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P5040/P5020 Reference Design Board User Guide, Rev. 0
40
Freescale Semiconductor
Architecture
5.4.1
SYSCLK
A significant amount of P5040/P5020 timing is derived from SYSCLK input. The P5040/P5020 reference
design board has the following features:
•
SYSCLK pin is controlled by an IDT ICS307M-02 frequency synthesizer.
•
IDT device, as part of the reset/power-up sequence, is serially configured by 24 data bits via
ngPIXIS.
•
24 data bits can be controlled to set the SYSCLK speed to fine increments; this is done using the
dynamic (re)configuration facilities of remote access ngPIXIS.
•
To ease configuration, ngPIXIS pre-loads the 24-bit configuration pattern; this is done using one
of eight popular values and by sampling three switches located on the motherboard,
SW_SYSCLK[0...2].
Table 19. P5040/P5020 Clock Distribution
Clock
Frequency
Destination
Device
SYSCLK
33–200 MHz
SYSCLK
IDT ICS307M-02:
• t
R
typ = 1ns
t
F
typ = 1ns
• Duty-cycle <= 60%
• Jitter type = ± 120 ps
• 25MHz input clock oscillator
RTC
~50KHz
RTCCLK
FPGA
SD_REF_CLK1
100.00 MHz
125.00 MHz
156.25 MHz
SD2_REFCLK(p,n)
SLOT1 REFCLK(p,n)
• IDT 6T49278BNLGI8 generator
• RMS phase jitter type <= 3.04ps
• Ten selectable 100MHz, 125MHz,
156.25MHz and 312.5MHz clocks for
PCI Express, sRIO and GbE, HCSL
interface levels r
SD_REF_CLK2
100.00 MHz
125.00 MHz
156.25 MHz
SD2_REFCLK(p,n)
SLOT2 REFCLK(p,n)
AURORA DEBUG REFCLK(p,n)
SD_REF_CLK3
100.00 MHz
125.00 MHz
156.25 MHz
SD3_REFCLK(p,n)
TN8022 XAUI PHY
SD_REF_CLK4
100.00 MHz
125.00 MHz
156.25 MHz
P5040 SD4_REFCLK(p,n)
GTX_CLK125
125 MHz
P5040/P5020
• EC1_GTX_CLK125
• EC2_GTX_CLK125
• 1588_CLK_IN
(MUX with 1588 Riser Card REFCLK)
Vitess VSC8244 XTAL1
IDT ICS8304AMLN
• 1-to-4 Fanout Clock Buffer
• 125MHz input clock oscillator
• Maximum output skew = 45ps
USB_PHYCLK
24 MHz
USB_CLOCK_In
Clock oscillator
FPGA_CLK
33.33 MHz
FPGA
Clock Oscillator