DSP56303 datasheet(117/292 Pages) FREESCALE

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DSP Core Programming Model

DSP56303 User’s Manual, Rev. 2

Freescale Semiconductor

6-17

HCSP

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.

HDDS

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.

HMUX

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.

HASP

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.

HDSP

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.

HROD

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.

6HEN

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.

Table 6-12. Host Port Control Register (HPCR) Bit Definitions (Continued)

Bit Number

Bit Name

Reset Value

Description

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