MSC8122 Freescale Semiconductor, MSC8122 Datasheet - Page 22

• Manufacturer Part Number: MSC8122
• Description: Quad Digital Signal Processor
• Manufacturer: Freescale Semiconductor

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Electrical Characteristics
2.5.5
2.5.5.1
Generally, all MSC8122 bus and system output signals are driven from the rising edge of the reference clock (REFCLK). The
REFCLK is the
is divided by four internal ticks: T1, T2, T3, and T4. T1 always occurs at the rising edge of REFCLK (and T3 at the falling
edge), but the spacing of T2 and T4 depends on the PLL clock ratio selected, as Table 13 shows.
Figure 10 is a graphical representation of Table 13.
22
BCLK/SC140 clock
1:4, 1:6, 1:8, 1:10
System Bus Access Timing
1:3
1:5
CLKIN
Core Data Transfers
REFCLK
REFCLK
REFCLK
signal. Memory controller signals, however, trigger on four points within a REFCLK cycle. Each cycle
Figure 10. Internal Tick Spacing for Memory Controller Signals
T1
T1
T1
MSC8122 Quad Digital Signal Processor Data Sheet, Rev. 15
Table 13. Tick Spacing for Memory Controller Signals
T2
T2
T2
2/10 REFCLK
1/4 REFCLK
1/6 REFCLK
T2
T3
T3
T3
Tick Spacing (T1 Occurs at the Rising Edge of REFCLK)
T4
T4
T4
1/2 REFCLK
1/2 REFCLK
1/2 REFCLK
T3
for 1:4, 1:6, 1:8, 1:10
for 1:3
for 1:5
Freescale Semiconductor
7/10 REFCLK
3/4 REFCLK
4/6 REFCLK
T4