Datasheet

 2009-2012 Microchip Technology Inc. DS70593D-page 181
dsPIC33FJXXXGPX06A/X08A/X10A
16.0 SERIAL PERIPHERAL
INTERFACE (SPI)
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, Analog-to-Digital Converters
(ADC), etc. The SPI module is compatible with SPI and
SIOP from Motorola
®
.
Each SPI module consists of a 16-bit shift register,
SPIxSR (where x = 1 or 2), used for shifting data in and
out, and a buffer register, SPIxBUF. A control register,
SPIxCON, configures the module. Additionally, a status
register, SPIxSTAT, indicates various status conditions.
The serial interface consists of 4 pins: SDIx (serial data
input), SDOx (serial data output), SCKx (shift clock input
or output), and SSx
(active-low slave select).
In Master mode operation, SCK is a clock output but in
Slave mode, it is a clock input.
FIGURE 16-1: SPI MODULE BLOCK DIAGRAM
Note 1: This data sheet summarizes the features
of the dsPIC33FJXXXGPX06A/X08A/
X10A family of devices. However, it is not
intended to be a comprehensive refer-
ence source. To complement the infor-
mation in this data sheet, refer to Section
18. “Serial Peripheral Interface (SPI)”
(DS70206) in the “dsPIC33F/PIC24H
Family Reference Manual”, which is
available from the Microchip web site
(www.microchip.com).
2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
Section 4.0 “Memory Organization” in
this data sheet for device-specific register
and bit information.
Note: In this section, the SPI modules are
referred to together as SPIx, or
separately as SPI1 and SPI2. Special
Function Registers will follow a similar
notation. For example, SPIxCON refers to
the control register for the SPI1 or SPI2
module.
Internal Data Bus
SDIx
SDOx
SSx
SCKx
SPIxSR
bit 0
Shift Control
Edge
Select
F
CY
Primary
1:1/4/16/64
Enable
Prescaler
Sync
SPIxBUF
Control
Transfer
Transfer
Write SPIxBUF
Read SPIxBUF
16
SPIxCON1<1:0>
SPIxCON1<4:2>
Master Clock
Clock
Control
Secondary
Prescaler
1:1 to 1:8
SPIxRXB SPIxTXB