Partner Connection Interfaces - Altera cyclone V Technical Reference

19-16

Partner Connection Interfaces

Figure 19-7: SPI Configured as Master Device
Partner Connection Interfaces
The SPI can connect to any serial-master or serial-slave peripheral device using one of several interfaces.
Motorola SPI Protocol
With SPI, the clock polarity (SCPOL) configuration parameter determines whether the inactive state of
the serial clock is high or low. The data frame can be 4 to 16 bits in length. †
When the configuration parameter (SCPH = 0), data transmission begins on the falling edge of the slave
select signal. The first data bit is captured by the master and slave peripherals on the first edge of the serial
clock; therefore, valid data must be present on the
The slave select signal takes effect only when used as slave SPI. For master SPI, the data transmission
begins as soon as the output enable signal is deasserted.
The following signals are illustrated in the timing diagrams in this section: †
Altera Corporation
SPI Master 1
txd
ssi_oe_n
rxd
sclk_out
ss_n[0]
ss_n[1]
ss_in_n
Glue
Logic
and lines prior to the first serial clock edge. †
txd rxd
Slave Peripheral 1
DI
DO
SCLK
SS
.
.
.
Slave Peripheral n
DI
DO
SCLK
SS
SPI Controller
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2016.10.28