
2010 Microchip Technology Inc.
Preliminary
DS41350E-page 139
PIC18F/LF1XK50
15.0
MASTER SYNCHRONOUS
SERIAL PORT (MSSP)
MODULE
15.1
Master SSP (MSSP) Module
Overview
The Master Synchronous Serial Port (MSSP) module is
a serial interface, useful for communicating with other
peripheral or microcontroller devices. These peripheral
devices may be serial EEPROMs, shift registers, dis-
play drivers, A/D converters, etc. The MSSP module
can operate in one of two modes:
Serial Peripheral Interface (SPI)
Inter-Integrated Circuit (I2C)
- Full Master mode
- Slave mode (with general address call)
The I2C interface supports the following modes in
hardware:
Master mode
Multi-Master mode
Slave mode
15.2
SPI Mode
The SPI mode allows 8 bits of data to be synchronously
transmitted and received simultaneously. All four
modes
of
SPI
are
supported.
To
accomplish
communication, typically three pins are used:
Serial Data Out – SDO
Serial Data In – SDI
Serial Clock – SCK
Additionally, a fourth pin may be used when in a Slave
mode of operation:
Slave Select – SS
module when operating in SPI mode.
FIGURE 15-1:
MSSP BLOCK DIAGRAM
(SPI MODE)
(
)
Read
Write
Internal
Data Bus
SSPSR Reg
SSPM<3:0>
bit 0
Shift
Clock
SS Control
Enable
Edge
Select
Clock Select
TMR2 Output
TOSC
Prescaler
4, 16, 64
2
Edge
Select
2
4
TRIS bit
SDO
SSPBUF Reg
SDI/SDA
SS
SCK/SCL