MPC8264AVR datasheet(19/48 Pages) MOTOROLA

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MOTOROLA

MPC826xA (HiP4) Family Hardware Speciﬁcations

Electrical and Thermal Characteristics

Figure 11 shows signal behavior in MEMC mode.

Figure 11. MEMC Mode Diagram

NOTE

Generally, all MPC826xA bus and system output signals are driven from

the rising edge of the input clock (CLKin). Memory controller signals,

however, trigger on four points within a CLKin cycle. Each cycle is

divided by four internal ticks: T1, T2, T3, and T4. T1 always occurs at the

rising edge, and T3 at the falling edge, of CLKin. However, the spacing of

T2 and T4 depends on the PLL clock ratio selected, as shown in Table 11.

Figure 12 is a graphical representation of Table 11.

Figure 12. Internal Tick Spacing for Memory Controller Signals

Table 11. Tick Spacing for Memory Controller Signals

PLL Clock Ratio

Tick Spacing (T1 Occurs at the Rising Edge of CLKin)

1:2, 1:3, 1:4, 1:5, 1:6

1/4 CLKin

1/2 CLKin

3/4 CLKin

1:2.5

3/10 CLKin

1/2 CLKin

8/10 CLKin

1:3.5

4/14 CLKin

1/2 CLKin

11/14 CLKin

CLKin

V_CLK

Memory controller signals

sp34/sp30

CLKin

for 1:2.5

for 1:3.5

CLKin

for 1:2, 1:3, 1:4, 1:5, 1:6

MPC8264AVR Datenblatt(PDF) 19 Page - Motorola, Inc