 (notbidirectional mode), this pin is the serial data output. When the SPI is enabled as a slaveand SPC0 is 0, this pin is the serial data input. If SPC0 is 1 to select single-wirebidirectional mode, and master mode is selected, this pin becomes the bidirectional dataI/O pin (MOMI). Also, the bidirectional mode output enable bit determines whether thepin acts as an input (BIDIROE is 0) or an output (BIDIROE is 1). If SPC0 is 1 and slavemode is selected, this pin is not used by the SPI and reverts to other functions (based onchip configuration).37.2.3 MISO — Master Data In, Slave Data OutWhen the SPI is enabled as a master and SPI pin control zero (SPC0) is 0 (notbidirectional mode), this pin is the serial data input. When the SPI is enabled as a slaveand SPC0 is 0, this pin is the serial data output. If SPC0 is 1 to select single-wirebidirectional mode, and slave mode is selected, this pin becomes the bidirectional data I/O pin (SISO), and the bidirectional mode output enable bit determines whether the pinacts as an input (BIDIROE is 0) or an output (BIDIROE is 1). If SPC0 is 1 and mastermode is selected, this pin is not used by the SPI and reverts to other functions (based onchip configuration).37.2.4 SS — Slave SelectWhen the SPI is enabled as a slave, this pin is the low-true slave select input. When theSPI is enabled as a master and mode fault enable is off (MODFEN is 0), this pin is notused by the SPI and reverts to other functions (based on chip configuration). When theSPI is enabled as a master and MODFEN is 1, the slave select output enable bitdetermines whether this pin acts as the mode fault input (SSOE is 0) or as the slave selectoutput (SSOE is 1).External Signal DescriptionKL25 Sub-Family Reference Manual, Rev. 3, September 2012660 Freescale Semiconductor, Inc.
