PIC24FJ64GA006-I Datasheet, PDF (127/258 Pages) Microchip Technology – 64/80/100-Pin, General Purpose, 16-Bit Flash Microcontrollers

PIC24FJ128GA010 FAMILY
15.0 SERIAL PERIPHERAL
INTERFACE (SPI)
Note:
This data sheet summarizes the features
of this group of PIC24F devices. It is not
intended to be a comprehensive refer-
ence source. Refer to Section 23. “Serial
Peripheral Interface (SPI)” (DS39699) in
the “PIC24F Family Reference Manual”
for more information.
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 reg-
isters, display drivers, A/D Converters, etc. The SPI
module is compatible with SPI and SIOP interfaces
from Motorola^®.
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.
Note:
Do not perform read-modify-write opera-
tions (such as bit-oriented instructions) on
the SPIxBUF register, in either Standard
or Enhanced Buffer mode.
The module also supports a basic framed SPI protocol
while operating in either Master or Slave modes. 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.
A block diagram of the module is shown in Figure 15-1
and Figure 15-2.
Note:
In this section, the SPI modules are
referred to together as SPIx, or separately
as SPI1 and SPI2. Special Function Reg-
isters will follow a similar notation. For
example, SPIxCON refers to the control
register for the SPI1 or SPI2 module.
To set up the SPI module for the Standard Master mode
of operation:
1. If using interrupts:
a) Clear the SPIxIF bit in the respective IFSx
register.
b) Set the SPIxIE bit in the respective IECx
register.
c) Write the SPIxIP bits in the respective IPCx
register to set the interrupt priority.
2. Write the desired settings to the SPIxCON
register with MSTEN (SPIxCON1<5>) = 1.
3. Clear the SPIROV bit (SPIxSTAT<6>).
4. Enable SPI operation by setting the SPIEN bit
(SPIxSTAT<15>).
5. Write the data to be transmitted to the SPIxBUF
register. Transmission (and reception) will start
as soon as data is written to the SPIxBUF
register.
To set up the SPI module for the Standard Slave mode
of operation:
1. Clear the SPIxBUF register.
2. If using interrupts:
a) Clear the SPIxIF bit in the respective IFSx
register.
b) Set the SPIxIE bit in the respective IECx
register.
c) Write the SPIxIP bits in the respective IPCx
register to set the interrupt priority.
3. Write the desired settings to the SPIxCON1 and
SPIxCON2 registers with MSTEN
(SPIxCON1<5>) = 0.
4. Clear the SMP bit.
5. If the CKE bit is set, then the SSEN bit
(SPIxCON1<7>) must be set to enable the
SSx pin.
6. Clear the SPIROV bit (SPIxSTAT<6>).
7. Enable SPI operation by setting the SPIEN bit
(SPIxSTAT<15>).
 2005-2012 Microchip Technology Inc.
DS39747F-page 127