
Symphony DSP56724/DSP56725 Multi-Core Audio Processors, Rev. 0
2-6
Freescale Semiconductor
Signal Descriptions
2.2.3
SCAN
2.2.4
Clock and PLL
Table 2-5. SCAN Signals
Signal
Name
Type
State During
Reset
Description
SCAN
Input
Input
SCAN
Manufacturing test pin. This pin should be pulled low.
Uses internal pull-down resistor.
Table 2-6. Clock and PLL Signals
Signal
Name
Type
State During
Reset
Description
EXTAL
Input
Input
External Clock / Crystal Input
An external clock source must be connected to EXTAL to supply the clock to the
internal clock generator and PLL.
XTAL
Output
Chip Driven
Crystal Output
Connects the internal Crystal Oscillator output to an external crystal. If an external
clock is used, leave XTAL unconnected.
PLOCK
Output
MODC0
Input
PLL Lock/GPIO Port G Pin 0
During assertion of RESET, the PLOCK pin acts as a mode pin input, and when
RESET is de-asserted, the state of the PLOCK pin is latched into the Core-0 (MDC
of Core-0’s OMR). After RESET is de-asserted, PLOCK is output “0”; and goes high
when the internal PLL is locked.
MODC0
Input
MODC0
MODA0, MODB0, MODC0, and MODD0 levels select one of 16 initial chip operating
modes of DSP Core-0, and are latched into the DSP Core-0’s OMR when the
RESET signal is de-asserted.
PG0
Input, Output,
or
Disconnected
GPIO Port G0
When the PLOCK is configured as GPIO, this pin is individually programmable as
input, output, or internally disconnected.
Uses an internal pull-up resistor.
PINIT/NMI
Input
Input
PLL Initial/Nonmaskable Interrupt for DSP Core-0
During assertion of RESET, the value of PINIT/NMI is written into the PLL Enable
(PEN) bit of the PLL control register, determining whether the PLL is enabled or
disabled.
After RESET de-assertion and during normal instruction processing, the PINIT/NMI
Schmitt-trigger input is a negative-edge-triggered nonmaskable interrupt (NMI)
request for DSP Core-0, internally synchronized to the internal system clock.
Uses an internal pull-up resistor.