dsp56004 Freescale Semiconductor, Inc, dsp56004 Datasheet - Page 13

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

INTERRUPT AND MODE CONTROL
MOTOROLA
MODA
IRQA
Signal Name
The interrupt and mode control signals select the DSP’s operating mode as it comes
out of hardware reset and receives interrupt requests from external sources after
reset.
Signal
Input
Type
Freescale Semiconductor, Inc.
For More Information On This Product,
Table 1-7 Interrupt and Mode Control Signals
Input (MODA) Mode Select A—This input signal has three functions:
State during
Reset
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DSP56004/D, Rev. 3
MODA is read and internally latched in the DSP when the
processor exits the Reset state. The logic state present on the
MODA, MODB, and MODC pins selects the initial DSP
operating mode. Several clock cycles after leaving the Reset
state, the MODA signal changes to the external interrupt
request IRQA. The DSP operating mode can be changed by
software after reset.
External Interrupt Request A (IRQA)—The IRQA input is a
synchronized external interrupt request. It may be
programmed to be level-sensitive or negative-edge-
triggered. When the signal is edge-triggered, triggering
occurs at a voltage level and is not directly related to the fall
time of the interrupt signal. However, as the fall time of the
interrupt signal increases, the probability that noise on IRQA
will generate multiple interrupts also increases.
While the DSP is in the Stop mode, asserting IRQA gates on
the oscillator and, after a clock stabilization delay, enables
clocks to the processor and peripherals. Hardware reset
causes this input to function as MODA.
•
•
•
to work with the MODB and MODC signals to select
the DSP’s initial operating mode,
to allow an external device to request a DSP
interrupt after internal synchronization, and
to turn on the internal clock generator when the DSP
is in the Stop processing state, causing the DSP to
resume processing.
Signal Description
Signal/Connection Descriptions
Interrupt and Mode Control
1-7