dsp56001a Freescale Semiconductor, Inc, dsp56001a Datasheet - Page 15

• Manufacturer Part Number: dsp56001a
• Description: 24-bit Digital Signal Processor
• Manufacturer: Freescale Semiconductor, Inc

MOTOROLA
HEN
PB12
HREQ
PB13
HACK
PB14
Signal
Name
Input or
Input or
Input or
Output
Output
Output
Output
Signal
Input
Open
Input
Type
drain
Freescale Semiconductor, Inc.
Tri-stated Host Enable—This input enables a data transfer on the host data bus.
Tri-stated Host Request—This signal is used by the Host Interface to request
Tri-stated Host Acknowledge—This input has two functions. It provides a host
during
For More Information On This Product,
Reset
State
Table 1-9 HI Signals (Continued)
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When HEN is asserted and HR/W is high, H0–H7 become outputs
and the host processor may read DSP56001A data. When HEN is
asserted and HR/W is low, H0–H7 become inputs. Host data is
latched in the DSP on the rising edge of HEN. Normally, a chip select
signal derived from host address decoding and an enable strobe are
used to generate HEN.
Port B GPIO 12 (PB12)—This signal is aGPIO signal called PB12
when the Host Interface is not being used.
After reset, the default state for this signal is GPIO input.
service from the host processor, DMA controller, or a simple external
controller.
Note:
Port B GPIO 13 (PB13)—This signal is a GPIO (not open-drain) signal
(PB13) when the Host Interface is not selected.
After reset, the default state for this signal is GPIO input.
acknowledge handshake signal for DMA transfers and it receives a
host interrupt acknowledge compatible with MC68000 family
processors.
Note:
Port B GPIO 14 (PB14)—This signal is a GPIO signal (PB14) when the
Host Interface is not selected, and may be programmed as a GPIO
signal when the Host Interface is selected.
After reset, the default state for this signal is GPIO input.
DSP56001A/D, Rev. 1
HREQ should always be pulled high when it is not in use.
HACK should always be pulled high when it is not in use.
Signal Description
Host Interface (HI) Port
DSP56001A
1-9