dsp56004 Freescale Semiconductor, Inc, dsp56004 Datasheet - Page 22

• Manufacturer Part Number: dsp56004
• Description: Symphonytm Audio Dsp Family 24-bit Digital Signal Processors
• Manufacturer: Freescale Semiconductor, Inc

Signal/Connection Descriptions
General Purpose I/O
GENERAL PURPOSE I/O
ON-CHIP EMULATION (OnCE
1-16
GPIO0–
GPIO3
DSI
OS0
Signal
Name
Signal
Name
There are four signals associated with the OnCE port controller and its serial
interface.
Output
Signal
Input
Type
Open-drain
Output, or
Standard
Output,
Signal
Type
Input
Table 1-11 General Purpose I/O (GPIO) Signals
Table 1-12 On-Chip Emulation Port Signals
State during
Driven Low
Output,
Freescale Semiconductor, Inc.
Reset
For More Information On This Product,
Disconnected
State during
Reset
DSP56004/D, Rev. 3
Go to: www.freescale.com
TM
Debug Serial Input (DSI)—The DSI signal is the signal
through which serial data or commands are provided to the
OnCE port controller. The data received on the DSI signal
will be recognized only when the DSP has entered the
Debug mode of operation. Data must have valid TTL logic
levels before the serial clock falling edge. Data is always
shifted into the OnCE port Most Significant Bit (MSB) first.
Operating Status 0 (OS0)—When the DSP is not in the Debug
mode, the OS0 signal provides information about the DSP
status if it is an output and used in conjunction with the OS1
signal. When switching from output to input, the signal is
tri-stated.
Note:
) PORT
If the OnCE port is in use, an external pull-down resistor
should be attached to the DSI/OS0 signal. If the OnCE
port is not in use, the resistor is not required.
GPIO lines can be used for control and handshake
functions between the DSP and external circuitry.
Each GPIO line can be configured individually as
disconnected, open-drain output, standard output,
or an input.
Note:
Hardware reset or software reset configures all
the GPIO lines as disconnected (external
circuitry connected to these pins may need pull-
ups until the pins are configured for operation).
Signal Description
Signal Description
MOTOROLA