Spi Controller Overview - Altera cyclone V Technical Reference

cv_5v4
2016.10.28
The host processor accesses data, control, and status information about the SPI controller through the
system bus interface. The SPI also interfaces with the DMA Controller. †
The HPS includes two general-purpose SPI master controllers and two general-purpose SPI slave control‐
lers.
The SPI controller can connect to any other SPI device using any of the following protocols:
• Motorola SPI Protocol †
• Texas Instruments Serial Protocol (SSP) †
• National Semiconductor Microwire Protocol †

SPI Controller Overview

In order for the SPI controller to connect to a serial-master or serial-slave peripheral device, the peripheral
must have a least one of the following interfaces: †
• Motorola SPI protocol – A four-wire, full-duplex serial protocol from Motorola. The slave select line is
held high when the SPI controller is idle or disabled. For more information, refer to "Motorola SPI
Protocol". †
• Texas Instruments Serial Protocol (SSP) – A four-wire, full-duplex serial protocol. The slave select line
used for SPI and Microwire protocols doubles as the frame indicator for the SSP protocol. For more
information, refer to "Texas Instruments Synchronous Serial Protocol (SSP)". †
• National Semiconductor Microwire – A half-duplex serial protocol, which uses a control word
transmitted from the serial master to the target serial slave. For more information, refer to "National
Semiconductor Microwire Protocol". You can program the FRF (frame format) bit field in the Control
Register 0 (
The serial protocols supported by the SPI controller allow for serial slaves to be selected or addressed using
hardware. Serial slaves are selected under the control of dedicated hardware select lines. The number of
select lines generated from the serial master is equal to the number of serial slaves present on the bus. The
serial-master device asserts the select line of the target serial slave before data transfer begins. This
architecture is illustrated in part A of
When implemented in software, the input select line for all serial slave devices should originate from a
single slave select output on the serial master. In this mode it is assumed that the serial master has only a
single slave select output. If there are multiple serial masters in the system, the slave select output from all
masters can be logically ANDed to generate a single slave select input for all serial slave devices. †
The main program in the software domain controls selection of the target slave device; this architecture is
illustrated in part B of the
the serial transfer request from the master device. †
SPI Controller
Send Feedback
) to select which protocol is used. †
CTRLR0
Figure
Figure 19-2
figure below. Software would control which slave is to respond to
19-2. †
SPI Controller Overview
Altera Corporation
19-5