Datasheet

Serial Peripheral Interface Module (SPI)
Technical Data MC68HC908LJ12 — Rev. 2.1
270 Serial Peripheral Interface Module (SPI) Freescale Semiconductor
14.13.3 SPSCK (Serial Clock). . . . . . . . . . . . . . . . . . . . . . . . . . . . .292
14.13.4 SS (Slave Select) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .292
14.13.5 CGND (Clock Ground) . . . . . . . . . . . . . . . . . . . . . . . . . . . .293
14.14 I/O Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .294
14.14.1 SPI Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .294
14.14.2 SPI Status and Control Register . . . . . . . . . . . . . . . . . . . .296
14.14.3 SPI Data Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .299
14.2 Introduction
This section describes the serial peripheral interface (SPI) module,
which allows full-duplex, synchronous, serial communications with
peripheral devices.
14.3 Features
Features of the SPI module include the following:
• Full-duplex operation
• Master and slave modes
• Double-buffered operation with separate transmit and receive
registers
• Four master mode frequencies (maximum = bus frequency ÷ 2)
• Maximum slave mode frequency = bus frequency
• Serial clock with programmable polarity and phase
• Two separately enabled interrupts:
– SPRF (SPI receiver full)
– SPTE (SPI transmitter empty)
• Mode fault error flag with CPU interrupt capability
• Overflow error flag with CPU interrupt capability
• Programmable wired-OR mode
•I
2
C (inter-integrated circuit) compatibility
• I/O (input/output) port bit(s) software configurable with pullup
device(s) if configured as input port bit(s)