Microchip Technology MA240029 データシート

 2010-2011 Microchip Technology Inc.

DS39996F-page 221

The Serial Peripheral Interface (SPI) module is a
synchronous 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 SPI
module is compatible with the SPI and SIOP Motorola

®

interfaces. All devices of the PIC24FJ128GA310 family
include two SPI modules.
The module supports operation in two buffer modes. In
Standard mode, data is shifted through a single serial
buffer. In Enhanced Buffer mode, data is shifted
through an 8-level FIFO buffer.

The module also supports a basic framed SPI protocol
while operating in either Master or Slave mode. A total
of four framed SPI configurations are supported.
The SPI serial interface consists of four pins:
• SDIx: Serial Data Input
• SDOx: Serial Data Output
• SCKx: Shift Clock Input or Output
• SSx: Active-Low Slave Select or Frame 

Synchronization I/O Pulse

The SPI module can be configured to operate using 2,
3 or 4 pins. In the 3-pin mode, SSx is not used. In the
2-pin mode, both SDOx and SSx are not used. 
Block diagrams of the module in Standard and
Enhanced modes are shown in 

 and

This data sheet summarizes the features of
this group of PIC24F devices. It is not
intended to be a comprehensive reference
source. For more information, refer to the
“PIC24F Family Reference Manual”

,

 (DS39699). The information in this

data sheet supersedes the information in
the FRM.

Do not perform read-modify-write opera-
tions (such as bit-oriented instructions) on
the SPIxBUF register in either Standard or
Enhanced Buffer mode.

In this section, the SPI modules are
referred to together as SPIx or separately
as SPI1, SPI2 or SPI3. Special Function
Registers will follow a similar notation. For
example, SPIxCON1 and SPIxCON2
refer to the control registers for any of the
3 SPI modules.