PIC18F2331/2431/4331/4431
19.2 SPI Mode
19.0 SYNCHRONOUS SERIAL PORT
(SSP) MODULE
This section contains register definitions and opera-
tional characteristics of the SPI module. Additional
information on the SPI module can be found in the
”PIC® Mid-Range MCU Family Reference Manual”
(DS33023).
19.1 SSP Module Overview
The Synchronous Serial Port (SSP) module is a serial
interface useful for communicating with other periph-
eral or microcontroller devices. These peripheral
devices may be serial EEPROMs, shift registers,
display drivers, A/D Converters, etc. The SSP module
can operate in one of two modes:
SPI mode allows 8 bits of data to be synchronously
transmitted and received simultaneously. To accomplish
communication, typically three pins are used:
• Serial Data Out (SDO)
• Serial Data In (SDI)
• Serial Clock (SCK)
• Serial Peripheral Interface (SPI)
• Inter-Integrated Circuit (I2C™)
An overview of I2C operations and additional
information on the SSP module can be found in the
“PIC® Mid-Range MCU Family Reference Manual”
(DS33023).
Additionally, a fourth pin may be used when in a Slave
mode of operation:
• Slave Select (SS)
When initializing the SPI, several options need to be
specified. This is done by programming the appropriate
control bits in the SSPCON (SSPCON<5:0>) and
SSPSTAT<7:6> registers. These control bits allow the
following to be specified:
Refer to application note AN578, “Use of the SSP
Module in the I 2C™ Multi-Master Environment”
(DS00578).
• Master mode (SCK is the clock output)
• Slave mode (SCK is the clock input)
• Clock polarity (Idle state of SCK)
• Clock edge (output data on rising/falling edge of
SCK)
• Clock rate (Master mode only)
• Slave Select mode (Slave mode only)
2010 Microchip Technology Inc.
DS39616D-page 205
MICROCHIP [ MICROCHIP ]
