DSP56303 FREESCALE [Freescale Semiconductor, Inc], DSP56303 Datasheet - Page 117

• Manufacturer Part Number: DSP56303
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Freescale Semiconductor
Bit Number
13
12
11
10
9
8
7
6
Table 6-12. Host Port Control Register (HPCR) Bit Definitions (Continued)
Bit Name
HMUX
HROD
HCSP
HDDS
HDSP
HASP
HEN
Reset Value
0
0
0
0
0
0
0
0
DSP56303 User’s Manual, Rev. 2
Host Chip Select Polarity
If the HCSP bit is cleared, the host chip select (HCS) signal is configured as
an active low input and the HI08 is selected when the HCS signal is low. If
the HCSP signal is set, HCS is configured as an active high input and the
HI08 is selected when the HCS signal is high.
Host Dual Data Strobe
If the HDDS bit is cleared, the HI08 operates in single-strobe bus mode. In
this mode, the bus has a single data strobe signal for both reads and writes.
If the HDDS bit is set, the HI08 operates in dual strobe bus mode. In this
mode, the bus has two separate data strobes: one for data reads, the other
for data writes. See Figure 6-13 on page -19 and Figure 6-14 on page -19
for details on dual and single strobe modes.
Host Multiplexed Bus
If HMUX is set, the HI08 operates in multiplex mode, latching the lower
portion of a multiplexed address/data bus. In this mode the internal address
line values of the host registers are taken from the internal latch. If HMUX is
cleared, it indicates that the HI08 is connected to a non-multiplexed type of
bus. The values of the address lines are then taken from the HI08-dedicated
address signals.
Host Address Strobe Polarity
If HASP is cleared, the host address strobe (HAS) signal is an active low
input, and the address on the host address/data bus is sampled when the
HAS signal is low. If HASP is set, HAS is an active-high address strobe
input, and the address on the host address or data bus is sampled when the
HAS signal is high.
Host Data Strobe Polarity
If HDSP is cleared, the data strobe signals are configured as active low
inputs, and data is transferred when the data strobe is low. If HDSP is set,
the data strobe signals are configured as active high inputs, and data is
transferred when the data strobe is high. The data strobe signals are either
HDS by itself or both HRD and HWR together.
Host Request Open Drain
Controls the output drive of the host request signals. In the single host
request mode (that is, when HDRQ is cleared in ICR), if HROD is cleared
and host requests are enabled (that is, if HREN is set and HEN is set in the
host port control register (HPCR)), then the HREQ signal is always driven by
the HI08. If HROD is set and host requests are enabled, the HREQ signal is
an open drain output. In the double host request mode (that is, when HDRQ
is set in the ICR), if HROD is cleared and host requests are enabled (that is,
if HREN is set and HEN is set in the HPCR), then the HTRQ and HRRQ
signals are always driven. If HROD is set and host requests are enabled, the
HTRQ and HRRQ signals are open drain outputs.
Reserved. Write to 0 for future compatibility.
Host Enable
If HEN is set, the HI08 operates as the host interface. If HEN is cleared, the
HI08 is not active, and all the HI08 signals are configured as GPIO signals
according to the value of the HDDR and HDR.
Description
DSP Core Programming Model
6-17