mc68hc916y3 Freescale Semiconductor, Inc, mc68hc916y3 Datasheet - Page 268

• Manufacturer Part Number: mc68hc916y3
• Description: Mc68hc16y3 16 Bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

12.2.2 Pin Control and General-Purpose I/O
12.3 Serial Peripheral Interface (SPI)
12-4
MOTOROLA
The eight pins used by the SPI and SCI subsystems have alternate functions as
general-purpose I/O pins. Configuring the MCCI submodule includes programming
each pin for either general-purpose I/O or its serial interface function. In either function,
each pin must also be programmed as input or output.
The MCCI data direction register (MDDR) assigns each MCCI pin as either input or
output. The MCCI pin assignment register (MPAR) assigns the MOSI, MISO, and SS
pins as either SPI pins or general-purpose I/O. (The fourth pin, SCK, is automatically
assigned to the SPI whenever the SPI is enabled, for example, when the SPE bit in
the SPI control register is set.) The receiver enable (RE) and transmitter enable (TE)
bits in the SCI control registers (SCCR0A, SCCR0B) automatically assign the associ-
ated pin as an SCI pin when set or general-purpose I/O when cleared. Table 12-2
summarizes how pin function and direction are assigned.
The SPI submodule communicates with external peripherals and other MCUs via a
synchronous serial bus. The SPI is fully compatible with the serial peripheral interface
systems found on other Motorola devices such as the M68HC11 and M68HC05
families. The SPI can perform full duplex three-wire or half duplex two-wire transfers.
Serial transfer of 8 or 16 bits can begin with the MSB or LSB. The system can be con-
figured as a master or slave device.
TXDA/PMC7
RXDA/PMC6
TXDB/PMC5
RXDB/PMC4
MOSI/PMC1
MISO/PMC0
SCK/PMC2
SS/PMC3
Pin
MULTICHANNEL COMMUNICATION INTERFACE
Freescale Semiconductor, Inc.
For More Information On This Product,
Table 12-2 Pin Assignments
Function Assigned By
Go to: www.freescale.com
RE bit in SCCR0A
RE bit in SCCR0B
MOSI bit in MPAR
MISO bit in MPAR
TE bit in SCCR0A
TE bit in SCCR0B
SPE bit in SPCR
SS bit in MPAR
Direction Assigned By
MMDR7
MMDR6
MMDR5
MMDR4
MMDR3
MMDR2
MMDR1
MMDR0
MC68HC16Y3/916Y3
USER’S MANUAL