Microchip Technology GPIODM-KPLCD Data Sheet

© 2009 Microchip Technology Inc.

 

DS39632E-page 197

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,
display drivers, A/D converters, etc. The MSSP module
can operate in one of two modes:
• Serial Peripheral Interface (SPI)
• Inter-Integrated Circuit (I

2

C™)

- Full Master mode
- Slave mode (with general address call)

The I

2

C interface supports the following modes in

hardware:
• Master  mode
• Multi-Master mode
• Slave mode

The MSSP module has three associated control regis-
ters. These include a status register (SSPSTAT) and
two control registers (SSPCON1 and SSPCON2). The
use of these registers and their individual Configuration
bits differ significantly depending on whether the MSSP
module is operated in SPI or I

2

C mode.

Additional details are provided under the individual
sections.

The SPI mode allows 8 bits of data to be synchronously
transmitted and received simultaneously. All four
modes of the SPI are supported. To accomplish
communication, typically three pins are used:
• Serial Data Out (SDO) – RC7/RX/DT/SDO
• Serial Data In (SDI) – RB0/AN12/INT0/FLT0/SDI/SDA
• Serial Clock (SCK) – RB1/AN10/INT1/SCK/SCL
Additionally, a fourth pin may be used when in a Slave
mode of operation:
• Slave Select (SS) – RA5/AN4/SS/HLVDIN/C2OUT
Figure 19-1 shows the block diagram of the MSSP
module when operating in SPI mode. 

(          )

Read

Write

Internal

Data Bus

SSPSR reg

SSPM3:SSPM0

bit0

Shift

Clock

SS Control

Enable

Edge

Select

Clock Select

TMR2 Output

T

OSC

Prescaler

4, 16, 64

2

Edge

Select

2

4

Data to TX/RX in SSPSR

TRIS bit

2

SMP:CKE

SDO

SSPBUF reg

SDI

SS

SCK

Only those pin functions relevant to SPI
operation are shown here.