TMS320VC5407 datasheet(73/110 Pages) TI

73 / 110 page

Electrical Specifications

November 2001 − Revised April 2004

SPRS007D

X2/CLKIN

Crystal

Figure 5−2. Internal Divide-by-Two Clock Option With External Crystal

5.7

Clock Options

The frequency of the reference clock provided at the CLKIN pin can be divided by a factor of two or four or

multiplied by one of several values to generate the internal machine cycle.

5.7.1 Divide-By-Two and Divide-By-Four Clock Options

The frequency of the reference clock provided at the X2/CLKIN pin can be divided by a factor of two or four

to generate the internal machine cycle. The selection of the clock mode is described in Section 3.10.

When an external clock source is used, the frequency injected must conform to specifications listed in

Table 5−4.

An external frequency source can be used by applying an input clock to X2/CLKIN with X1 left unconnected.

Table 5−3 shows the configuration options for the CLKMD pins that generate the external divide-by-2 or

divide-by-4 clock option.

Table 5−3. Clock Mode Pin Settings for the Divide-By-2 and By Divide-by-4 Clock Options

CLKMD1

CLKMD2

CLKMD3

CLOCK MODE

CLKMD1

CLKMD2

CLKMD3

CLOCK MODE

1/2, PLL and oscillator disabled

1/4, PLL and oscillator disabled

1/2, PLL and oscillator disabled

TMS320VC5407 Datasheet(PDF) 73 Page - Texas Instruments