3. Clock Frequency and Mode Selection Hardware Straps
72
Tsi308 User Manual
80D4000_MA001_02
Tundra Semiconductor Corporation
www.tundra.com
Figure 4: Primary clock inputs to Tsi308 PLLs
When operating in ‘non-RevC’ mode, P0_CLK is fed to an internal PLL that generates clock for
the PCI_A interface logic as well as core clock. The P0_CLK is also fed to two other internal
PLLs that generate HyperTransport transmit clocks for both the linksThe P1_CLK is fed to yet
another PLL that generates clock for the PCI_B interface logic.
If the Tsi308 is to perform synchronous link initialization with HyperTransport devices on either
side of it, the reference clock (P0_CLK) must be derived from the same base frequency source.
If not, asynchronous link initialization must be used. No phase relationship is required in either
mode.
When operating in ‘RevC mode’, Tsi308 derives core clock from REFCLK_C. RevC mode is
set through hardware strap option. A CORE PLL is used to generate core clock. REFCLK_C is
also fed to internal PLLs that generate HyperTransport transmit clocks for both the links.
P0_CLK and P1_CLK are fed to corresponding internal PLLs that generate clocks for the
PCI_A and PCI_B iterface logic respectively. If the Tsi308 is to perform synchronous link
initialization with HyperTransport devices on either side of it, the reference clock (REFCLK_C)
must be derived from the same base frequency source.
R E F C L K _ C
A D [ 1 5 ]
P 0 _ C L K
P 1 _ C L K
0
1
H T 0 _ P L L
H T 1 _ P L L
C O R E _ P L L
P C I _ A _ P L L
P C I _ B _ P L L
Содержание TSI308
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Страница 14: ...List of Figures 14 Tsi308 User Manual 80D4000_MA001_02 Tundra Semiconductor Corporation www tundra com ...
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Страница 187: ...4 Register Descriptions 187 Tsi308 User Manual 80D4000_MA001_02 Tundra Semiconductor Corporation www tundra com ...
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Страница 258: ...9 Ordering Information 258 Tsi308 User Manual 80D4000_MA001_02 Tundra Semiconductor Corporation www tundra com ...
Страница 260: ...Index 260 Tsi308 User Manual 80D4000_MA001_02 Tundra Semiconductor Corporation www tundra com ...