Motorola DSP56309 User Manual page 67

Signal/Connection Descriptions
Host Interface (HI08)
Signal
Name
HRW
HRD/HRD
PB11 Input or
Output
HDS/HDS
HWR/
HWR
Input or
PB12 Output
2-20
Table 2-11 Host Interface (Continued)
State
Type During
Reset
Input Input
Input
Input Input
Input
DSP56309UM/D
Signal Description
Host Read/WriteÑWhen HI08 is
programmed to interface a single-data-strobe
host bus and the HI function is selected, this
signal is the host read/write (HRW) input.
Host Read DataÑWhen HI08 is
programmed to interface a
double-data-strobe host bus and the HI
function is selected, this signal is the host
read data strobe (HRD) Schmitt-trigger
input. The polarity of the data strobe is
programmable, but is configured as
active-low (HRD) after reset.
Port B 11ÑWhen the HI08 is configured as
GPIO through the HPCR, this signal is
individually programmed as an input or
output through the HDDR.
Host Data StrobeÑWhen HI08 is
programmed to interface a single-data-strobe
host bus and the HI function is selected, this
signal is the host data strobe (HDS)
Schmitt-trigger input. The polarity of the
data strobe is programmable, but is
configured as active-low (HDS) following
reset.
Host Write DataÑWhen HI08 is
programmed to interface a
double-data-strobe host bus and the HI
function is selected, this signal is the host
write data strobe (HWR) Schmitt-trigger
input. The polarity of the data strobe is
programmable, but is configured as
active-low (HWR) following reset.
Port B 12ÑWhen the HI08 is configured as
GPIO through the HPCR, this signal is
individually programmed as an input or
output through the HDDR.
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