Symphony DSP56724/DSP56725 Multi-Core Audio Processors, Rev. 0
7-4
Freescale Semiconductor
Clock Generation Module (CGM)
7.1.4
External Signal Description
lists the signal properties.
7.2
Functional Description
7.2.1
Clocks
The CGM has two clock sources, EXTAL and TCLK. The PLL is used in processing the EXTAL clock.
The CGM outputs various clocks.
7.2.2
Reset
The CGM can only be reset by external asynchronous reset.
7.2.3
Interrupts
The CGM does not generate any interrupts.
7.2.4
Internal PLL Block
This section describes the PLL control components and its operation.
Table 7-2. Signal Properties
Signal
Name
Function
I/O
Reset
Pull-Up
PINIT
During assertion of a hardware reset, the value of the PINIT input pin is written into
the PCTL PLL Enable (PEN) bit.
After a hardware reset is de-asserted, the PLL ignores the PINIT pin.
The default PCTL setting when PINIT is asserted is $2B60C2.
Input
Input
Pull-Up
EXTAL
An external clock is required to drive the DSP. The external clock is input via the
EXTAL pin, passing the clock through the PLL and clock generator for optional
frequency multiplication.
Input
Input
–
XTAL
An external crystal between the values of 10 MHz and 25 MHz can be driven from
the XTAL pin. The external crystal should be connected to both the XTAL and
EXTAL pins to provide the source clock frequency.
Output Chip-Driven
–
PLL lock
On-chip system PLL lock indicator
Output
0
–