Motorola DSP56009 User Manual page 54

Signal Descriptions
Serial Host Interface (SHI)
Table 2-8 Serial Host Interface (SHI) signals (Continued)
Signal
Signal Name
Type
MOSI Input or
Output
HA0 Input
SS Input
HA2 Input
2-16
State
during
Reset
Tri-stated SPI Master-Out-Slave-In (MISO)—When the SPI
is configured as a master, MOSI is the master data
output line. The MOSI signal is used in
conjunction with the MISO signal for transmitting
and receiving serial data. MOSI is the slave data
input line when the SPI is configured as a slave.
This signal is a Schmitt-trigger input when
configured for the SPI Slave mode.
2
I C Slave Address 0 (HA0)—This signal uses a
Schmitt-trigger input when configured for the I
mode. When configured for I
HA0 signal is used to form the slave device
address. HA0 is ignored when the SHI is
configured for the I
Note: This signal is tri-stated during hardware reset,
software reset, or individual reset (no need for
external pull-up in this state).
Tri-stated SPI Slave Select (SS)—This signal is an active low
Schmitt-trigger input when configured for the SPI
mode. When configured for the SPI Slave mode,
this signal is used to enable the SPI slave for
transfer. When configured for the SPI Master
mode, this signal should be kept deasserted. If it is
asserted while configured as SPI master, a bus
error condition will be flagged.
2
I C Slave Address 2 (HA2)—This signal uses a
Schmitt-trigger input when configured for the I
mode. When configured for the I
the HA2 signal is used to form the slave device
address. HA2 is ignored in the I
SS is deasserted, the SHI ignores SCK clocks and
keeps the MISO output signal in the
high-impedance state.
Note: This signal is tri-stated during hardware reset,
software reset, or individual reset (no need for
external pull-up in this state).
DSP56009 User's Manual
Signal Description
2
C Slave mode, the
2
C Master mode.
2
C Slave mode,
2
C Master mode. If
MOTOROLA
2
C
2
C