dsp56004 Freescale Semiconductor, Inc, dsp56004 Datasheet - Page 14

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

Signal/Connection Descriptions
Interrupt and Mode Control
1-8
MODB
IRQB
Signal Name
Signal
Input
Type
Table 1-7 Interrupt and Mode Control Signals (Continued)
Input (MODB) Mode Select B—This input signal has two functions:
State during
Freescale Semiconductor, Inc.
Reset
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MODB 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 MODB signal changes to the external interrupt
request IRQB. The DSP operating mode can be changed by
software after reset.
External Interrupt Request B (IRQB)—The IRQB 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 IRQB
will generate multiple interrupts also increases. Hardware
reset causes this input to function as MODB.
•
•
to work with the MODA and MODC signals to select
the DSP’s initial operating mode, and
to allow an external device to request a DSP
interrupt after internal synchronization.
Signal Description
MOTOROLA